Terms Starting with "M"

1515 terms

M

M abbreviation for memory. See primary ability. M abbreviation for sample mean.

M-Cat

M-Cat n. see mephedrone.

M-cell

M-cell n. any of various large neurons in the two most ventral layers of the lateral geniculate nucleus. M-cells are the origin of the magnocellular system. The large retinal ganglion cells that provide input to the M-cells of the lateral geniculate nucleus are called M-ganglion cells. See also P-cell.

M–C SDS

M–C SDS abbreviation for Marlowe–Crowne Social Desirability Scale.

M’Naghten rule (McNaghten rule; McNaughten rule; McNaughton rule)

Sorry, "mnaghten-rule-mcnaghten-rule-mcnaughten-rule-mcnaughton-rule" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

MA

MA abbreviation for mental age.

MacArthur Scale of Subjective Social Status

MacArthur Scale of Subjective Social Status a measure of an individual’s perceived social standing, reflecting his or her impressions of current circumstances, background variables, and future opportunities. The scale consists of two 10-rung ladders on which respondents place an X to indicate their rank relative to others in their community and to others in the general population in terms of typical indicators of socioeconomic status, including income, education, and occupational status. The score for each ladder is the number of the rung chosen to represent one’s status, with a possible low score of 1 and a high score of 10. Research increasingly suggests that relative social position is an important predictor of overall functioning: High subjective social status has been linked to psychological factors that predispose individuals to better health trajectories and well-being. [developed in 2000 by U.S. psychologist Nancy E. Adler and colleagues]

mace

mace n. an aromatic spice made from the fibrous seed coat of nutmeg. Mace has been associated with the euphoric effects produced by nutmeg intoxication, although the active ingredients of nutmeg are concentrated primarily in the oil of the nut.

Mach bands

Mach bands an example of a contrast illusion produced by two or more adjacent rectangular gray stimuli or bands that differ in lightness. The part of the light band that borders the dark band appears to be lighter than the rest of the light band, whereas the part of the dark band along the border between the two bands appears to be darker than the rest of the dark band. [Ernst Mach]

Mach card

Mach card a card used to demonstrate the factors that influence the perception of the brightness of a surface. A gray card is folded in half like a book, placed on a surface so that the convex side faces the observer, and then illuminated from either the left or the right. Even though the side closest to the illumination is physically brighter than the other side of the card, both sides appear roughly equal in brightness, an example of brightness constancy. However, the concave–convex nature of the card is ambiguous when viewed with one eye: When the card is perceived as concave, the side farther from the illumination suddenly appears darker than it does when the card is perceived as convex. [Ernst Mach]

Mach scale

Mach scale a measurement of the degree to which individuals condone, tolerate, or condemn the use of manipulation and deceit in pursuit of material or other aims. Persons low in Mach (or Machiavellianism) affirm absolute ethical standards; persons high in this quality reveal relative and shifting standards of behavior.

Mach–Dvorak stereoillusion

Mach–Dvorak stereoillusion an illusion of depth in the motion of a stimulus that moves only in two dimensions, such as a pendulum. The illusion is induced by allowing one eye to view the motion before the other eye and never allowing both eyes to view the motion at the same time. The delay between the signals from the two eyes is interpreted by the visual system as binocular disparity, a normal depth cue. Compare Pulfrich effect. [Ernst Mach; Vinko Dvorak (1848–1922), Czech physicist]

Machian positivism

Machian positivism the subjectivist form of positivism developed by Ernst Mach. Mach held, with other positivists, that sensory experience is the touchstone of knowledge; however, unlike most other positivists, he held that sensations do not faithfully represent the reality of an external world. Thus, from this antirealist perspective, empirical knowledge is subjective.

Machiavellian hypothesis

Machiavellian hypothesis the hypothesis that the evolution of intelligence, especially in its social aspects, was largely dependent on behavior characterized by a desire and striving for power. According to the hypothesis, individuals who are more Machiavellian in their behavior are more likely to be successful in adaptation and thus more likely to spread their genes to future generations. [Niccolò Machiavelli (1469–1527), Italian political theorist]

Machiavellianism

Machiavellianism n. a personality trait marked by a calculating attitude toward human relationships and a belief that ends justify means, however ruthless. A Machiavellian is one who views other people more or less as objects to be manipulated in pursuit of his or her goals, if necessary through deliberate deception. [Niccolò Machiavelli, who argued that an effective ruler must be prepared to act in this way]

machine consciousness

machine consciousness 1. functions simulated by computers or robots as a way of modeling and investigating the behavioral, cognitive, and neural components of human consciousness. 2. an artificial system (e.g., robot) constructed to have phenomenal consciousness (called artificial consciousness). 3. broadly, the entire interdisciplinary research effort behind both aforementioned senses, involving such areas as artificial intelligence, robotics, computer science, cybernetics, cognitive science, cognitive psychology, philosophy of mind, and neuroscience. See also Chinese Room argument; Turing test.

Machover Draw-a-Person Test (DAP Test)

Sorry, "machover-draw-a-person-test-dap-test" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mAChR

mAChR abbreviation for muscarinic receptor.

MacLean’s theory of emotion

MacLean’s theory of emotion an extension of Papez’s theory of emotion emphasizing the importance of all parts of the limbic system, especially the hippocampus and amygdala, in the control of emotional experience. Also called Papez–MacLean theory of emotion. See also Cannon–Bard theory. [Paul D. MacLean (1913–2007), U.S. physician and neuroscientist]

macro- (macr-)

Sorry, "macro-macr" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

macrobiotics

macrobiotics n. a theory of nutrition that is based on achieving balance and harmony between foods that are classified, according to the Chinese concept, as either yin or yang (see yin and yang). Macrobiotic diets consist mainly of whole grains and vegetables, with fruit and occasional fish; animal products are avoided. Food is prepared and cooked in particular ways to preserve the yin and yang characteristics. [introduced to the West by Japanese educator George Ohsawa (1893–1966)]

macrocephaly

macrocephaly n. a head circumference that is more than two standard deviations above the mean for age, gender, race, and gestation. Although it can be caused by hydrocephalus or megalencephaly, it does not necessarily indicate abnormality. Benign familial macrocephaly describes a genetic tendency toward large head size that does not result in cognitive or neurological impairment. Compare microcephaly. —macrocephalic adj.

macroelectrode

macroelectrode n. a conductor of electrical current usually with a diameter of a millimeter or more, used, for example, to stimulate or record from tissue. Compare microelectrode.

macroergonomics

macroergonomics n. an approach to ergonomics that examines any given work system from a broad perspective in which all of its various elements—physical, organizational, environmental, and cognitive—are given due consideration. Compare microergonomics. See also sociotechnical systems approach; systems engineering.

macroglia

macroglia n. a relatively large type of nonneuronal central nervous system cell (glia), including astrocytes, ependymal cells, and oligodendrocytes. —macroglial adj.

macroglossia

macroglossia n. an abnormally large tongue, affecting the production of lingual sounds in speech.

macrogyria

macrogyria n. see lissencephaly.

macromastia

macromastia n. abnormally large breasts in a female.

macropsia

macropsia n. a visual illusion in which an object appears to be larger than it is in reality. Also called megalopsia. See also metamorphopsia. Compare micropsia.

macroskelic

macroskelic adj. denoting a constitutional type of body build in which the most prominent characteristic is abnormally long legs. The macroskelic individual would be classified as the asthenic type in Kretschmer typology.

macrosplanchnic type

macrosplanchnic type a body type in which the trunk is disproportionately large compared with the limbs. Also called macrosplanchnic build. [described by Italian physician Giacinto Viola (1870–1943)]

macrosystem

macrosystem n. 1. in ecological systems theory, the level of environmental influence that is most distal to the developing individual and that affects all other systems. It includes the values, traditions, and sociocultural characteristics of the larger society. Compare chronosystem; exosystem; mesosystem. [introduced by Urie Bronfenbrenner] 2. in sociology, any social system or structure.

macula

macula n. (pl. maculae) 1. in hearing, a patch of sensory tissue in the utricle and saccule of the inner ear that provides information about the position of the body in relation to gravity. The macula contains sensory hair cells whose processes (stereocilia) are embedded in a gelatinous matrix (cupula) containing calcareous particles (otoliths). When the orientation of the head changes, the relatively dense otoliths respond to gravity, causing the gelatinous mass to shift and the stereocilia to flex. This triggers nerve impulses in the hair-cell fibers, which act as signals to the brain. 2. in vision, see macula lutea.

macula lutea

macula lutea a small spot in the retina that is in direct alignment with the optics of the eye. It contains a yellow pigment and a central depression, the fovea centralis. Also called macula.

macular degeneration

macular degeneration dystrophy of the macula lutea, which affects both eyes and causes progressive loss of central vision. Macular degeneration occurs at various ages from birth to old age. Age-related macular degeneration is among the most common causes of visual impairment in older people, with an incidence of about 5% in those ages 55 to 64 and up to about 45% in those ages 75 to 84. There are two types: exudative (or wet) macular degeneration, in which blood vessels grow under the retina and hemorrhage in the area of the macula; and atrophic (or dry) macular degeneration, in which one of the retinal layers degenerates or atrophies. Apart from age, other risk factors for the disease include exposure to ultraviolet light, smoking, hypertension, and possibly zinc deficiency in the diet.

macular sparing

macular sparing see visual field sparing.

macular splitting

macular splitting see visual field sparing.

maculopathy

maculopathy n. damage to the macula lutea, resulting in deterioration of visual acuity. It is caused by leakage from abnormal retinal capillaries, leading to the formation of hard exudate and edema.

Mad Hatter’s disease

Mad Hatter’s disease a condition caused by chronic mercury poisoning and characterized by changes in mental status, emotional disturbance, gastrointestinal disturbances, and weakness or partial paralysis of the legs. The condition may also cause psychosis, behavioral changes, erethism, and several other symptoms. The name derives from the prevalence of this condition among hatters whose occupation, until the mid-20th century, exposed them to vapors from the mercury used to treat felt for hats. Also called Mad Hatter’s syndrome.

MADD

MADD abbreviation for Mothers Against Drunk Driving.

Maddox rod test

Maddox rod test a test of eye-muscle balance. The individual views a light source through glass rods, which convert it into a line of light: The differential images perceived by the two eyes indicate the degree of heterophoria. [Ernest Edmund Maddox (1860–1933), British ophthalmologist]

madness

madness n. an obsolete name for mental illness or for legal insanity.

MAE

MAE 1. abbreviation for motion aftereffect. 2. abbreviation for Multilingual Aphasia Examination.

MAF

MAF abbreviation for minimal audible field.

magazine training

magazine training in operant conditioning, the training needed to familiarize an experimental animal with the mechanism (usually a feeder) that delivers the reinforcer.

magic

magic n. 1. a system of practices in which humans attempt to manipulate natural or supernatural forces through such means as rituals, incantations, and spells. Magic had an important social role in many prescientific societies, where its practitioners often held great power and authority. In the modern world, magical belief has survived most obviously as an underground esoteric tradition (see occult) but also in many popular superstitions and New Age practices. Magical rituals can be said to differ from religious rituals in that they involve a direct attempt to control certain physical facts (e.g., the weather), as opposed to a supplication to a higher power or powers. 2. in some individuals with obsessive-compulsive disorder, attempts to allay anxiety by invoking certain numbers or performing certain rituals. See also magical thinking. —magical adj.

magic circle

magic circle a group technique mostly used with children, who gather in a circle and discuss personal issues and concerns. A variation for use in school was developed by U.S. psychiatrist William Glasser (1925–2013) to increase motivation for learning.

magic mushroom

magic mushroom see psilocin.

magical number

magical number see seven plus or minus two.

magical thinking

magical thinking the belief that events or the behavior of others can be influenced by one’s thoughts, wishes, or rituals. Magical thinking is typical of children up to 4 or 5 years of age, after which reality thinking begins to predominate. See also thought–action fusion.

MAGL

MAGL abbreviation for monoacylglycerol lipase. See endogenous cannabinoid.

magnetic resonance imaging (MRI)

Sorry, "magnetic-resonance-imaging-mri" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

magnetic sense

magnetic sense the ability of an organism to orient itself according to the lines of force of a magnet or the magnetic fields of the earth. Some migrating birds tend to follow magnetic fields of the earth with the aid of a sensory apparatus that detects the force of magnetism. Homing pigeons use their magnetic sense as a backup system when solar cues for navigation are lacking, for example, on overcast days.

magnetic source imaging (MSI)

Sorry, "magnetic-source-imaging-msi" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

magnetoencephalography (MEG)

Sorry, "magnetoencephalography-meg" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

magnification factor

magnification factor see cortical magnification factor.

magnification power

magnification power see focusing power.

magnitude effect

magnitude effect see behavioral economics.

magnitude estimation

magnitude estimation a psychophysical procedure in which participants make subjective judgments of the magnitude of stimuli by assigning them numerical values along a 7- or 10-point scale. The resulting scales often follow a power law (see Stevens law).

magnitude of effect

magnitude of effect see effect size.

magnitude production

magnitude production a direct scaling procedure in which the observer is provided with a number representing the magnitude of a stimulus and is required to adjust the stimulus to produce a sensation that corresponds to this number with reference to a standard stimulus to which a magnitude number has also been assigned. Also called production method.

magnitude scaling of attitudes

magnitude scaling of attitudes a procedure for measuring attitudes and other constructs by representing them as physical stimuli. Participants indicate their attitudes by regulating some perceptual property of a stimulus, such as the brightness of a light, the length of a line, or the pitch of a tone. For example, they might indicate their evaluation of an object by turning a brightness dial on a light, with no light representing an extremely negative attitude and maximum brightness representing an extremely positive attitude. This procedure usually involves reporting the attitude on two different perceptual properties and then validating the measurement procedure by confirming that the mathematical relationship between these two modalities is close to established numerical values for the specific modalities. [primarily developed by U.S. political scientist Milton G. Lodge (1936– )]

magnocellular system

magnocellular system the part of the visual system that projects to or originates from large neurons in the two most ventral layers (the magnocellular layers) of the lateral geniculate nucleus. It allows the rapid perception of movement, form, and changes in brightness but is relatively insensitive to stimulus location and color. See also M-cell. Compare parvocellular system.

main clause

main clause see clause.

main diagonal

main diagonal the line of values running from the upper left to the lower right of a square matrix. The first value in the main diagonal is the number in the first row and the first column of the matrix, the second value is the number in the second row and second column, and so on.

main effect

main effect the consistent total effect of a single independent variable on a dependent variable over all other independent variables in an experimental design. It is distinct from, but may be obscured by, an interaction effect between variables.

mainlining

mainlining n. slang for taking illicit drugs by intravenous injection. See intravenous drug use. —mainliner n.

mainstreaming

mainstreaming n. 1. the placement of children with disabilities into regular classroom environments on a part-time basis, such that they attend only some regular education classes during the school day and spend the remaining time in special education classes. The aim is to offer each child the opportunity to learn in an environment that has the highest probability of facilitating rehabilitation efforts and supporting academic growth, although some critics have denounced the practice as requiring that children with disabilities “earn” their opportunity to participate in a regular classroom. See also full inclusion; least restrictive environment. 2. the return of recovered or deinstitutionalized patients to the community, where they receive rehabilitative assistance to help them achieve as full and normal a life as possible.

maintaining cause

maintaining cause an influence in a person’s environment that tends to maintain and reinforce maladaptive behavior. An example is the required participation at cocktail parties of a business professional with alcoholism.

maintenance function

maintenance function any of the processes that keep an organism’s physiological activities in homeostasis.

maintenance rehearsal

maintenance rehearsal repeating items over and over to maintain them in short-term memory, as in repeating a telephone number until it has been dialed (see rehearsal). According to the levels-of-processing model of memory, maintenance rehearsal does not effectively promote long-term retention because it involves little elaboration of the information to be remembered. Also called rote rehearsal. See also phonological loop.

maintenance therapy

maintenance therapy treatment or therapy designed to maintain patients in a stable condition and to promote gradual healing or prevent relapse. It usually (but not always) refers to maintenance drug therapy (maintenance pharmacotherapy or prophylactic maintenance). Drug therapy is generally divided into three phases—acute, continuation, and maintenance—roughly corresponding to intervals of 1 month, 6 months, and a year or longer. Patients who respond in the acute and continuation phases may be placed on maintenance pharmacotherapy in the hopes of preventing relapse. Drugs that may be used for maintenance include methadone (see methadone maintenance therapy), buprenorphine, antipsychotics, lithium, and antidepressants. Prophylactic maintenance alone, however, does not eliminate relapse; for several conditions, evidence suggests that psychotherapy must also be included to minimize relapse. Although maintenance therapy is often continued indefinitely, patients should be periodically reassessed to determine if such treatment is still necessary.

major depressive disorder

major depressive disorder in DSM–IV–TR and DSM–5, a mood disorder characterized by persistent sadness and other symptoms of a major depressive episode but without accompanying episodes of mania or hypomania or mixed episodes of depressive and manic or hypomanic symptoms. Also called major depression.

major depressive episode

major depressive episode in DSM–IV–TR, a period in which an individual experiences anhedonia or is persistently sad, pessimistic, or otherwise overly negative. Additional symptoms include poor or increased appetite with significant weight loss or gain; insomnia or excessive sleep; psychomotor agitation or psychomotor retardation; loss of energy with fatigue; feelings of worthlessness or inappropriate guilt; reduced ability to concentrate or make decisions; and recurrent thoughts of death, suicidal ideation, or attempted suicide. DSM–5 retains these same symptomatic criteria but has removed its predecessor’s qualified exclusion of bereavement with respect to major depressive episode and replaced it with a broader advisory (see bereavement exclusion). One or more major depressive episodes are a characteristic feature of major depressive disorder and bipolar disorder.

major histocompatibility complex (MHC)

Sorry, "major-histocompatibility-complex-mhc" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

major neurocognitive disorder

major neurocognitive disorder in DSM–5, a new diagnosis combining and replacing dementia and amnestic disorder.

major tranquilizer

major tranquilizer see antipsychotic.

majority influence

majority influence social pressure exerted by the greater part of a group on individual members and smaller factions within the group. The majority tends to push for conformity and stability, and members usually respond to this either by accepting the majority’s position as their own (conversion) or by conforming publicly but retaining their own position privately (compliance). Compare minority influence.

majority vote technique

majority vote technique in parapsychology experiments, a technique in which the participant makes several “calls,” or guesses, about a single target, the most frequent being considered the participant’s response.

majority-minority

majority-minority see minority group.

mal de ojo

mal de ojo a culture-bound syndrome, reported in many Mediterranean regions, that is characterized by fever, sleep disturbances, and gastrointestinal problems. It most commonly affects children; the Spanish name translates to evil eye.

mal de pelea

mal de pelea a culture-bound syndrome found in Puerto Rico that is similar to amok. Individuals experience a period of brooding and then suddenly become violent and attack others around them (the Spanish name literally means “fighting sickness”). Also called Puerto Rican syndrome.

mal puesto

mal puesto see rootwork.

mal-

Sorry, "mal" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

maladaptation

maladaptation n. a condition in which biological traits or behavior patterns are detrimental, counterproductive, or otherwise interfere with optimal functioning in various domains, such as successful interaction with the environment and effectual coping with the challenges and stresses of daily life. Compare adaptation. —maladaptive adj.

maladjustment

maladjustment n. 1. inability to maintain effective relationships, function successfully in various domains, or cope with difficulties and stresses. 2. any emotional disturbance of a relatively minor nature. —maladjusted adj.

malaise

malaise n. a vague feeling of general illness, discomfort, or uneasiness.

malapropism

malapropism n. a linguistic error in which one word is mistakenly used for another having a similar sound, often to ludicrous effect, as in She was wearing a cream casserole (for camisole) or I can’t eat pasta without marzipan (for parmesan). The term is named for Mrs. Malaprop, a character in Richard Brinsley Sheridan’s play The Rivals (1775), whose speech is full of preposterous errors of this kind.

Malcolm horizon

Malcolm horizon an improvement in flight instruments, based on ergonomic principles, in which the ground representation of the display is extended across the cockpit. This makes it easier to detect small angular motions. [Richard Malcolm, Canadian aviator]

maldevelopment

maldevelopment n. the abnormal development of an individual because of genetic, dietary, or external factors.

male chauvinism

male chauvinism see chauvinism.

male climacteric

male climacteric a hypothetical period in some men’s lives that has been compared to female menopause (see climacteric). Also known as male menopause, it occurs some 10 years later than in women and appears to be associated with declines in the levels of various hormones, such as testosterone. Symptoms, when they occur, include fatigue, problems with memory and concentration, decreased sexual desire, erectile dysfunction, and (in some cases) depression. Also called andropause; male climacterium. See also gonadopause.

male continence

male continence see coitus reservatus.

male erectile disorder

male erectile disorder in DSM–IV–TR, persistent or recurrent inability in a man to achieve or maintain an erection adequate to complete the sex act. It causes marked distress and impairment of interpersonal relations and is not due to the physiological effects of a physical disorder, medication, or a substance of abuse. The disorder may be lifelong or acquired and either situational (occurring only in certain situations or with certain partners) or generalized (occurring in all situations). It is called erectile disorder in DSM–5. See also erectile dysfunction; impotence.

male genitalia

male genitalia see genitalia.

male homosexual prostitution

male homosexual prostitution sexual contact between males for the financial or other gain of one of the participants. Studies indicate that a social hierarchy exists among male prostitutes, as among female prostitutes. Lowest in status are the street hustlers, who are usually teenage boys and not necessarily gay themselves; next are the bar hustlers; and highest in prestige are the call boys, who do not solicit in public.

male hypoactive sexual desire disorder

male hypoactive sexual desire disorder see hypoactive sexual desire disorder.

male menopause

male menopause see male climacteric.

male orgasmic disorder

male orgasmic disorder in DSM–IV–TR, persistent or recurrent delay in, or absence of, male orgasm during sexual stimulation that produces arousal. The man’s age and the quality and duration of stimulation are considered in making this diagnosis, which does not apply if the condition is due only to the effects of drugs, medications, or medical conditions. It is identified as delayed ejaculation in DSM–5. Sometimes also called retarded ejaculation.

male pseudohermaphroditism

male pseudohermaphroditism see androgen-insensitivity syndrome.

male–male competition

male–male competition in species in which the operational sex ratio leads to more reproductively active males than females, the rivalry that ensues as males compete over which will be able to mate with receptive females. In some species, such as cooperative-breeding mammals, male parental care is a limiting resource to female reproduction, and there is extensive female–female competition.

maleness

maleness n. the quality of being male in the anatomical and physiological sense by virtue of possessing the XY combination of sex chromosomes. Compare masculinity.

malevolent transformation

malevolent transformation the feeling that one lives among enemies and can trust no one. This attitude, purported to be the result of harsh or unfair treatment during childhood, has been posited to be the basis for social withdrawal, hostility, and, in some cases, mental disorder of a persecutory nature. [first described by Harry Stack Sullivan]

malformation

malformation n. any abnormality of structure: a deformity.

malfunction

malfunction n. failure to work properly.

mali-mali

mali-mali n. a culture-bound syndrome found in the Philippines, with symptoms similar to those of latah.

malice aforethought

malice aforethought the mental elements of premeditation and deliberation or extreme disregard for human life that are required for a person to be convicted of first-degree murder.

malignant

malignant adj. 1. describing a disorder that gets progressively worse or is resistant to treatment, eventually causing death. 2. describing a tumor that invades and destroys tissues and may also spread to other sites (i.e., undergo metastasis). Compare benign.

malignant hypertension

malignant hypertension see hypertension.

malingering

malingering n. the deliberate feigning of an illness or disability to achieve a particular desired outcome. For example, it may take the form of faking mental illness as a defense in a trial, faking physical illness to win compensation, or faking an injury or misinforming people of one’s state of rehabilitation to avoid practicing or playing sport. Malingering is distinguished from factitious disorder in that it involves a specific external factor as the motivating force. —malingerer n.

malleation

malleation n. a spasmodic tic in which the hands twitch in a hammering motion against the thighs.

malleus

malleus n. see ossicles.

malnutrition

malnutrition n. a state characterized by an unhealthy balance of carbohydrates, fats, proteins, vitamins, and minerals in the diet. Malnutrition may be due to excessive intake of certain food categories, as in obesity and hypervitaminosis (see vitamin A toxicity; vitamin D toxicity), or inadequate food intake. Dietary deficiencies play a role in many physical and psychological disorders. For example, nicotinic acid deficiency is marked by depression and other mental disturbances (see pellagra). Research suggests that mild nutritional deficiencies have little, if any, effect on intelligence but that moderate and (especially) severe deficiencies can result in intellectual deficits. See also kwashiorkor; marasmus; thiamine; vitamin deficiency.

malpractice

malpractice n. professional misconduct or negligent behavior on the part of a practitioner (e.g., psychotherapist, psychiatrist, doctor, lawyer, financial adviser) that may lead to legal action.

Malthusian theory

Malthusian theory the doctrine proposed by British economist Thomas Malthus (1766–1834) that exponential increases in population growth would surpass arithmetical increases in food supply with dire consequences, unless population growth was arrested by such means as famine, war, or the control of reproduction through moral restraint. In the Western world, Malthus was proved wrong owing to increased prosperity from industrialization. However, his analysis has remained influential (see neo-Malthusian). Also called Malthusianism; Malthus theory.

maltreatment

maltreatment n. the abuse or neglect of another person, which may involve emotional, sexual, or physical action or inaction, the severity or chronicity of which can result in significant harm or injury. Maltreatment also includes such actions as exploitation and denial of basic needs (e.g., food, shelter, medical attention).

malum

malum n. a painful degenerative state of a joint as a result of aging.

malum in se

malum in se in law, an action that is considered wrong because it is “evil in itself,” such as murder. Compare malum prohibitum.

malum prohibitum

malum prohibitum in law, an action that is considered wrong because it is against the law, such as driving without a valid license. Compare malum in se.

mammalingus

mammalingus n. the act of suckling the breast during sexual intercourse, particularly in terms of the concept, proposed by British psychoanalyst Ernest Jones (1879–1958), that the act represents a type of fellatio. Mammalingus is distinguished from the normal interest and pleasure derived from caressing or orally stimulating the breasts as a part of sexual activity.

mammary gland

mammary gland any of the glands in female mammals that secrete milk. In humans, the mammary glands are called breasts.

mammillary body

mammillary body either of a pair of small, spherical nuclei at the base of the brain, slightly posterior to the infundibulum (pituitary stalk), that are components of the limbic system. Also called corpus mammillare.

mammillothalamic tract

mammillothalamic tract the tract that connects the mammillary bodies to the thalamus at the base of the brain.

mammography

mammography n. a diagnostic procedure that uses low-dose X-ray photography to detect breast tumors or other abnormalities, either noncancerous (benign) or cancerous (malignant). The X-ray negative produced is called a mammogram.

man–machine system

man–machine system see human–machine system.

managed behavioral health organization (MBHO)

Sorry, "managed-behavioral-health-organization-mbho" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

managed care

managed care any system of health care delivery that regulates the use of member benefits to contain expenses. The term originally referred to prepaid health plans (e.g., HMOs) but is now applied to many different kinds of reimbursement and utilization review mechanisms. It is also used to denote the organization of health care services and facilities into groups to increase cost-effectiveness. Managed care organizations (MCOs) include HMOs, PPOs (preferred provider organizations), point-of-service plans (POSs), exclusive provider organizations (EPOs), physician–hospital organizations (PHOs), integrated delivery systems (IDSs), and independent practice associations (IPAs).

management by objectives (MBO)

Sorry, "management-by-objectives-mbo" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

management development

management development programs used to improve the effectiveness with which people in managerial or executive positions perform their roles. Management development can involve a variety of interventions, including classroom training, counseling, mentoring, and executive coaching as well as business games and other role-play techniques. See also organizational development; personnel training.

management fashion

management fashion management practices that are currently popular but not necessarily well-grounded in either theory or practice. [defined in 1996 by U.S. management theorist Eric Abrahamson (1958– )]

management information systems (MIS)

Sorry, "management-information-systems-mis" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

management psychology

management psychology see managerial psychology. See also industrial and organizational psychology.

management-simulation game

management-simulation game see business game.

managerial grid

managerial grid see Blake–Mouton managerial grid.

managerial psychology

managerial psychology the application of a knowledge of human behavior to issues that arise in the management of organizations, especially with regard to decision making, problem solving, leadership, and human relations in the workplace. Although often used synonymously with industrial and organizational psychology, the term suggests an approach that adopts the perspective of the employer. Also called management psychology.

MANCOVA

MANCOVA acronym for multivariate analysis of covariance.

mand

mand n. in linguistics, a category of utterances in which the speaker makes demands on the hearer, as in Listen to me or Pass the salt, please. According to the behaviorist analysis of language, this form of verbal behavior is reinforced by the compliance of the listener. See behaviorism. [coined by B. F. Skinner from command and demand]

mandate phenomenon

mandate phenomenon a tendency for leaders to overstep the bounds of their authority when they feel they have the overwhelming support of the group. As the number of people favoring a particular person for leadership increases, that leader is less likely to anticipate criticism for his or her actions, is less concerned about dissenting others, and may even attach invulnerability to his or her decisions.

mandated reporting

mandated reporting the legal requirement in the United States that psychologists and other human services personnel (e.g., social workers, nurses) report any suspected or known cases of abuse or neglect of a child, a dependent adult, or an older person. Those who fail to report such cases may be subject to legal and professional sanctions.

mandibular reflex

mandibular reflex see jaw jerk.

mandibulofacial dysostosis

mandibulofacial dysostosis see Treacher Collins syndrome.

mandrake

mandrake n. the root or other parts of the plant Mandragora officinarum, traditionally used as an anesthetic, aphrodisiac, hallucinogen, and folk remedy for asthma, whooping cough, stomach ulcers, and other conditions. The name derives from the supposed resemblance of the root to the human form; -drake (from the Old English word for dragon) alludes to the alleged magical powers of the plant. A member of the nightshade family, it contains the anticholinergic alkaloids scopolamine, mandragorine, and hyoscyamine, which are poisonous and potentially fatal. Symptoms of poisoning include flushing, pupillary dilation, dry mucous membranes, and dry mouth, progressing to visual disturbances, hallucinations, restlessness, agitation, delirium, and possibly death from respiratory failure.

mania

mania n. 1. generally, a state of excitement, overactivity, and psychomotor agitation, often accompanied by overoptimism, grandiosity, or impaired judgment. 2. more specifically, a manic episode or, sometimes, a hypomanic episode. 3. preoccupation with a particular activity or idea, especially when used as a suffix (e.g., kleptomania, pyromania).

mania a potu

mania a potu see idiosyncratic intoxication.

maniac

maniac n. 1. a lay term for a mentally or emotionally disturbed person, particularly one who is considered dangerous to others. 2. an obsolete name for a person who experiences mania.

manic

manic 1. adj. relating to mania. 2. n. an obsolete name for a person experiencing a manic episode.

manic episode

manic episode a period characterized by elevated, expansive, or irritable mood, often with several of the following symptoms: an increase in activity or psychomotor agitation; talkativeness or pressured speech; flight of ideas or racing thoughts; inflated self-esteem or grandiosity; a decreased need for sleep; extreme distractibility; and intense pursuit of activities that are likely to have unfortunate consequences (e.g., buying sprees, sexual indiscretions). In DSM–IV–TR and DSM–5, a distinguishing criterion between a manic and a hypomanic episode is their duration, with manic episodes lasting at least a week and hypomanic episodes lasting at least 4 consecutive days. One or more manic episodes are characteristic of bipolar disorder. See also mixed episode.

manic-depressive illness

manic-depressive illness see bipolar disorder.

manifest anxiety

manifest anxiety in psychoanalysis, anxiety with overt symptoms that indicate underlying emotional conflict or repression.

Manifest Anxiety Scale

Manifest Anxiety Scale see Children’s Manifest Anxiety Scale; Taylor Manifest Anxiety Scale.

manifest content

manifest content 1. the matter that is overtly expressed and consciously intended in any utterance or other form of communication. 2. in psychoanalytic theory, the images and events of a dream or fantasy as experienced and recalled by the dreamer or fantasist, as opposed to the latent content, which is posited to contain the hidden meaning. See also dream analysis; dream censorship; dream-work.

manifest goal

manifest goal in evaluation research, an openly stated, objectively defined goal of an organization or program. Manifest goals are specified by indicators of success and assessed in an evaluation program. Compare latent goal.

manifest variable

manifest variable a variable whose values can be directly observed or measured, as opposed to one whose values must be inferred. In structural equation modeling and factor analysis, manifest variables are used to study latent variables. Also called indicator variable.

manifestation

manifestation n. an observable expression, indication, or sign of a physical or psychological condition.

manipulandum

manipulandum n. (pl. manipulanda) an object designed to be manipulated in a psychological test or experiment.

manipulation

manipulation n. 1. behavior designed to exploit, control, or otherwise influence others to one’s advantage. 2. in an experimental design, the researcher’s adjustment of an independent variable such that one or more groups of participants are exposed to specific treatments while one or more other groups experience a control condition. For example, a health researcher could introduce a manipulation so that a portion of the participants in a study randomly receive a new drug, whereas the remaining participants receive only a placebo. See experimental variable.

manipulation check

manipulation check any means by which an experimenter evaluates the efficacy of an experimental variable, that is, verifies that a manipulation affected the participants as intended.

Mann–Whitney U test

Mann–Whitney U test a nonparametric test of centrality for ordinal data that contrasts scores from two independent samples to assess whether there are significant differences between the two sets of rankings. The statistic obtained from this test, U, is calculated by summing the number of ranks in one group that are smaller than each of the ranks in the other group. A Mann–Whitney U test is analogous to a one-way analysis of variance, except that the former is conducted with ranked data and the latter is conducted with continuous data. See also Wilcoxon–Mann–Whitney test. [Henry Berthold Mann (1905–2000), Austrian-born U.S. mathematician; Donald Ransom Whitney (1915–2001), U.S. statistician]

mannerism

mannerism n. a gesture, facial expression, or verbal habit peculiar to the individual.

manners

manners pl. n. respectful, polite, and socially acceptable ways of behaving. Codes of manners vary greatly from one culture to another and may also vary between classes or subcultures in a society.

manning theory

manning theory see staffing theory.

manoptoscope

manoptoscope n. a hollow cone used for measuring eye dominance. The observer views a small target by placing the base of the cone near the eyes and then viewing the target through the small end of the cone while closing first one eye and then the other. The eye through which the target is actually seen is the dominant eye.

MANOVA

MANOVA acronym for multivariate analysis of variance.

mantle layer

mantle layer in neuroanatomy, the middle layer of the embryonic neural plate, which develops into cerebral gray matter.

mantra

mantra n. 1. in Hinduism and Buddhism, a sacred utterance, such as a syllable, phrase, or hymn (often in Sanskrit). 2. any verbal formula used for spiritual, religious, or meditative purposes to help block out extraneous thoughts and induce a state of relaxation that enables the individual to reach a deeper level of consciousness. See also concentrative meditation; transcendental meditation. Compare yantra.

manual arts therapy

manual arts therapy training in industrial arts, such as woodworking and metalworking, for therapeutic purposes as part of the rehabilitation process. See also occupational therapy.

manual communication

manual communication communication with the hands rather than by speech. Manual communication encompasses sign language and fingerspelling and is used primarily with or between people who are deaf or have severe hearing loss.

manual dominance

manual dominance see handedness.

manual-assisted therapy

manual-assisted therapy see manualized therapy.

manual-based therapy

manual-based therapy see manualized therapy.

manual-control effects

manual-control effects in the manual control of aircraft or spacecraft, the effects on human performance of the nature and complexity of the task, G forces (acceleration levels), and the aerodynamic characteristics of the vehicle.

manualism

manualism n. a method of instruction for people with severe hearing impairment that depends on the use of sign language and fingerspelling for communication. Also called manual method.

manualized therapy

manualized therapy interventions that are performed according to specific guidelines for administration, maximizing the probability of therapy being conducted consistently across settings, therapists, and clients. Also called manual-assisted therapy; manual-based therapy.

MAO

MAO abbreviation for monoamine oxidase.

MAOI (MAO inhibitor)

Sorry, "maoi-mao-inhibitor" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

MAP

MAP 1. abbreviation for minimal audible pressure. 2. abbreviation for modal action pattern.

map-tracing test

map-tracing test a test of the ability to visualize spatial relations and to orient oneself in space. It is used, for example, to test a pilot’s ability to distinguish up from down when no obvious reference point, such as the horizon, is available.

maple-syrup urine disease (MSUD)

Sorry, "maple-syrup-urine-disease-msud" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

maprotiline

maprotiline n. a tetracyclic antidepressant closely related to the tricyclic antidepressants. Like the tricyclic agents, it can cause adverse anticholinergic effects and serious disturbances in heart rhythm; its use has therefore declined, and it is rarely encountered in modern clinical practice. U.S. trade name: Ludiomil.

MAR

MAR abbreviation for missing at random.

marasmus

marasmus n. a condition (from Greek marasmos, “consumption”), usually occurring in infancy, that is characterized by apathy, withdrawal, and emaciation resulting from severe malnutrition. If left untreated, it can result in delayed physical and cognitive development and, in some cases, death. Marasmus tends to occur mostly in developing countries, often as a result of famine, premature or abrupt weaning, or vitamin insufficiency due to limitations in food variety. It can, however, occur in developed nations as well—for example, in children living in poor rural and urban areas, children with chronic disease, and children who are institutionalized. See also kwashiorkor.

marathon group

marathon group an encounter group that meets in seclusion for a single extended session, usually varying from 6 hours to several days, on the theory that this will elicit more intense interactions, foster a greater sense of intimacy and sharing, and encourage a freer expression of feelings as the time elapses than would a series of shorter, interrupted sessions. Such groups are often organized around addressing a single issue or related set of issues. See also time-extended therapy.

Marbe’s law

Marbe’s law in word-association tests, the finding that the speed of making an association is proportional to the number of people who make that association. [Karl Marbe (1869–1953), German psychologist]

marche à petits pas

marche à petits pas a shuffling, progressively accelerating gait commonly seen in Parkinson’s disease. See festinating gait. [French, literally: “walking in little steps”]

Marfan’s syndrome

Marfan’s syndrome an autosomal dominant disorder (see dominant allele) of the connective tissue in the body, affecting the blood vessels, skeleton, and eyes. Common symptoms of the disorder include an unusually tall frame, long fingers and toes, loose joints, curvature of the spine, protruding breastbone (pectus carinatum), and dislocation of the lens of the eye. The aorta of the heart may also be enlarged, and there may be leakage in the aortal valve. [Antoine Bernard-Jean Marfan (1858–1942), French pediatrician]

margin of error (MOE)

Sorry, "margin-of-error-moe" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

marginal

marginal 1. adj. borderline or on the periphery. 2. n. in statistics, see marginal frequency.

marginal consciousness

marginal consciousness contents of consciousness that are not at the center of attention. Marginal stimuli are not equivalent to subliminal stimuli. See fringe consciousness; subliminal perception.

marginal frequency

marginal frequency the sum of any one of the rows or columns in a data matrix. For example, in a table of students classified by sex and area of study, the number of female students, regardless of area of study, would be one marginal frequency, and the number of students enrolled in a specific area of study, regardless of sex, would be another.

marginal group

marginal group in a relatively homogeneous country or community, a distinct group that is not assimilated into the social mainstream because it differs (or is viewed as differing) in one or more significant ways, as in its religious or cultural beliefs. Also called marginalized group.

marginal intelligence

marginal intelligence an intelligence level between average and mental disability.

marginal sulcus

marginal sulcus a branch of the cingulate sulcus that turns upward between the paracentral lobule and superior frontal gyrus on the surface of each cerebral hemisphere.

marginal value theorem

marginal value theorem a part of optimal foraging theory that predicts when an organism should leave one food source and travel to the next. Decisions are based on the benefits and costs of staying in a location where food sources are known but declining compared with the costs and benefits of traveling to a new, unknown food source. In experimental work, the time and effort needed to travel to a new area appears to regulate how long animals remain foraging in the current area.

marginalization

marginalization n. a reciprocal process through which an individual or group with distinctive qualities, such as idiosyncratic values or customs, becomes identified as one that is not accepted fully into the larger group. See also acculturation strategies. —marginalize vb.

marianismo

marianismo n. in many Latin American or Hispanic cultures, an idealized traditional feminine gender role characterized by submissiveness, selflessness, chastity, hyperfemininity, and acceptance of machismo in males. Although clearly derived from the traditional ideal of the Virgin Mary, marianismo is not to be confused with a specific religious practice of the Roman Catholic Church.

marijuana (marihuana)

Sorry, "marijuana-marihuana" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

Marinesco–Sjögren syndrome

Marinesco–Sjögren syndrome an autosomal recessive hereditary disorder marked by cataracts, short stature, cerebellar ataxia (incoordination of voluntary movements), and mild to moderate intellectual disability. Affected individuals may live well past middle age but often lose their ability to walk because of progressive muscle weakness. [reported in the 1930s by Georges Marinesco (1864–1938), Romanian neurologist, and Torsten Sjögren (1896–1974), Swedish physician]

Marinol

Marinol n. a trade name for dronabinol. See tetrahydrocannabinol.

marital adjustment

marital adjustment the process by which married couples attain mutual gratification and achieve common goals while maintaining an appropriate degree of individuality. Especially important to marital adjustment are (a) the sharing of experiences, interests, and values; (b) respect for the partner’s individual needs, aims, and temperament; (c) maintenance of open lines of communication and expression of feeling; (d) clarification of roles and responsibilities; (e) cooperation in decision making, problem solving, and rearing of children; and (f) attainment of mutual sexual gratification.

marital conflict

marital conflict open or latent antagonism between marriage partners. The nature and intensity of conflicts varies greatly, but studies indicate that the prime sources are often sexual disagreement, child-rearing differences, temperamental differences (particularly the tendency of one partner to dominate), and, to a lesser extent, religious differences, differences in values and interests, and disagreements over money management.

marital counseling

marital counseling see marriage counseling.

marital schism

marital schism a condition of open discord between marital partners that puts a strain on the marriage and may lead to separation or divorce.

marital separation

marital separation the situation in which a previously cohabiting married couple stops living together and instead maintains individual residences, finances, and so forth. When the couple has children, the term parental separation is often used. Separation may be informal via mutual agreement or legally arranged via an official, enforceable document. In both cases, the partners remain married, which distinguishes separation from divorce. Increasingly common in Western societies, separation has the potential for significant consequences, including diminished psychosocial functioning, deterioration of the parent–child relationship, and long-term emotional disturbances and mental health problems (e.g., anxiety, depression).

marital skew

marital skew an unhealthy pattern in which the pathological behavior of the dominant partner in a couple is accepted by the other partner. See also collusional marriage.

marital subsystem

marital subsystem the relationship between two spouses or partners in a family and their particular interactional rules for cooperation, conflict, and conflict resolution over marital issues (e.g., child rearing).

marital therapy

marital therapy see couples therapy.

mark-and-recapture sampling

mark-and-recapture sampling see capture–tag–recapture sampling.

marker

marker n. 1. a detectable sign, as in a genetic marker or clinical marker. 2. any variation in a process or characteristic that is associated with a condition, event, or other object of interest. For example, enlarged perivascular spaces are a promising neuroimaging marker of small vessel disease. See biochemical marker; biological marker.

market research

market research research undertaken to understand the size and nature of a particular market, together with any significant trends or challenges. This may involve interviews to assess the relative positions of various suppliers in the minds of consumers. For example, a comparison may be made between restaurants that are perceived to offer good service and high-quality food at a low price with those perceived to provide good service and high-quality food at a high price. The term marketing research is used more specifically to mean research into the effectiveness of marketing techniques.

marketing orientation

marketing orientation in the existential psychoanalysis of Erich Fromm, a character pattern in which the individual regards people as commodities and evaluates personal worth in terms of salability. Attributes perceived as leading to business or social success are valued more than knowledge, creativity, integrity, or dedication. According to Fromm, the marketing orientation contributes to shallow relationships and alienation from self and society. Also called marketing character. Compare exploitative orientation; hoarding orientation.

Markov chain

Markov chain a sequence of steps or events in which the probability of each transition depends only on the immediately preceding step and not on any earlier step. For example, when a person considers a behavior change such as losing weight he or she experiences certain stages: The individual could move from not thinking about losing weight (precontemplation) to considering a weight loss plan (contemplation), through to sustaining a reasonable weight (maintenance), and conceivably back to not wanting to think about weight loss. This process could be described as a Markov chain. Also called Markov process. Compare random walk. [Andrei Markov (1856–1922), Russian mathematician]

Marlowe–Crowne Social Desirability Scale (M–C SDS)

Sorry, "marlowe-crowne-social-desirability-scale-m-c-sds" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

Maroteaux–Lamy syndrome

Maroteaux–Lamy syndrome an inherited disorder of connective tissue and skeletal development: one of the mucopolysaccharidoses. It is marked by dwarfism of the trunk and extremities and in some cases delayed closure of the cranial sutures, maldevelopment of the facial bones, and hearing loss. Also called mucopolysaccharidosis VI; systemic mucopolysaccharidosis. [Pierre Maroteaux (1926– ), French geneticist; Maurice Lamy (1895–1975), French physician]

Marplan

Marplan n. a trade name for isocarboxazid.

marriage

marriage n. the social institution in which two (or, less frequently, more) people commit themselves to a socially sanctioned relationship in which sexual intercourse is legitimated and there is legally recognized responsibility for any offspring as well as for each other. Although there are exceptions, the marital partners typically live together in the same residence. See also common-law marriage; domestic partnership; group marriage; same-sex marriage. —marital adj.

marriage counseling

marriage counseling couples counseling with partners who are married. Also called marital counseling.

marriage-enrichment group

marriage-enrichment group a support or therapy group in which married couples meet under the guidance of a professional or nonprofessional leader to discuss marriage-related problems and issues. See also couples therapy.

marsupial

marsupial n. a nonplacental animal of the subclass Metatheria, such as the opossum or Tasmanian devil. Marsupials are born at a very early developmental stage and spend a prolonged period of development in the maternal pouch. Most marsupials are found in the southern hemisphere, particularly in Australia, New Guinea, and nearby islands.

Marxism

Marxism n. a philosophical position and economic theory drawn directly or indirectly from the works of Karl Marx. Although there is much debate about the true nature of Marxism, there is general agreement that it emphasizes the role of economics (control of the means of production) in subtly determining other social institutions, the importance of labor as the foundation of all economies, the failings of capitalism as an economic system, and a utopian vision of social equality. Marxism has spawned, or been appropriated by, a number of social revolutionary and communitarian movements, including communism. See also class theory; dialectical materialism. —Marxist adj., n.

Marxist feminism

Marxist feminism a branch of feminism that locates the oppression of women in the context of a Marxist analysis of the oppression of the working class, thus viewing the oppression as systemic and ubiquitous. Marxist feminism concentrates on the economic aspects of women’s oppression and advocates remedies largely consonant with Marxist principles. See Marxism; radical feminism.

masculinity

masculinity n. possession of social role behaviors that are presumed to be characteristic of a boy or man, as contrasted with maleness, which is genetically determined. —masculine adj.

masculinity–femininity test

masculinity–femininity test any test designed to measure the degree of masculinity or femininity in participants. The earliest was the Terman–Miles Attitude–Interest Analysis Test (1938); others, usually in inventory form, are the Minnesota Multiphasic Personality Inventory, the Guilford–Zimmerman Temperament Survey, and the Gough Femininity Scale. The Bem Sex Role Inventory is one of the few masculinity–femininity tests to include androgyny.

masculinization

masculinization n. see virilism.

masked audiogram

masked audiogram see masking pattern.

masked depression

masked depression a condition in which an individual experiencing a major depressive episode complains of physical symptoms (e.g., headache, backache) rather than mood disturbance, and no biological cause of the physical symptoms can be found.

masking

masking n. 1. in perception, the partial or complete obscuring of one stimulus (the target) by another (the masker). The stimuli may be sounds (see auditory masking), visual images (see visual masking), tastes, odorants, or tactile stimuli. Forward masking occurs when the masker is presented a short time before the target stimulus, backward masking occurs when it is presented shortly afterward, and simultaneous masking occurs when the two stimuli are presented at the same instant. Also called perceptual masking. 2. in statistics, the obscuring of the effect of one variable by the effect of another variable. For example, a researcher interested in whether risky sexual behavior is related to alcohol use might find that an experience of sexual abuse exerts a stronger influence on sexual behavior, thus masking the effect of alcohol use. —mask vb.

masking level difference (MLD)

Sorry, "masking-level-difference-mld" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

masking pattern

masking pattern the detection thresholds as a function of frequency for a pure-tone signal masked by a sound whose spectral characteristics and level are fixed. The y-axis may be either the level of the signal at threshold (in decibels sound-pressure level) or the amount of masking. Also called masked audiogram. See auditory masking.

Maslach Burnout Inventory (MBI)

Sorry, "maslach-burnout-inventory-mbi" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

Maslow’s motivational hierarchy

Maslow’s motivational hierarchy the hierarchy of human motives, or needs, as described by Abraham Maslow, which he developed in part as a reaction against the determinism of the theories of Sigmund Freud and B. F. Skinner. Physiological needs (air, water, food, sleep, sex, etc.) are at the base; followed by safety and security (the safety needs); then love, affection, and gregariousness (the love needs); then prestige, competence, and power (the esteem needs); and, at the highest level, aesthetic needs, the need for knowing, and self-actualization (the metaneeds).

Maslow’s theory of human motivation

Maslow’s theory of human motivation the humanistic view of motivation proposed by Abraham Maslow, in which the higher human needs for understanding, aesthetic values, self-realization, and peak experiences are emphasized. Maslow contrasted the metamotivation arising from such metaneeds with the deficiency motivation arising from physical needs, insecurity, and alienation.

masochism

masochism n. the derivation of pleasure from experiencing pain and humiliation. The term generally denotes sexual masochism but is also applied to experiences not involving sex, such as martyrdom, religious flagellation, or asceticism. In classical psychoanalytic theory, masochism is interpreted as resulting from the death instinct or from aggression turned inward because of excessive guilt feelings. [Leopold Sacher Masoch (1835–1895), Austrian writer] —masochist n. —masochistic adj.

masochistic fantasies

masochistic fantasies fantasies of being whipped, choked, or otherwise hurt or abused as an expression of masochistic tendencies, particularly as a means of achieving sexual excitement. See sexual masochism.

masochistic personality disorder

masochistic personality disorder a personality disorder in which individuals persistently and characteristically obtain gratification or freedom from guilt feelings as a consequence of humiliation, self-derogation, self-sacrifice, wallowing in misery, and, in some instances, submitting to physically sadistic acts. This disorder was listed in DSM–III–R as self-defeating personality disorder but was deleted from DSM–IV–TR. The term is controversial because many believe that in some cases it blames the victim of abuse.

mass action

mass action Karl S. Lashley’s generalization that the size of a cortical lesion, rather than its specific location, determines the extent of any resulting performance decrement. Proposed in 1929 following experimental observations of the effects of different brain lesions on rats’ ability to learn a complex maze, the concept reflects Lashley’s belief that large areas of the cortex function together in learning and other complex processes. This concept is no longer considered completely valid. Also called law of mass action; principle of mass action. See also equipotentiality.

mass contagion

mass contagion a form of social contagion in which behaviors, attitudes, or affect rapidly spread throughout large groups or populations, including those who are widely dispersed across a large area. See also behavioral contagion; emotional contagion.

mass hysteria

mass hysteria see collective hysteria.

mass media

mass media sources of public communication to a wide audience, traditionally including news and entertainment publications (primarily newspapers and magazines) and radio and television broadcasts intended for the general public, but now also including the Internet.

mass murder

mass murder the act of killing several to many people. The mass murder of an entire population (e.g., a racial or ethnic group) is called genocide. See also spree murder.

mass psychology

mass psychology 1. the mental and emotional states and processes that occur in a large body of individuals who, although they may not have any common characteristics, are considered as a whole. 2. the scientific study of these phenomena, including the study of mass movements, collective hysteria, and the effects of the media.

mass reflex

mass reflex 1. an indiscriminate response of many body effectors to a single stimulus, as in “freezing” with fear. 2. a life-threatening condition associated with spinal cord injury in which uncontrolled activation of both autonomic and somatic motor systems occurs.

mass suicide

mass suicide the deliberate ending of the lives of all or most of the members of an intact social group or aggregate by the members themselves, either directly through self-injurious behavior or indirectly by choosing a course of action that will likely be fatal. Examples include extremely hazardous missions undertaken by combat units (see altruistic suicide) and the suicides of the more than 900 members of the People’s Temple in Jonestown, Guyana, in 1978; the 70 members of the Order of the Solar Temple in Europe and Canada between 1994 and 1997; and the 39 Heaven’s Gate followers of Marshall Applewhite in San Diego in 1997. Mass suicide often occurs at the command of a charismatic leader and may be provoked not by despair but by the desire to seek a “higher state of existence” promised by the leader. Also called collective suicide. Compare cluster suicide.

mass-spring model

mass-spring model see equilibrium-point model.

mass-to-specific development

mass-to-specific development in fetal and infantile development, progression from gross, random movements involving the whole body to more refined movements of body parts.

massa intermedia

massa intermedia see interthalamic adhesion.

massage

massage n. the structured stroking or kneading of a body area or of the entire body by hand or by a mechanical or electrical device. Manual massage is usually administered for therapeutic and rehabilitative purposes because the hands can detect abnormalities, such as swellings or muscle spasms. Among the benefits of massage are improved circulation, reduced pain, the promotion of relaxation and healing from injury, and release from tension and psychological stress.

massed practice

massed practice a learning procedure in which practice trials occur close together in time, either in a single lengthy session or in sessions separated by short intervals. Massed practice is often found to be less effective than distributed practice.

massed repetition

massed repetition see repetition effect.

masseter reflex

masseter reflex see jaw jerk.

Masson disk

Masson disk a device for measuring the threshold of brightness vision. The disk is white with a black segmented line along one radius. When it is rotated, varying shades of gray are seen, the darkest at the center. The point at which the disk becomes indistinguishable from the background provides the required measurement. [Antoine-Philibert Masson (1806–1860), French physicist]

MAST

MAST acronym for Michigan Alcoholism Screening Test.

mastery goal

mastery goal see learning goal.

mastery learning

mastery learning 1. the process of gaining knowledge in a certain subject or domain, with the intent of understanding the full scope of that subject area. 2. a theory of education in which students learn material in several different ways over a series of study sessions until they understand the material well enough to teach it to others. 3. the acquisition of material beyond basic recognition, recall, and understanding to a point of thorough cognitive integration at a conceptual level.

mastery orientation

mastery orientation an adaptive pattern of achievement behavior in which individuals enjoy and seek challenge, persist in the face of obstacles, and tend to view their failings as due to lack of effort or poor use of strategy rather than to lack of ability.

mastery play

mastery play play that leads to mastering new skills, such as language and intellectual abilities.

mastery tests

mastery tests assessments used to determine acquisition of the full scope of knowledge in a particular subject area or to evaluate ongoing progress and comprehension.

mastery training

mastery training experimental or real-world training that prepares individuals for aversive situations or conflict by teaching them methods of assertion and constructive control over environmental conditions.

mastoid

mastoid n. a projection from the anterior part of the temporal bone containing air spaces that communicate with the cavity of the middle ear.

masturbation

masturbation n. manipulation of one’s own genital organs, typically the penis or clitoris, for purposes of sexual gratification. The act is usually accompanied by sexual fantasies or erotic literature, pictures, or videos. Masturbation may also include the use of mechanical devices (e.g., a vibrator) or self-stimulation of other organs, such as the anus or nipples. —masturbate vb.

masturbatory reconditioning

masturbatory reconditioning see orgasmic reconditioning.

masturbatory satiation

masturbatory satiation a behavioral treatment aimed at altering the deviant sexual preferences of individuals who commit sex offenses, including rape, pedophilia, and child molestation. The technique has been inappropriately applied to alter homosexual behavior as well. In one version of masturbatory satiation, participants masturbate for prolonged periods of time—continuing even after orgasm—so that the act eventually becomes unsatisfying. In another version, known as verbal satiation, participants voice their deviant sexual fantasies while masturbating past orgasm, continuing until the deviant sexual imagery is no longer arousing. In a third version, participants masturbate to orgasm using appropriate sexual fantasies and afterward continue masturbating to their deviant sexual fantasies in order to pair the pleasurable experience of orgasm with appropriate stimuli and the deviant behavior with excessive, unsatisfying masturbation. All three forms of masturbatory satiation lack a sound empirical basis for effectiveness.

MAT

MAT abbreviation for Miller Analogies Test.

mata elap

mata elap see amok.

matched samples

matched samples two or more sets of study participants that are equivalent to one another with respect to certain relevant variables.

matched-pairs design

matched-pairs design a study involving two groups of participants in which each member of one group is paired with a similar person in the other group, that is, someone who matches them on one or more variables that are not the main focus of the study but nonetheless could influence its outcome. For example, a researcher evaluating the effectiveness of a new drug in treating Alzheimer’s disease might identify pairs of individuals of the same age and intelligence and then randomly assign one person from each pair to the treatment condition that will receive the drug and the other to the control condition that will not. A matched-groups design (matched-samples design; matched-subjects design) is a similar approach but broader in that it allows for the inclusion of more than two groups of participants.

matched-pairs t test

matched-pairs t test a statistical procedure used to test for significant differences between the two sets of data obtained from a matched-pairs design. For example, a researcher could use a matched-pairs t test to assess whether relationship satisfaction significantly differs between two sets of individuals who have been matched for age and gender, where one set has been married for 5 years and the other for 10 years. Also called paired-samples t test.

matching

matching n. a procedure for ensuring that participants in different study conditions are comparable at the beginning of the research on one or more key variables that have the potential to influence results. After multiple sets of matched individuals are created, one member of each set is assigned at random to the experimental group and the other to the control group. For example, a researcher could create two groups whose members are of the same sex and have the same family history of a disease; one group would be given a treatment whereas the other would not. Such an approach would enable the researcher to rule out sex and family history as potential explanations of the study outcome, thereby allowing greater validity to attributing any changes between the groups to the treatment. See also matched-pairs design.

Matching Familiar Figures Test (MFF)

Sorry, "matching-familiar-figures-test-mff" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

matching hypothesis

matching hypothesis the proposition that people tend to form relationships with individuals who have a similar level of social value, often with an emphasis on equality in physical attractiveness. Research indicates that this similarity tends to be greater for couples having a romantic relationship than for friends.

matching law

matching law in operant conditioning, a law that describes the distribution of responses when numerous task options are available. It states that the proportion of responses allocated to an alternative will match the proportion of reinforcement obtained from that alternative. For example, if a pigeon receives two thirds of its food allocation from Alternative A and one third from Alternative B, it will make two thirds of its responses (and give two thirds of its time) to Alternative A. If the pigeon makes fewer than two thirds of its responses to Alternative A—that is, has less sensitivity to reinforcement than the law predicts—then undermatching has occurred. If, however, the pigeon makes more than two thirds—that is, has greater sensitivity to reinforcement than the law predicts—then overmatching has occurred. See also generalized matching law.

matching patients

matching patients the process of prescribing specific interventions or choosing specific therapists for particular patients or diagnostic groups of patients to improve adherence with or effectiveness of treatment. The process is based on the diagnoses, needs, problems, and characteristics of particular patients; on therapist variables, such as race, ethnicity, and experience levels; and on setting variables, such as inpatient or outpatient clinics. Also called psychotherapy matching.

matching to sample

matching to sample a conditional-discrimination procedure that involves both successive discrimination and simultaneous discrimination. Each trial begins with presentation of a sample stimulus. Once the organism responds to that sample, two or more additional stimuli appear, only one of which matches the sample. Reinforcement is contingent on responding to the stimulus that matches. See also arbitrary matching to sample; delayed matching to sample; oddity from sample.

mate guarding

mate guarding a method of preventing a mate from reproducing with others. In nonhuman animals, a male stays close to its mate immediately after copulation and prevents other males from approaching or mating with the female until such time as additional mating will not result in fertilization. In some cases, a copulatory lock literally keeps mates connected for several minutes or hours. See also mate poaching; sperm competition.

mate poaching

mate poaching behavior that is intended to sexually attract someone who is involved in a committed romantic relationship with another partner. In evolutionary theorizing, mate poaching is one of several evolved adaptations, or strategies, for increasing or improving one’s reproductive opportunities. Partners in committed romantic relationships often engage in mate guarding to thwart the possibility of mate poaching. Research shows that mate-poaching attempts are commonplace in most cultures in the world. Among nonhuman animals, sneak mating is a somewhat similar behavior in some males.

mate selection

mate selection the choice of an appropriate partner for reproduction. In species where female parental investment is high, females are thought to be more careful in their choice of mates than males. However, in species where parental contribution to survival of offspring is more nearly equal, mate selection is shown by both sexes. Mate selection may be based on (a) behavioral traits, such as the ability to defend a territory or to be dominant over others; (b) exaggerated signals of quality, such as bright tail plumage in the peacock; or (c) evaluations made during courtship. In species where females are smaller than males, females may mate with several males, either selectively keeping the sperm of only one or two or mating with the most dominant male at the time closest to possible conception (see cryptic female choice; sexual aggression). See also sexual selection. Compare random mating.

mate swapping

mate swapping see partner swapping.

mate value

mate value an overall assessment of a person’s desirability as a romantic or reproductive partner. Many factors contribute to a person’s mate value, such as youthfulness, physical attractiveness, status, and wealth. The higher a person’s mate value, the more selective he or she can be when choosing a partner. The concept of mate value was proposed by evolutionary theorists on the basis of ethological research with nonhuman animals, although it is now used by researchers with diverse approaches. Research has demonstrated that people generally form committed relationships with others who have roughly similar levels of mate value.

material cause

material cause see cause.

material feminism

material feminism a movement in 19th-century and early 20th-century feminism that concentrated on improving the material conditions of women’s lives. Campaigners in this tradition sought to end women’s legal, educational, and employment disabilities and to ease the burden of their domestic duties.

material self

material self see empirical self.

materialism

materialism n. 1. the philosophical position that everything, including mental events, is composed of physical matter and is thus subject to the laws of physics. From this perspective, the mind is considered to exist solely as a set of brain processes (see mind–body problem). Such philosophies can be traced back to ancient times but gained a new impetus from advances in the physical sciences beginning in the 17th century. A particular form of materialism is the dialectical materialism of classical Marxism. 2. the position that the causes of behavior are to be found in the material of the body, particularly the nervous system. It is nearly always associated with hard determinism. See also identity theory; physicalism. Compare idealism; immaterialism. 3. a value system that emphasizes the pursuit and acquisition of material goods and luxuries, typically perceived by the individual as a measure of personal worth and achievement, often at the expense of moral, psychological, and social considerations. —materialist adj., n. —materialistic adj.

materialization

materialization n. in spiritualism, the alleged production of a spirit in bodily form during a seance or of some other physical object by apparently supernatural means (see apport). See also ectoplasm. —materialize vb.

maternal aggression

maternal aggression a form of aggression in nonhuman animals in which females defend their offspring against potential threats from intruders by means of threat displays or attack behavior.

maternal attitudes

maternal attitudes attitudes of the mother toward her children, particularly those attitudes that play an important role in her children’s health, character formation, emotional adjustment, and self-image, as well as in her own self-perception as a mother.

maternal behavior

maternal behavior the actions of females associated with caring for their young. These can range from feeding or nursing to protection, thermoregulation, and teaching skills to the young. Its exact expression, however, depends on a number of factors, including the developmental status of the young at birth, levels of various hormones (e.g., estrogen, oxytocin, progesterone, prolactin), and environmental influences. The analogous male behavior is known as paternal behavior. See also parental behavior.

maternal brain

maternal brain in the mammalian female nervous system, the expression of inherent neuroplasticity that is associated with and necessary for reproduction and in which multilevel changes to neurons and neuronal activity occur that enhance a mother’s cognition and behavior toward her young during the pre- and postnatal period.

maternal deprivation

maternal deprivation lack of adequate nurturing for a young animal or child due to the absence or premature loss of, or neglect by, its mother or primary caregiver, postulated to affect an individual’s early behavioral, physical, social, and emotional development negatively. See also failure to thrive; marasmus.

maternal drive

maternal drive the motivation of female animals to care for offspring.

maternal environment

maternal environment conditions in the uterus of a pregnant woman that affect fetal development and are hypothesized to have long-term postnatal effects on the health of the child. See fetal programming.

maternal memory

maternal memory the long-term retention of memory for maternal behavior. Once a female animal has experienced a pregnancy and interaction with her offspring, she retains the memory of the requisite behaviors for their care. For example, a female rat that has already had pups will be quicker to display maternal behavior when placed with foster pups than will a female rat that has not experienced pregnancy and pup-rearing. See also maternal brain.

maternal PKU

maternal PKU a condition in women who have phenylketonuria (PKU) and become pregnant. Expectant mothers with high levels of blood phenylalanine—hyperphenylalaninemia—are at risk of giving birth to offspring with high rates of congenital heart defects, intrauterine growth retardation, intellectual disability, and microcephaly (a small head). Treatment entails dietary management for the expectant mother before and during pregnancy to reduce blood levels of phenylalanine.

maternal reverie

maternal reverie a mother’s capacity to understand what her infant is feeling and to ameliorate the infant’s anxiety and distress. See also attunement; primary maternal preoccupation. [first described in 1962 by British psychoanalyst Wilfred Bion (1897–1979)]

maternity blues

maternity blues see baby blues.

mathematical ability

mathematical ability the ability used to solve various kinds of quantitative problems, such as mathematical word problems, computational problems, and number-concept problems. It comprises a number of distinct skills.

mathematical biology

mathematical biology a branch of biology that deals with the development of mathematical models of biological phenomena, such as conditioning and nerve conduction.

mathematical learning theory

mathematical learning theory any of a variety of theories that use quantitative terms to characterize the learning of individuals or groups or the results of learning trials. An important example is the stimulus sampling theory.

mathematical model

mathematical model the representation of a psychological or physiological function, or other process, in mathematical terms, such as formulas or equations (e.g., Fechner’s law).

mathematical psychology

mathematical psychology an approach to psychological phenomena that uses mathematical techniques to model the underlying processes and to predict the outcomes of these processes. Closely related to psychometrics and statistics, it is used across several major subdisciplines, especially cognitive psychology, psychophysics, and perception.

mathematical statistics

mathematical statistics see theoretical statistics.

mathematico-deductive method

mathematico-deductive method 1. the use of postulates and corollaries in mathematical form to develop a system or theory. 2. see hypothetico-deductive method.

mathematics anxiety

mathematics anxiety apprehensiveness and tension associated with the performance of arithmetic and other mathematical tasks. Often thought to be related to test anxiety, mathematics anxiety has been proposed as an important factor undermining the development of mathematical skills: It frequently causes distress, disrupts the use of working memory for maintaining task focus, negatively affects achievement scores, and potentially results in dislike and avoidance of all math-related tasks. It is seen in students of all ages, regardless of their actual math abilities, and is considered more prevalent in females than males. A number of factors are related to the phenomenon, including low self-esteem and self-efficacy, lack of confidence, trait anxiety, perfectionism, and previous negative experiences with the subject material. Teacher-based instruction that encourages students as they work through a math problem, teaches them effective skills in solving such problems, and demonstrates that positive attitudes toward mathematics can reduce this type of anxiety. Cooperative learning, computer-assisted instruction, and the use of mathematical games to make the learning process more relaxed are also effective.

mathematics disorder

mathematics disorder in DSM–IV–TR, a learning disorder in which mathematical ability is substantially below what is expected given the person’s chronological age, education, and measured intelligence. It may involve (among other problems) difficulties in counting, learning multiplication tables, understanding mathematical problems and performing mathematical operations, reading numerical symbols, and copying numbers. In DSM–5, the disorder has been subsumed within a category labeled specific learning disorder and is no longer considered a distinct entity.

mating behavior

mating behavior the activities that are involved in reproduction, including courtship, mate selection, and copulation. Mating behavior varies with the species and may have several functions in addition to successful conception: preparing both mates physiologically, providing cues for mate selection, and coordinating behavior of mates for nest building and subsequent care of young.

mating system

mating system the organization of typical mating patterns within a species. Mating systems include monogamy, in which two individuals mate exclusively with each other; polygyny, in which a male mates with multiple females; polyandry, in which a female mates with multiple males; and polygynandry, in which both sexes mate with multiple partners.

matriarchy

matriarchy n. 1. a society in which descent and inheritance is matrilineal, that is, traced through the female only. See unilateral descent. See also descent group. 2. more loosely, a family, group, or society in which women are dominant. Compare patriarchy. —matriarchal adj.

matricide

matricide n. 1. the killing of one’s own mother. 2. a person who kills his or her own mother. Compare patricide. —matricidal adj.

matrifocal

matrifocal adj. describing a family centered on the mother or a culture in which the role of the mother is central.

matrilineal

matrilineal adj. see matriarchy.

matrilocal

matrilocal adj. denoting a living arrangement in which a married couple resides with or in proximity to the wife’s mother or relatives, or a culture in which this is the norm. Also called uxorilocal. Compare neolocal; patrilocal.

matrix

matrix n. 1. a context or environment within which something else is enclosed, embedded, originates, or develops. 2. a rectangular ordered arrangement (array) of numbers in rows and columns. Individual items in a matrix are called elements or entries. Many different types of matrices are used in statistics, such as the correlation matrix and the covariance matrix.

matrix algebra

matrix algebra a set of mathematical rules for analyzing large numbers of variables arranged in matrices. Matrix algebra procedures may involve basic calculations, such as adding and subtracting matrices, and also more complex processes, such as multiplying and dividing matrices.

matrix organization

matrix organization a complex type of organizational structure in which employees are grouped not only by the function they perform (e.g., marketing, production, research and development, engineering) but also by the product or project on which they are working. Employees working within a matrix organization report to both a functional boss and a product or project boss. Compare unity of command.

Matthew effect

Matthew effect 1. a phenomenon in the sociology of science whereby established researchers receive more credit for a discovery than less well known researchers who may have made an equal or greater contribution. [first described by U.S. sociologist Robert K. Merton (1910–2003) and named for a verse in the Gospel according to St. Matthew: “For to everyone who has will be given, and he will have abundance, but from him who doesn’t have, even that which he has will be taken away” (25:29)] 2. in child development, the tendency for the difference between high and low performers (e.g., good and poor readers) to increase over time. Also called accumulated advantage. [described by Canadian psychologist Keith E. Stanovich]

maturation

maturation n. 1. the biological processes involved in an organism’s becoming functional or fully developed. 2. naturally occurring time-related changes in a participant (e.g., growth, aging, fatigue, boredom, attention shifts) that pose a threat to the internal validity of a study, particularly a longitudinal one. These processes—as opposed to the specific treatment or intervention—may explain any changes in participants during the experiment. For example, a researcher may study substance use in a set of individuals from early adolescence to late adulthood. In the study, substance use may naturally decline as a function of the development of the participants rather than because of the influence of an experimental intervention. Thus, the investigator would want to assess and possibly control for this maturation effect in order to maintain the internal validity of the study.

maturation hypothesis

maturation hypothesis a generalization that some behaviors and processes, such as language acquisition, are innate but do not appear until appropriate organs and neural systems have matured.

maturational crisis

maturational crisis a life-changing event, such as marriage or retirement, that often is encountered during the typical course of development and that requires significant psychological, behavioral, or other adjustments. Also called developmental crisis; normative crisis.

maturational lag

maturational lag slowness or delay in some aspects of neurological development that may affect cognition, perception, and behavior.

maturity

maturity n. a state of completed growth or development, as in adulthood. See developmental levels.

Maximally Discriminative Facial Movement Coding System (MAX)

Sorry, "maximally-discriminative-facial-movement-coding-system-max" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

maximin strategy

maximin strategy in game theory or decision making, a tactic in which an individual chooses the best of a set of worst possible outcomes or payoffs. For example, participants in a study may need to choose whichever outcome would best maximize a minimum advantage: withdrawing from a scenario in which they are currently performing poorly, or continuing and possibly doing even worse. Compare minimax strategy.

maximizer

maximizer n. a type of consumer who wishes to make the very best decision. For example, a maximizer on a shopping trip in a grocery store is likely to carefully examine every single cereal before buying one. Generally, maximizers are considered more susceptible than the converse satisficers to all forms of regret leading to buyer’s remorse. [coined in 2002 by U.S. psychologist Barry Schwartz (1946– )]

maximum likelihood

maximum likelihood a statistical technique in which the set of possible values for the parameters of a distribution is estimated based on the most probable sample of observations that one might have obtained from that population. The values derived from this procedure are referred to as maximum likelihood parameter estimates or maximum likelihood estimates and can be used to obtain an overall estimate of how well a given model fits the data. Maximum likelihood techniques are used in several statistical methods, such as logistic regression, hierarchical linear modeling, and structural equation modeling. Also called maximum likelihood estimation (MLE).

maximum-security unit

maximum-security unit a section of a mental institution reserved for patients who are likely to harm themselves or others.

Maxwell disks

Maxwell disks a series of slotted color disks on a rotating spindle, used as a color mixer. [James Clerk Maxwell (1831–1879), British physicist]

Maxwellian view

Maxwellian view an optical arrangement that causes a visual stimulus to be confined to the center of the pupil. The alternative, a Newtonian view, allows light to pass through all parts of the pupil. [James Clerk Maxwell]

maze

maze n. a system of intersecting paths and blind alleys that must be navigated from an entrance to an exit. Various types of mazes are used in experiments with both human and nonhuman animals. They are often used, for example, in studies of animal cognition that investigate spatial learning and memory (see Morris water maze; radial maze), organization of cognitive maps, and the foraging strategies of predators searching for prey. A common human maze is a printed paper pattern on which the participant traces the correct pathway with a pencil; an example is the Porteus Maze Test, which tests planning and problem-solving ability. See also alley maze; elevated maze; T maze; Y maze.

maze learning

maze learning learning to reach the goal object or objects in a maze by starting from a designated point and following various paths, some of which do not lead to the goal. The maze-learning process usually involves multiple trials and is regarded as successful when the participant can reach the goal in the most direct way with minimal errors.

maze task

maze task a measure of visual planning in which participants must trace a route through a series of progressively more complex mazes without entering blind alleys. An example of this type of test is the Porteus Maze Test.

maze-bright and maze-dull rats

maze-bright and maze-dull rats two groups of rats that were separated based on their performance in a standardized maze problem. Those that performed best were bred with each other, as were those that performed most poorly. Over relatively few generations, there was a complete separation in performance, with none of the maze-bright rats overlapping in scores with maze-dull rats. However, the selective breeding appeared to be specific to the maze tests that were used and did not affect learning ability more generally; moreover, maze-dull rats reared in an enriched environment (see enrichment) could perform as well as maze-bright rats.

MBD

MBD abbreviation for minimal brain dysfunction.

MBE

MBE abbreviation for mind–brain–education. See neuroeducation.

MBHO

MBHO abbreviation for managed behavioral health organization.

MBI

MBI abbreviation for Maslach Burnout Inventory.

MBO

MBO abbreviation for management by objectives.

MBT

MBT abbreviation for mentalization-based treatment. See mentalization.

MBTI

MBTI abbreviation for Myers–Briggs Type Indicator.

MC4-R

MC4-R abbreviation for melanocortin-4 receptor.

MCA

MCA abbreviation for multiple classification analysis. See multiple discriminant analysis.

McCarthy Scales of Children’s Abilities

McCarthy Scales of Children’s Abilities a comprehensive instrument used to measure the cognitive and motor abilities of children between 2½ and 8½ years of age, comprising 18 subtests on 6 overlapping scales: Verbal, Perceptual-Performance, Quantitative, General Cognitive, Memory, and Motor. [developed in 1972 by Dorothea McCarthy (1906–1974), U.S. developmental psychologist]

McCarthy Screening Test (MST)

Sorry, "mccarthy-screening-test-mst" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

McCollough effect

McCollough effect see contingent aftereffect. [Celeste McCollough (1926– ), U.S. psychologist]

MCE

MCE abbreviation for medical care evaluation.

MCI

MCI abbreviation for mild cognitive impairment.

MCL

MCL abbreviation for most comfortable loudness.

MCM

MCM abbreviation for metacognitive model of attitudes.

MCMI

MCMI abbreviation for Millon Clinical Multiaxial Inventory.

McNaughton rule (McNaghten rule; McNaughten rule)

Sorry, "mcnaughton-rule-mcnaghten-rule-mcnaughten-rule" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

MCO

MCO abbreviation for managed care organization. See managed care.

MCS

MCS abbreviation for minimally conscious state.

MD

MD abbreviation for muscular dystrophy.

MDA

MDA n. 1. 3,4-methylenedioxyamphetamine: a synthetic hallucinogen of the phenylisopropylamine family (see phenylethylamine). Because at low doses it acts as a CNS stimulant and euphoriant, MDA was once proposed as an aid to psychotherapy, but this use has not been supported. It is thought that MDA’s psychostimulant properties occur through enhanced neurotransmission of norepinephrine and its hallucinogenic action through augmentation of serotonin transmission. MDA is a metabolite of MDMA and may be responsible for much of MDMA’s action; there is some concern that these drugs and other synthetic amphetamine derivatives cause neuronal degeneration. 2. abbreviation for multiple discriminant analysis.

MDMA

MDMA n. 3,4-methylenedioxymethamphetamine: a substituted phenylethylamine that, like its analog MDA, is a catecholamine-like hallucinogen with amphetamine-like stimulant properties that may produce visual disturbances and hallucinations at high doses. It is among the most commonly used illicit drugs, generally sold under the name Ecstasy. Taken orally, onset of effects is rapid; the high lasts several hours, and residual effects can be experienced for several days. Intoxication is characterized by euphoria, feelings of closeness and spirituality, and diverse symptoms of autonomic arousal. Widespread illicit use of MDMA as a club drug has caused increasing concern as nerve damage and serotonin dysfunction have been established as resulting from prolonged use. Persistent memory dysfunction and impaired decision making and self-control as well as depressed mood have been well documented. When used during periods of intense activity (as often occurs during rave parties), it may be toxic or fatal. It may, however, have some beneficial clinical use and is being studied as a possible treatment for posttraumatic stress disorder.

MDS

MDS abbreviation for multidimensional scaling.

me

me pron. the objective pronoun referring to the self. In William James’s psychology, the “me” is the empirical self.

mean

mean n. the numerical average of a set of scores, computed as the sum of all scores divided by the number of scores. For example, suppose a health researcher sampled five individuals and found their numbers of hours of exercise per week to be 3, 1, 5, 4, and 7, respectively. The mean number of exercise hours per week thus would be (3 + 1 + 5 + 4 + 7)/5 = 20/5 = 4. The mean is the most widely used statistic for describing central tendency. Also called arithmetic mean; arithmetic average. See also geometric mean; harmonic mean.

mean deviation

mean deviation for a set of numbers, a measure of dispersion or spread equal to the average of the differences between each number and the mean value. It is given by (Σ|xi – μ|)/n, where μ is the mean value and n the number of values.

mean difference

mean difference a measure of variability in a data set calculated as the average of the distances between each score and each of the other scores, disregarding whether the deviation is positive or negative. For example, consider the following three scores: 1, 3, and 9. The mean difference would be calculated as (|1−3| + |1−9| + |3−1| + |3−9| + |9−1| + |9−3|)/6 = (2 + 8 + 2 + 6 + 8 + 6)/6 = 32/6 = 5.33.

mean effect size

mean effect size in a meta-analysis, a measure of the average effect size across multiple studies. For example, an investigator analyzing several studies assessing a new treatment may determine a mean effect size by calculating the average standardized difference between treatment and control groups over all of the studies. Calculations of mean effect size often take variance and reliability into account by assigning different weights to the values derived from different studies. A study with a large sample, for instance, or one that uses more precise measurement techniques may be weighted to have a greater impact in determining the mean effect size.

mean length of utterance (MLU)

Sorry, "mean-length-of-utterance-mlu" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mean square

mean square (symbol: MS) an estimator of variance calculated as a sum of squares divided by its degrees of freedom. It is used primarily in the analysis of variance, in which an F ratio is obtained by dividing the mean square between groups by the mean square within groups. The mean square also is used to determine the accuracy of regression analysis models, indicating the amount of variance explained by a model (MSregression) compared to the amount of error or unexplained variance (MSresidual).

mean square error

mean square error (symbol: MSE) the average amount of error variance within a data set, given as the typical squared distance of a score from the mean score for the set. Mean square error may be calculated in both analysis of variance and regression analysis. In the former it is referred to more specifically as the within-groups mean square and used as the denominator when calculating an F ratio; in the latter it is known as a residual mean square (or mean square residual) and gives the mean difference between actual scores and those predicted by a regression model. A large mean square error indicates that scores are not homogeneous within groups or are not consistent with prediction, such that there is more “noise” than “signal.” For example, a large mean square error in gender research would show no significant differences between groups of males and groups of females.

mean square residual

mean square residual (symbol: MSR) see mean square error.

mean-gradation method

mean-gradation method see method of equal-appearing intervals.

meaning

meaning n. the cognitive or emotional significance of a word or sequence of words, or of a concept, sign, or symbolic act. This may include a range of implied or associated ideas (connotative meaning) as well as a literal significance (denotative meaning). The study of meaning in language is semantics, and that of meaning in symbolic systems generally is semiotics. —mean vb. —meaningful adj.

meaning-centered therapy

meaning-centered therapy see logotherapy.

meaningful learning

meaningful learning learning new material or information by relating it to the learner’s experience or existing knowledge base, as contrasted with the rote learning of material that has less relevance. See also readiness.

meaninglessness

meaninglessness n. a pervasive sense of the absence of significance, direction, or purpose. A sense of meaninglessness regarding one’s life or life in general is sometimes a focal issue in psychotherapy. The perception of meaninglessness poses the central problem that the existential approach attempts to solve or accommodate. See also existential psychotherapy; logotherapy; will to meaning.

means object

means object in purposive behaviorism, any object, response, event, or condition that contributes to an organism’s progress toward a goal. Also called means situation.

means–ends analysis

means–ends analysis 1. in artificial intelligence, a technique to solve problems that sets up subgoals as means to achieve the goals (ends) and compares subgoals and goals using a recursive goal-reduction search procedure. See General Problem Solver. 2. more generally, any problem-solving strategy that assesses the difference between the current state and a desired end state and attempts to discover means to reduce that difference. Such a strategy would not discard means to the end that appear to be “blocked,” but it would consider possible ways to overcome any such intermediate problem.

measure

measure n. an item or set of items that provides an indication of the quantity or nature of the phenomenon under study. It is sometimes necessary in research to have more than one measure for each of the main variables of interest.

measure of association

measure of association any of various indices of the degree to which two or more variables are related. One of the most common measures of association is the correlation coefficient.

measurement

measurement n. the act of appraising the extent of some amount, dimension, or criterion—or the resultant descriptive or quantified appraisal itself. A measurement is often, but not always, expressed as a numerical value.

measurement error

measurement error in classical test theory, any difference between an observed score and the true score. Measurement error may arise from flaws in the assessment instrument, mistakes in using the instrument, or random or chance factors. For example, an investigator may obtain biased results from a survey because of problems with question wording or response options, question order, variability in administration, and so forth.

measurement invariance

measurement invariance the situation in which a scale or construct provides the same results across several different samples or populations. For example, an intelligence test could be said to have measurement invariance if it yields similar results for individuals of varying gender, ethnicity, or age. Measurement invariance may apply to a single relevant characteristic (e.g., gender only), several characteristics (e.g., gender and ethnicity), or all possible characteristics and situations. Compare selection invariance.

measurement level

measurement level the degree of specificity, accuracy, and precision in a particular set of observations or scores, as reflected in the measurement scale used.

measurement model

measurement model in structural equation modeling, a model that quantifies the association between observations obtained during research (indicators) and theoretical underlying constructs or factors. When carrying out a confirmatory factor analysis, for example, one assesses a hypothesized measurement model that specifies the relationships between observed indicators and the latent variables that support or affect them.

measurement scale

measurement scale any of four common methods for quantifying attributes of variables during the course of research, listed in order of increasing power and complexity: nominal scale, ordinal scale, interval scale, and ratio scale. More specifically, nominal scales consist of named categories with no numerical meaning (e.g., gender, birthplace), ordinal scales comprise rankings from highest to lowest or vice versa (e.g., birth order, contest winners), interval scales provide equal distance between numerical values but have an arbitrary zero point (e.g., degrees Fahrenheit, checkbook balance), and ratio scales provide equal distance between numerical values with an exact zero point (e.g., height, weight).

measurement theory

measurement theory a field of study that examines the attribution of values to traits, characteristics, or constructs. Measurement theory focuses on assessing the true score of an attribute, such that an obtained value has a close correspondence with the actual quantity, with high reliability and little measurement error. See also classical test theory.

measures of intelligence

measures of intelligence a series of norm-referenced tests used to determine an individual’s ability to learn, reason, understand concepts, and acquire knowledge. See EEG measures of intelligence; ERP measures of intelligence; fMRI measures of intelligence. See also assessment of intelligence.

mecamylamine

mecamylamine n. a ganglionic blocking agent formerly widely used in the treatment of hypertension. Because of the severity of its side effects, which include tremor, sedation, and movement disorders, this use is now rare. However, because mecamylamine has preferential antagonistic action at nicotinic receptors, it has been investigated as a possible antismoking agent. It has also been used in the treatment of Tourette’s disorder and is being studied as an augmenting agent to SSRIs for the treatment of depression. U.S. trade name: Inversine.

mechanical aptitude

mechanical aptitude an ability to comprehend and deal with machines or mechanisms and the principles underlying their construction and function.

mechanical causality

mechanical causality a construct that explains the causes of things and events, including behaviors, in terms of the causal relations among the parts of a machine. Such an explanation will nearly always be one of linear causation. Mechanical causality is a type of hard determinism. See mechanistic theory.

mechanical intelligence

mechanical intelligence the ability to understand and manage concrete objects.

mechanical-aptitude test

mechanical-aptitude test any of various tests designed to measure abilities related to mechanical work, such as mechanical knowledge, spatial relations, perceptual skills, understanding of mechanical principles, mechanical assembly, and manual dexterity.

mechanical-comprehension test

mechanical-comprehension test 1. an assessment that measures an individual’s aptitude to learn mechanical skills. It requires a grasp of the principles underlying the operation and repair of complex devices. 2. an assessment used to determine understanding of concepts relating to machinery or tools.

mechanical-man concept

mechanical-man concept the idea that human beings can be understood as living machines subject only to physical processes and not subject to nonphysical phenomena, such as consciousness. This is often cited as a model for the image of human beings proposed by behaviorism and similar deterministic and naturalistic theories. See also mechanical causality; mechanistic theory.

mechanism

mechanism n. 1. in general, a device or physical property by which something is accomplished, or an explanation that relies on such a device or property. 2. a philosophical position, similar to that of materialism, that provides explanations in terms of underlying physical properties. See mechanical causality; mechanistic theory. 3. the concept of the human being as a machine. See mechanical-man concept. [credited to Julien Offray de La Mettrie] 4. in psychodynamics, see mental mechanism.

mechanistic interactionism

mechanistic interactionism a theory that considers both individual (dispositional) and situational variables in the determination of behavior. The relative weight assigned to dispositional and situational factors may be affected by certain moderating variables, including the nature of a situation: A highly structured situation may influence behavior more than will dispositional factors, and a highly ambiguous situation may allow dispositional factors to play a larger role in determining behavior.

mechanistic theory

mechanistic theory the assumption that psychological processes and behaviors ultimately can be understood in the same way that mechanical or physiological processes are understood. Its explanations of human behavior are based on the model or metaphor of a machine and invoke mechanical causality, reducing complex psychological phenomena to simpler physical phenomena. Also called mechanistic approach. See reductionism.

mechanoreceptor

mechanoreceptor n. a receptor that is sensitive to mechanical forms of stimuli. Examples of mechanoreceptors are the receptors in the ear that translate sound waves into nerve impulses, the touch receptors in the skin, and the receptors in the joints and muscles (see proprioceptor).

Meckel’s syndrome

Meckel’s syndrome a congenital disorder marked by microcephaly; eye, ear, and olfactory abnormalities; and varying degrees of brain-tissue anomalies. Some affected children show premature closure of skull sutures. The patients either are stillborn or die in early infancy. [Johann Friedrich Meckel (1781–1833), German anatomist]

Medea complex

Medea complex a mother’s wish to kill her children as a means of revenge against the father. The term is derived from Greek mythology, in which Medea killed her children fathered by Jason after he deserted her for a younger woman. See also filicide.

media psychology

media psychology a subspecialty in psychology that studies the influence of television, film, radio, the Internet, social media, advertising, mobile communications, and various other media on people’s thoughts, perceptions, emotions, beliefs, behaviors, and relationships.

media richness

media richness the relative intensity and complexity of a communication channel. Face-to-face communication is a good example of a rich medium, as it involves a complex interaction of verbal and nonverbal cues; by contrast, communication exclusively via written messages is a lean medium. [proposed in 1984 by U.S. organizational and management theorists Richard L. Daft and Robert H. Lengel]

medial

medial adj. toward or at the middle of the body or of an organ. Compare lateral. —medially adv.

medial amygdala

medial amygdala a portion of the amygdala that receives olfactory and pheromonal information and participates in fear responses.

medial bundle

medial bundle a group of sensory fibers located in the middle portion of a body structure. For example, there is a medial bundle in the knee.

medial forebrain bundle

medial forebrain bundle a collection of nerve fibers passing through the midline of the forebrain to the hypothalamus. It includes tracts originating in the locus ceruleus, substantia nigra, and ventral tegmental area and provides the chief pathway for reciprocal connections between the hypothalamus and the biogenic amine systems of the brainstem.

medial geniculate nucleus

medial geniculate nucleus either of a pair of nuclei in the thalamus, toward the middle of the lateral geniculate nucleus, that receive, process, and relay auditory information. Each receives input from the inferior colliculus and sends output to the auditory cortex. Also called medial geniculate body.

medial lemniscus

medial lemniscus either of a pair of somatosensory tracts in the midbrain carrying fibers from the spinal cord that communicate with the thalamus. They form part of the lemniscal system.

medial prefrontal cortex

medial prefrontal cortex the midline region of the prefrontal cortex, roughly the frontal third of the two inner walls of the cortical hemispheres. This region plays a prominent role in executive functions, conflict resolution, and mood regulation.

medial preoptic area (mPOA)

Sorry, "medial-preoptic-area-mpoa" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

medial rectus

medial rectus an extrinsic eye muscle that rotates the eye medially (i.e., toward the midline).

medial temporal amnesia

medial temporal amnesia anterograde and retrograde amnesia caused by damage to the medial temporal lobe. Causes include infarction of the posterior cerebral artery, anoxia, encephalitis, temporal lobectomy, and trauma. See amnestic disorder.

medial temporal gyrus (median temporal gyrus)

Sorry, "medial-temporal-gyrus-median-temporal-gyrus" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

medial temporal lobe

medial temporal lobe the region toward the middle of the temporal lobe of each cerebral hemisphere. It contains the pyriform area, the amygdala, and the hippocampus. It is involved particularly in learning and memory.

medial temporal lobe epilepsy

medial temporal lobe epilepsy see limbic epilepsy.

median

median n. the midpoint in a distribution, that is, the score or value that divides it into two equal-sized halves. The median is a measure of central tendency that is particularly useful when analyzing data that have skewness (i.e., lopsidedness), because it is more resistant to the influence of extreme values.

median effective dose

median effective dose see effective dose.

median lethal dose

median lethal dose see lethal dose.

median nerve

median nerve a nerve that supplies sensory and motor fibers to the arm and hand. Its fibers run through the brachial plexus.

median test

median test a nonparametric method that assesses the equality of the midpoints (medians) in two or more samples of data to determine whether they come from the same population. Although previously used to indicate any of several alternative procedures, the term generally is used now to refer to the Wilcoxon–Mann–Whitney test.

median-cleft-face syndrome

median-cleft-face syndrome see frontonasal dysplasia.

mediate experience

mediate experience conscious awareness and interpretation of external events and stimuli. Mediate experience provides meaning and additional information not contained in the event or stimulus itself. It is contrasted with immediate experience, the elements or characteristics of the event or stimuli as perceived directly and without interpretation. Introspection makes use of immediate experience in analyzing the contents of mediate experience. [defined by Wilhelm Wundt]

mediated generalization

mediated generalization a type of stimulus generalization in which a conditioned response is elicited by a new stimulus that is notably different from, but in some way associated with, the original conditioned stimulus. For example, a person conditioned to feel anxious on hearing a bell may also become anxious on hearing the word bell. See stimulus equivalence.

mediated response

mediated response a response that is elicited by a stimulus and is subsequently responsible for the initiation of a behavior.

mediating behavior

mediating behavior behavior that improves either the rate or the probability of reinforcement of a target behavior for which reinforcement is arranged. Compare adjunctive behavior; collateral behavior; interim behavior.

mediation

mediation n. in dispute resolution, use of a neutral outside person—the mediator—to help the contending parties communicate and reach a compromise. The process of mediation has gained popularity, particularly for couples involved in separation or divorce proceedings (see divorce mediation).

mediation process

mediation process any of the cognitive processes that are presumed to occur in the mind between reception of a stimulus and initiation of a response. These may include interpretation of sense data, retrieval of stored information, judgments and evaluations, computations, reasoning, and other mental operations.

mediation theory

mediation theory the hypothesis that stimuli affect behavior indirectly through an intervening process, as opposed to a simpler stimulus–response model. For example, cognitive therapists maintain that the effect an external event has on an individual is influenced by the individual’s thoughts and perceptions of that event.

mediational deficiency

mediational deficiency in problem solving, a person’s inability to make use of a particular strategy to benefit task performance even if it has been taught to him or her. Compare production deficiency; utilization deficiency.

mediational learning

mediational learning a form of learning that involves the use of mediators to bridge the association between two or more events that are not directly contiguous in space or time. The mediators are events or processes that serve as cues.

mediator

mediator n. 1. an unseen process, event, or system that exists between a stimulus and a response, between the source and destination of a neural impulse, or between the transmitter and receiver of communications. 2. a person—for example, a lawyer or psychologist—who helps contending parties communicate and reach a compromise. See also divorce mediation. 3. in statistical analyses, an intermediary or intervening variable that accounts for an observed relation between two other variables. For example, a researcher may posit a model involving an independent variable of ability, a mediator of self-efficacy, and a dependent variable of achievement. Thus, ability is hypothesized to influence self-efficacy, which in turn is thought to influence achievement.

Medicaid

Medicaid n. a joint federal and state program, instituted by law in 1965 (Title XIX of the Social Security Act), that provides medical benefits for people with low income and limited resources. Medicaid programs follow broad federal guidelines, but each state determines specific benefits and amounts of payments.

Medicaid Waiver

Medicaid Waiver see home and community-based services.

medical anthropology

medical anthropology a subdiscipline in cultural anthropology that applies anthropological theory and research methodology to the study of topics relating to health, health care, disease, and other medical areas.

medical audit

medical audit a systematic evaluation of the effectiveness of diagnostic and treatment procedures. A retrospective medical audit is based on a review of a patient’s charts after he or she has been discharged; a concurrent medical audit is conducted while the patient is still under treatment.

medical care evaluation (MCE)

Sorry, "medical-care-evaluation-mce" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

medical family therapy

medical family therapy a form of psychotherapy that combines a biopsychosocial systems approach with family systems theory to help families deal with the health problems of a family member. This therapy emphasizes collaboration with others—physicians, nurses, occupational therapists, nutritionists, and the like—in the individual family member’s health care team.

medical food

medical food a product specifically developed to meet the nutritional needs of a person who cannot eat or digest ordinary foods or who has a condition that precludes receiving sufficient nutrition from ordinary foods. Medical foods are taken under medical supervision.

medical history

medical history the portion of the developmental history, or anamnesis, that focuses on the patient’s health throughout life, including congenital or acquired illnesses and disorders. The object is to uncover, where possible, clues to the cause of the patient’s current condition.

medical home

medical home see health home.

medical model

medical model 1. the concept that mental and emotional problems are analogous to biological problems—that is, they have detectable, specific, physiological causes (e.g., an abnormal gene or damaged cell) and are amenable to cure or improvement by specific treatment. 2. in evaluation research, a systems-analysis approach to evaluation that considers the interrelatedness of all the factors that may affect performance and monitors possible side effects of treatment. Compare engineering model.

medical psychology

medical psychology 1. an area of applied psychology devoted to psychological questions arising in the practice of medicine, including emotional reactions to illness, treatment adherence, attitudes toward terminal illness and impending death, psychological means of relieving pain (e.g., hypnotic suggestion), and reactions to disability. See also health psychology. 2. see prescribing psychology.

medical psychotherapy

medical psychotherapy psychotherapy that makes use of medication and other medical techniques in the treatment of mental illness.

medical rehabilitation

medical rehabilitation the process of restoring to the fullest possible degree the physical functioning of an individual who has a physiological or anatomical impairment.

medical social worker

medical social worker a licensed social worker, usually with a master’s degree in social work, who assists patients and their families with health-related problems in such areas as employment, finances, living arrangements, marriage, child care, social life, and emotional adjustment.

medical tourism

medical tourism travel to another country or location to obtain surgery (e.g., hip replacement) or other medical treatment (e.g., alternative cancer therapy) that is more expensive or unavailable in the country or location where the patient lives.

Medicare

Medicare n. a federal program of health insurance operated by the Centers for Medicare and Medicaid Services of the U.S. Department of Health and Human Services for those over 65, certain younger people with disabilities, and people with end-stage renal disease. Monies from payroll taxes and premiums from subscribers are deposited in trust funds to meet the expenses of the insured. Medicare consists of two basic programs: Part A includes inpatient costs and Part B provides supplementary medical insurance. Other options include a Medicare Advantage plan (Part C), in which medical services are covered by private health insurance companies in contract with Medicare, and an outpatient prescription drug plan (Part D).

medication

medication n. any drug available by prescription or over the counter to aid in the treatment of an illness, disease, disorder, or condition. Medications specifically used to treat mental health disorders tend to be prescribed therapeutic agents with psychoactive effects (see psychoactive drug). Overmedication—the taking of more than the prescribed dose of a drug or drugs—may occur when medication is not properly monitored. Self-medication is usually associated with individuals who use drugs or alcohol inappropriately to alleviate emotional problems. See also prescribing psychology.

medication-induced movement disorder

medication-induced movement disorder any movement disorder that occurs as an adverse effect of medication. It may involve rigidity, tremor, hypertonia (increased muscle tone), and other motor symptoms and is commonly seen after treatment with antipsychotic drugs. See tardive dyskinesia.

mediodorsal nucleus

mediodorsal nucleus see dorsomedial nucleus.

meditation

meditation n. profound and extended contemplation or reflection in order to achieve focused attention or an otherwise altered state of consciousness and to gain insight into oneself and the world. Traditionally associated with spiritual and religious exercises, meditation is now also used to provide relaxation and relief from stress; treat such symptoms as high blood pressure, pain, and insomnia; and promote overall health and well-being. See also concentrative meditation; mindfulness meditation; transcendental meditation.

medium

medium n. 1. the state of being in the middle of or between two factors or conditions or midway on some scale. 2. (pl. media) any means or agency through which messages are transmitted or information is diffused (e.g., the medium of television). 3. (pl. media) a substance, such as air or water, that serves to transmit a physical effect, such as sound or light. 4. (pl. media) a nutritive substance in which molds or other organisms are grown in a laboratory. 5. in spiritualism, a person who functions as the instrument of alleged communication between the living and the dead. Some mediums often claim paranormal abilities, such as clairvoyance, astral projection, or powers of psychic healing.

medium trance

medium trance see trance.

medium-wavelength pigment

medium-wavelength pigment the photopigment, present in one of the three populations of retinal cones, that has maximum sensitivity to a wavelength of 531 nm. The absence of the gene for the medium-wavelength pigment causes deuteranopia (red–green color blindness). See also long-wavelength pigment; short-wavelength pigment.

medulla

medulla n. 1. the central or innermost region of an organ, such as the adrenal medulla, the central portion of the adrenal gland. Compare cortex. 2. see medulla oblongata. —medullary adj.

medulla oblongata

medulla oblongata the most inferior (lowest), or caudal (tailward), part of the hindbrain. It contains many nerve tracts that conduct impulses between the spinal cord and higher brain centers, as well as autonomic nuclei involved in the control of breathing, heartbeat, and blood pressure. Also called myelencephalon.

medullary reticular formation

medullary reticular formation the hindmost portion of the brainstem reticular formation, implicated in motor control and copulatory behavior.

medullary sheath

medullary sheath see myelin sheath.

medullation

medullation n. see myelination.

mefloquine

mefloquine n. a chemical analog of quinine used in the treatment of malarial infections and prevention of malaria. It has been associated with seizures or psychological disturbances, including sleep disturbance, depression, panic attacks, and psychotic symptoms. Although such reactions are rare, mefloquine should not be taken by individuals with histories of depression, generalized anxiety disorder, psychosis, or seizure disorders. U.S. trade name: Lariam.

MEG

MEG abbreviation for magnetoencephalography or magnetoencephalograph.

mega-

Sorry, "mega" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

megadose pharmacotherapy

megadose pharmacotherapy a dosing strategy popular in the 1970s and 1980s in the United States and other countries, generally involving the rapid administration of very high doses of an antipsychotic drug in the hope that this would hasten an antipsychotic response. It was based on the presumption that rapid blockade of postsynaptic dopamine D2 receptors would lead to faster resolution of psychotic symptoms. This strategy was largely ineffective in producing a more rapid response and had numerous adverse effects, such as severe movement disorders and death due to neuroleptic malignant syndrome. Research published in the late 1980s showed that lower doses were as effective as higher doses and had fewer adverse consequences. Because of the lack of clinical benefit and the high incidence of adverse side effects associated with megadose pharmacotherapy, it has fallen into disuse. Also called rapid neuroleptization.

megalencephaly

megalencephaly n. an abnormally large, heavy, and usually malfunctioning brain. Large head size (macrocephaly) may be present at birth, or the head may become enlarged in early childhood. Symptoms of megalencephaly can include delayed development, seizures, and corticospinal (brain cortex and spinal cord) dysfunction. Hemimegalencephaly is a rare condition that is characterized by the enlargement of one side of the brain. Children with hemimegalencephaly may have a large and asymmetrical head, seizures, partial paralysis, and intellectual disability. Also called megalocephaly. —megalencephalic adj.

megalomania

megalomania n. a highly inflated conception of one’s importance, power, or capabilities, as can be observed in many individuals with mania and paranoid schizophrenia. In the latter, megalomania is often accompanied or preceded by delusions of persecution. See delusion of grandeur.

megalopsia

megalopsia n. see macropsia.

Megan’s law

Megan’s law an amendment to the Jacob Wetterling Crimes Against Children and Sexually Violent Offender Registration Act requiring that state registries of convicted but released sex offenders be disseminated to the public so that communities will be notified of offenders’ presence in a particular neighborhood. More formally known as the Community Notification Act, it was initially passed in New Jersey in 1994 after a repeat sex offender murdered a 7-year-old girl named Megan Nicole Kanka; it became a federal law in 1996.

megavitamin therapy

megavitamin therapy the use of very high doses of vitamins and mineral supplements, particularly vitamin C (ascorbic acid), nicotinic acid (niacin), vitamin B6 (pyridoxine), and magnesium, to treat certain mental disorders. Such an approach has not been widely adopted, and effectiveness is uncertain.

meiosis

meiosis n. a special type of division of the cell nucleus that occurs during the formation of the sex cells (ova and spermatozoa). During meiosis, a parental cell in the gonad produces four daughter cells that are all haploid; that is, they possess only one of each chromosome, instead of the normal diploid complement of homologous pairs of chromosomes. During the process of fertilization, the ova and spermatozoa undergo fusion, which restores the double set of chromosomes within the nucleus of the zygote thus formed. Compare mitosis.

Meissner’s corpuscle

Meissner’s corpuscle a type of small, oval sensory-nerve ending that is sensitive to touch. Meissner’s corpuscles are abundant in the fingertips, nipples, lips, and the tip of the tongue. [Georg Meissner (1829–1905), German anatomist and physiologist]

mel

mel n. a unit designed to measure the subjective extent of pitch. By definition, the pitch of a 1000 Hz tone presented at 40 dB SPL (40 phons) is 1000 mels. A tone whose frequency is judged to produce a pitch twice that of a 1000 mel tone has a pitch of 2000 mels, and so on. Across the range of orchestral instruments, the mel scale corresponds closely to the basic unit of the musical scale, the octave, so that doubling the frequency of a tone approximately doubles the number of mels.

melancholia

melancholia n. an archaic name for depression. —melancholic adj.

melancholia agitata

melancholia agitata a 19th-century term for catatonic excitement. It is occasionally still used for agitated depression.

melancholic features

melancholic features in DSM–IV–TR, characteristics that may be associated with a major depressive episode, including loss of pleasure in activities, sadness that worsens in the morning, early morning awakening, psychomotor agitation or retardation, loss of appetite or weight, and excessive guilt.

melancholic type

melancholic type the morose personality type that Galen attributed to an excess of black bile. See humoral theory.

melano- (melan-)

Sorry, "melano-melan" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

melanocortin-4 receptor (MC4-R)

Sorry, "melanocortin-4-receptor-mc4-r" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

melanocyte-stimulating hormone (MSH)

Sorry, "melanocyte-stimulating-hormone-msh" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

melatonin

melatonin n. an amine hormone, produced mainly by the pineal gland as a metabolic product of the neurotransmitter serotonin, that helps to regulate seasonal changes in physiology and may also influence puberty. It is implicated in the initiation of sleep and in the regulation of the sleep–wake cycle. Melatonin has been investigated in clinical studies as a hypnotic and for the management of circadian rhythm sleep disorders. Although these studies are as yet inconclusive, melatonin is widely available as an over-the-counter medication.

melioration

melioration n. in behavioral studies, allocating time to two or more activities such that local rates of reinforcement (i.e., reinforcers obtained per unit of time for each activity) are equal.

Mellaril

Mellaril n. a trade name for thioridazine.

Melnick–Needles syndrome

Melnick–Needles syndrome see otopalatodigital spectrum disorders.

melodic intonation therapy (MIT)

Sorry, "melodic-intonation-therapy-mit" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

member check

member check a procedure used in qualitative research whereby a researcher returns to a participant and requests feedback on his or her original responses as recorded and sometimes on their interpretation by others. Conducting a member check is intended to ensure the accuracy and internal validity of a qualitative study. However, some researchers question the merit of the process, viewing it as inconsistent with qualitative research in that it assumes participants’ experiences are objective and finite. Also called member validation; respondent validation.

membership group

membership group a social body or organization to which people belong as members, especially when they feel that the group has formally or informally accepted them into its ranks. Such groups, which include clubs, societies, cliques, teams, and political parties, often explicitly distinguish between individuals who belong to the group and those who do not. Compare aspirational group; reference group.

membrane

membrane n. a thin layer of tissue that covers a surface, lines a cavity, or connects or divides anatomical spaces or organs. One of the fundamental functions of a membrane is to contain the components within it. In cells, the membrane surrounds the cytoplasm and is composed of proteins and lipids. It is semipermeable and acts to control the passage of substances in and out of the cell (see ion channel).

membrane potential

membrane potential a difference in electric potential across a membrane, especially the plasma membrane of a cell. At rest, the membrane potential intracellularly is usually negative; that is, the inside of a cell membrane is comparatively negative versus the outside. See also resting potential.

membranous labyrinth

membranous labyrinth see labyrinth.

meme

meme n. a unit of practice or belief through which a society or culture evolves and that passes from one generation (or even one person) to the next. In this sense, the term—coined in 1976 by British biologist Richard Dawkins (1941– ) and derived from the Greek word for “imitation”—is a kind of metaphorical parallel to the term gene. Relatedly, an Internet meme is an idea (e.g., a word or phrase, hashtag, hyperlink, picture, or video), usually rooted in popular culture, that is widely popularized and distributed on the World Wide Web, for example, via social networks, blogs, e-mail, and news sources.

memorandum as a whole

memorandum as a whole see objective psychotherapy.

memorize

memorize vb. to commit to memory. Memorizing usually implies rote learning or drill as the method of learning, although use of an active mnemonic strategy is likely to be more effective. —memorization n.

memory

memory n. 1. the ability to retain information or a representation of past experience, based on the mental processes of learning or encoding, retention across some interval of time, and retrieval or reactivation of the memory. 2. specific information or a specific past experience that is recalled. 3. the hypothesized part of the brain where traces of information and past experiences are stored. See memory storage; memory system. See also explicit memory; immediate memory; implicit memory; long-term memory; short-term memory.

memory abilities

memory abilities abilities involved in remembering information, as assessed by tests of free recall (recall of words in any order), serial recall (recall of words in a fixed order), paired-associates learning (recall of a word paired with the word presented), and recognition memory (skill in stating correctly whether a presented word was previously presented on some list). Psychometric data suggest that, typically, various memory abilities are only weakly related to each other. Moreover, implicit memory is largely independent of explicit memory.

memory aid

memory aid see mnemonic.

memory attribution

memory attribution the ascribing of a memory to a source (e.g., a previously experienced event, another person, one’s imagination), depending on the source details retained in memory. Misattributions of memory can occur due to a number of factors (e.g., nonconscious influence of attitudes), resulting in a source monitoring error. Common examples of misattributions include cryptomnesia and false memory.

memory color

memory color any object’s color as modified in memory. The quality of remembered color often differs substantially from the actual hue. Color perception is considered to be a compromise between the memory color and present sensory input.

memory consolidation

memory consolidation see consolidation; perseveration–consolidation hypothesis.

memory curve

memory curve see retention curve.

memory decay

memory decay see decay theory.

memory disorder

memory disorder any impairment in the ability to encode, retain, or retrieve information or representations of experiences. A notable example is amnesia. Memory disorders may be partial or global, mild or severe, permanent or transitory, and anterograde (pertaining to difficulty with new information) or retrograde (pertaining to difficulty with previously known information). The causes include medical conditions leading to structural lesions of the brain or metabolic disruption of brain function, aging, psychological trauma, fugue states, or intrapsychic conflicts.

memory distortion

memory distortion any inaccurate or illusory recall or recognition, such as déjà vu, a false memory, or a memory illusion.

memory drum

memory drum a device formerly used to present items in memory experiments. The drum turned at a given speed, allowing one item at a time to be seen through an opening. The memory drum has been replaced by presentation of items on a computer screen.

memory illusion

memory illusion a distortion in remembering, analogous to a perceptual illusion, in which one remembers inaccurately or remembers something that in fact did not occur. The Deese–Roediger–McDermott paradigm is a memory illusion. See false memory.

memory impairment

memory impairment the loss of memory associated with a memory disorder.

memory retraining

memory retraining strategies to help individuals with neurological deficits improve their ability to process information in working memory. These strategies are typically applied with patients with brain injury or dementia and those with HIV/AIDS who are experiencing memory problems.

memory span

memory span the number of items that can be recalled immediately after one presentation. Usually, the items consist of letters, words, numbers, or syllables that the participant must reproduce in order. A distinction may be drawn between visual memory span and auditory memory span, depending on the nature of the presentation. See also Digit Span; operation span.

memory storage

memory storage the retention of memories in an organism. Historically, explanations of this process have included the continuous operation or “reverberation” of loops of neurons in cell assemblies (see cell assembly; reverberating circuit), the growth of new nerve endings grouped in synaptic knobs, and the encoding of information in complex molecules, such as RNA. Contemporary biological research suggests changes in synaptic efficiency as the basis of memory storage, as postulated in the research of Austrian-born U.S. neuroscientist Eric Kandel (1929– ).

memory system

memory system any of several different kinds of memory that are hypothesized to be located in separate brain areas and employed primarily in different sorts of memory tasks. Examples of hypothesized systems include working memory (a temporary store used in manipulating information), semantic memory (general knowledge), episodic memory (memories of one’s personal past), and procedural memory (habits and skills). See also perceptual representation system.

memory trace

memory trace a hypothetical modification of the nervous system that encodes a representation of information or a learning experience. See engram.

memory-enhancing drug

memory-enhancing drug see cognitive enhancer.

memory-operating characteristic curve (MOCC)

Sorry, "memory-operating-characteristic-curve-mocc" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

men’s liberation movement

men’s liberation movement a variety of social movements and positions united only by taking men and masculinity as their topic of interest. Some positions acknowledge the justice of feminist critiques of male dominance and recommend measures whereby men can overcome exploitation of women by men. Others aim to liberate men from stereotypical attitudes, particularly attitudes that prevent their expressing emotions and forming attachments to other men. A quite different type of movement seeks to help men rediscover traditional forms of masculinity and to become more responsible husbands and fathers. Yet another is essentially antifeminist, arguing that men are now subject to various injustices in education, employment, and the law (e.g., in divorce settlements and child-custody agreements). No one area of emphasis has become dominant under the rubric of men’s liberation.

menacme

menacme n. the period of a woman’s life cycle in which she experiences menstrual activity (i.e., from puberty to menopause).

ménage à trois

ménage à trois 1. a sexual relationship involving three people who are members of the same household. 2. three people having sex together (see troilism).

menarche

menarche n. the first incidence of menstruation in a female, marking the onset of puberty. The age at which menarche occurs varies among individuals and cultures: It tends to occur earlier in Western countries, possibly associated with better nutrition. —menarcheal adj.

Mendelian inheritance

Mendelian inheritance a type of inheritance that conforms to the basic principles developed around 1865 by Austrian monk Gregor Mendel (1822–1884), regarded as the founder of genetics. Mendelian inheritance is essentially determined by genes located on chromosomes, which are transmitted from both parents to their offspring. It includes autosomal dominant, autosomal recessive, and sex-linked inheritance. Mendel proposed two principles. The principle of segregation, or Mendel’s first law, states that recessive traits are neither modified nor lost in future generations as both dominant alleles and recessive alleles are independently transmitted and so are able to segregate independently during the formation of sex cells. The principle of independent assortment, or Mendel’s second law, states that there is no tendency for genes of one parent to stay together in future offspring.

Ménière’s disease

Ménière’s disease a disorder of balance and hearing due to excessive fluid in the inner ear, resulting in dizziness, nausea, tinnitus, and progressive deafness. [Prosper Ménière (1799–1862), French physician]

meninges

meninges pl. n. (sing. meninx) the three membranous layers that provide a protective cover for the brain and spinal cord. They consist of a tough outer dura mater, a middle arachnoid mater, and a thin, transparent pia mater, which fits over the various contours and fissures of the cerebral cortex.

meningioma

meningioma n. a benign brain tumor that develops in the arachnoid layer of the meninges, accounting for 15% to 25% of all tumors of the brain and spinal cord. Meningiomas are typically slow growing and cause damage mainly by pressure against the brain. Patients may complain of headaches or seizures as first symptoms.

meningitis

meningitis n. inflammation of the meninges, the three membranous layers that cover the brain and spinal cord, usually due to infection by bacteria, viruses, or fungi. Symptoms include high fever, nausea, vomiting, stiff neck, and headache. Bacterial meningitis includes meningococcal meningitis and tuberculous meningitis. Viral (or aseptic) meningitis is a milder nonbacterial disease; causes include the mumps, poliomyelitis, herpes viruses, and the echoviruses (which mainly affect young children during the summer). If untreated or not treated promptly, many types of meningitis can result in confusion, lethargy, coma, and eventually death.

meningocele

meningocele n. a congenital herniation (protrusion) of the meninges (the three membranous layers that cover the brain and spinal cord) through an abnormal opening in the skull or spinal cord, with seepage of cerebrospinal fluid into the protrusion. The disorder is sometimes associated with hydrocephalus or other neurological defects, which reduces the chances of a favorable prognosis. If the herniation contains neural tissue, the condition is identified as an encephalocele.

meningococcal meningitis

meningococcal meningitis see bacterial meningitis.

meningoencephalitis

meningoencephalitis n. inflammation of the brain and the meninges covering it.

meningomyelocele

meningomyelocele n. protrusion of the spinal cord and its covering meninges through a defect in the spinal column. This results in an external sac containing cerebrospinal fluid, poorly formed meninges, and a malformed spinal cord. Also called myelomeningocele. See spina bifida.

menkeiti

menkeiti n. see myriachit.

menopausal depression

menopausal depression severe dysphoria occurring during the female climacteric (menopause) or immediately before menopause (i.e., perimenopause), particularly among women who have had a prior tendency to depression.

menopause

menopause n. see climacteric. —menopausal adj.

menorrhagia

menorrhagia n. excessive bleeding during menstruation. Also called epimenorrhagia.

mens rea

mens rea the malicious or blameworthy state of mind (Latin, “guilty mind”) that must be proved in addition to the actus reus to establish criminal responsibility and secure a conviction. It involves a conscious disregard for the law, which is presumed to be known by the defendant. For some crimes, the mens rea may be recklessness or negligence rather than a deliberate intention to bring about certain consequences. Also called criminal intent.

Mensa

Mensa n. an organization of individuals whose sole admission requirement is an IQ in the upper 2% of the population.

menses

menses pl. n. see menstruation.

menstrual age

menstrual age the age of a fetus calculated from the beginning of the mother’s last menstruation. At full term, it is normally 280 days or 40 weeks—that is, usually 2 weeks longer than the gestational age.

menstrual cycle

menstrual cycle a modified estrous cycle that occurs in most primates, including humans (in which it averages 28 days). The events of the cycle are dependent on cyclical changes in the concentrations of gonadotropins secreted by the anterior pituitary gland, under the control of gonadotropin-releasing hormone, and can be divided into two phases. In the follicular phase, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) stimulate development of an ovum and secretion of estrogen within the ovary, in a graafian follicle, culminating in ovulation, which occurs halfway through the cycle. The estrogen stimulates thickening of the endometrium of the uterus in preparation to receive a fertilized ovum. The luteal phase begins immediately after ovulation, when the ruptured follicle becomes the corpus luteum and secretes progesterone, which inhibits further secretion of releasing hormone (and hence of FSH and LH). If fertilization does not occur, this phase ends with menstruation and a repeat of the follicular phase.

menstrual synchrony

menstrual synchrony the similar timing thought to occur in the menstrual cycles of women who live together or spend a lot of time together. Whether this phenomenon actually occurs is controversial.

menstrual taboo

menstrual taboo any culture-bound prohibition associated with menstruating women, typically involving physical separation from men, abstention from sexual intercourse, or the exclusion of women from certain daily activities (e.g., the preparation of food).

menstruation

menstruation n. a periodic discharge of blood and endometrial tissue from the uterus through the vagina that occurs in women as part of the menstrual cycle. Also called menses; menstrual (or monthly) period.

mental

mental adj. 1. of or referring to the mind or to processes of the mind, such as thinking, feeling, sensing, and the like. 2. phenomenal or consciously experienced. In contrast to physiological or physical, which refer to objective events or processes, mental denotes events known only privately and subjectively; it may refer to the cognitive processes involved in these events, to differentiate them from physiological processes.

mental aberration

mental aberration a pathological deviation from normal thinking, particularly as a symptom of a mental or emotional disorder.

mental abilities

mental abilities abilities as measured by tests of an individual in areas of spatial visualization, perceptual speed, number facility, verbal comprehension, word fluency, memory, inductive reasoning, and so forth, depending on the theory or test. See also primary ability.

mental accounting

mental accounting a cognitive process in which individuals track and evaluate their income and expenditures by grouping them into consumption categories or mental accounts: This in turn affects future transactions by influencing how economic activities are perceived. The topical organization of mental accounts leads people to evaluate gains and losses in relative rather than in absolute terms. For example, a person who finds that a $10 bill is missing while waiting in line to buy a $10 theater ticket is likely to buy the ticket anyway, whereas the same person might be unwilling to spend another $10 to repurchase a new theater ticket to replace one he or she lost. In such a case, going to the theater is viewed as a transaction in which the cost of the ticket is exchanged for the experience of seeing the play, so that buying a second ticket increases the cost of seeing the play to an unacceptable level; by contrast, the loss of the cash is not posted to the account of the play and it affects the purchase of a ticket only by making the individual feel slightly less affluent. Mental accounting is derived from prospect theory and one of several theoretical approaches to financial decision making. See behavioral finance.

mental age (MA)

Sorry, "mental-age-ma" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mental apparatus

mental apparatus see psychic apparatus.

mental asymmetry

mental asymmetry an imbalance in mental abilities, as in individuals with Williams syndrome, who may exhibit severe impairment in visuospatial abilities but possessing good to exceptional language abilities.

mental ataxia

mental ataxia see intrapsychic ataxia.

mental balance

mental balance integration of mental processes.

mental block

mental block see block.

mental chemistry

mental chemistry a concept proposed by John Stuart Mill as an alternative to the mental mechanics described by his father, James Mill. The concept is modeled on a common phenomenon in physical chemistry, in which two chemical substances combine to form a compound with properties not present in either of the components. Similarly, Mill held that compound ideas were not merely combinations of simpler ideas but that they possessed other qualities not present in any of the constituent ideas. Thus, such an idea could be an essentially new one. See associationism; association of ideas.

mental chronometry

mental chronometry see chronometric analysis.

mental claudication

mental claudication a temporary interruption of blood flow to a portion of the brain that results in brief episodes of mental status changes.

mental coaching

mental coaching in education, a field of teaching expertise, used mainly for counseling, business, and sports, that is focused on the direct cognitive features of behavior. It can improve overall performance, restore confidence, enhance motivation, reduce mental errors, and upgrade underperformance. It can also teach how to enhance concentration, overcome a slump or block in performance, focus better under pressure, and perform more consistently.

mental combination

mental combination in Piagetian theory, a type of cognitive processing typical of the final subphase of the sensorimotor stage, in which children of 18 to 24 months of age begin to use mental images to represent objects and to engage in mental problem solving. It facilitates the transition between the action-oriented world of the infant and the symbol-oriented world of the child. Also called invention of new means through mental combination.

mental confusion

mental confusion see confusion.

mental defective

mental defective an obsolete name for a person with an intellectual disability or learning disability.

mental deficiency

mental deficiency another (and now seldom used) name for intellectual disability, sometimes referring to severe or profound intellectual disability with known biological causes.

mental development

mental development the progressive changes in mental processes due to maturation, learning, and experience. See cognitive development.

mental diplopia

mental diplopia the experience of illusions, hallucinations, or false memories with concurrent awareness that these experiences are not real and are an abnormal occurrence.

mental disease

mental disease an obsolete name for a mental disorder.

mental disorder

mental disorder any condition characterized by cognitive and emotional disturbances, abnormal behaviors, impaired functioning, or any combination of these. Such disorders cannot be accounted for solely by environmental circumstances and may involve physiological, genetic, chemical, social, and other factors. Specific classifications of mental disorders are elaborated in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (see DSM–IV–TR; DSM–5) and the World Health Organization’s International Classification of Diseases. Also called mental illness; psychiatric disorder; psychiatric illness; psychological disorder. See also psychopathology.

mental effort

mental effort the amount of cognitive work required by a given task. See also cognitive load; effortful processing.

mental energy

mental energy see psychic energy.

mental examination

mental examination a comprehensive evaluation of an individual’s behavior, attitudes, and intellectual abilities for the purpose of establishing or ruling out pathology.

mental faculty

mental faculty see cognitive faculty; faculty psychology.

mental fog

mental fog see clouding of consciousness.

mental function

mental function any cognitive process or activity, such as thinking, sensing, or reasoning.

mental growth

mental growth the incremental improvement in a mental function, usually intelligence, with increasing age.

mental handicap

mental handicap impaired cognitive ability that interferes with independent functioning in the community. Use of the term is now generally discouraged in preference to intellectual disability.

mental healing

mental healing the process of alleviating or attempting to alleviate mental or physical illness through the power of the mind, typically using such methods as visualization, suggestion, and the conscious manipulation of energy flow. See also faith healing; psychic healing.

mental health

mental health a state of mind characterized by emotional well-being, good behavioral adjustment, relative freedom from anxiety and disabling symptoms, and a capacity to establish constructive relationships and cope with the ordinary demands and stresses of life. See also flourishing; normality.

Mental Health America (MHA)

Sorry, "mental-health-america-mha" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mental health care

mental health care a category of health care service and delivery provided by several fields involved in psychological assessment and intervention (psychology, psychiatry, neurology, social work, etc.). This type of care includes but is not limited to psychological screening and testing, psychotherapy and family therapy, and neuropsychological rehabilitation. Also called behavioral health care. See also mental health services.

mental health clinic

mental health clinic an outpatient facility for the diagnosis and treatment of psychological and behavioral problems.

mental health consultation

mental health consultation a model of mental health service provision to communities or specific settings (e.g., schools, organizations) in which a clinically trained mental health specialist acts as a consultant to assist and guide an individual or group of individuals (known as consultees; including professionals, such as teachers, nurses, primary care doctors, peer counselors, and employers, and nonprofessionals, such as parents or caregivers) in addressing a problem presented by clients under the consultees’ supervision or care (such as students, patients, employees, or family members). There is often a dual purpose to mental health consultation: (a) problem solving with a consultee on a specific mental health issue with a client and (b) giving the consultee added skills and insights that will enhance his or her future functioning in dealing with a client’s problems. Mental health consultation has several subtypes, including client-centered consultation, which focuses the consultant’s attention on effective intervention for the client; and consultee-centered consultation, in which the consultant focuses on remedying shortcomings in the consultee instead of solely addressing the problems of the client. See also behavioral consultation; consulting psychology. [developed by British physician Gerald Caplan (1917–2008)]

mental health counselor

mental health counselor a certified mental health professional who provides counseling services either independently or as part of a treatment team.

mental health nursing

mental health nursing see psychiatric nursing.

mental health parity

mental health parity in U.S. health care law, the mandate that the treatment limits and financial requirements that insurers apply to benefits for treatment of mental health and substance use disorders must not be more restrictive than those applied to medical and surgical benefits in group health plans that provide all such benefits to more than 50 employees.

mental health program

mental health program a treatment, prevention, rehabilitation, or educational service offered by a community mental health center or other entity for the purpose of maintaining or improving the mental health of an individual or community.

mental health services

mental health services any interventions—assessment, diagnosis, treatment, or counseling—offered in private, public, inpatient, or outpatient settings for the maintenance or enhancement of mental health or the treatment of mental or behavioral disorders in individual and group contexts.

mental health support organization

mental health support organization any organization established to give support to individuals living with mental illness. Such organizations provide access to mutual support groups and may also advocate for improved delivery of mental health services and improved access to such services, raise money for mental health research, and work to increase public awareness of mental health issues. The National Alliance on Mental Illness is an example. See also ex-patient club.

mental health worker

mental health worker a member of a mental health treatment team who assists professional staff in a wide range of services.

mental history

mental history a record of information relating to a person’s mental health (see case history). A mental history, which may be compiled by means of structured or unstructured interviews, usually covers the history of both the individual and family members.

mental hospital

mental hospital see psychiatric hospital. See also mental institution; private mental hospital; public mental hospital.

mental housecleaning hypothesis

mental housecleaning hypothesis the hypothesis that dreams support the reorganization of material learned during the prior waking period, particularly by simplifying and reducing overlapping information. [developed by U.S. psychiatrist J. Allan Hobson (1933– )]

mental hygiene

mental hygiene a general approach aimed at maintaining mental health and preventing mental disorder through such means as educational programs, promotion of a stable emotional and family life, prophylactic and early treatment services (see primary prevention), and public health measures. The term itself is now less widely used than formerly.

mental illness

mental illness see mental disorder.

mental imagery

mental imagery see imagery.

mental institution

mental institution a treatment-oriented facility in which patients with severe psychological disorder are provided with supervised general care and therapy by trained psychologists and psychiatrists as well as auxiliary staff. The patients of a mental institution will generally be those who are unable to function independently as outpatients when supported by psychoactive drugs. See also psychiatric hospital.

mental lexicon

mental lexicon the set of words that a person uses regularly (see productive vocabulary) or recognizes when used by others (see receptive vocabulary). Psycholinguistics has proposed various models for such a lexicon, in which words are mentally organized with respect to such features as meaning, lexical category (e.g., noun, verb), frequency, length, and sound. Also called lexical memory.

mental load

mental load see cognitive load.

mental map

mental map 1. a mental representation of the world or some part of it based on subjective perceptions rather than objective geographical knowledge. Such a map will normally prioritize the individual’s neighborhood, city, and nation and give prominence to more distant places according to personal experience (e.g., vacations), cultural connections (e.g., family history or language links), and the level of coverage in the mass media. The map will also incorporate the individual’s negative or positive feelings about these places, which will often reflect conventional ideas or stereotypes. Research suggests that mental maps vary widely with nationality, region, ethnicity, gender, education, and socioeconomic class. 2. any internal representation of two-dimensional or three-dimensional space. See cognitive map.

mental maturity

mental maturity the fully developed mental functioning of an average adult.

mental measurement

mental measurement the use of quantitative scales and methods in measuring psychological processes. Also called mental testing. See psychometrics.

mental mechanics

mental mechanics the concept, named and described by James Mill but common to most earlier associationist positions, that all complex ideas are merely agglomerations of simpler ideas combined according to the laws of association. Also called mental physics. Compare mental chemistry. See also associationism; association of ideas.

mental mechanism

mental mechanism in psychodynamics, the psychological functions, collectively, that help individuals meet environmental demands, protect the ego, satisfy inner needs, and alleviate internal and external conflicts and tensions. Among them are (a) language, which enables expression of thoughts; (b) memory, which stores information needed in solving problems; and (c) perception, which involves recognition and interpretation of phenomena. In addition, in psychoanalytic and psychodynamic theory, various defense mechanisms, such as rationalization and compensation, help to prevent anxiety and protect self-esteem.

mental model

mental model any internal representation of the relations between a set of elements, as, for example, between workers in an office or department, the elements of a mathematics or physics problem, the terms of a syllogism, or the configuration of objects in a space. Such models may contain perceptual qualities and may be abstract in nature. They can be manipulated to provide dynamic simulations of possible scenarios and are thought to be key components in decision making. In the context of ergonomics, for example, a mental model of a system or product would include its various attributes, rules for operation and handling, and expectations regarding use and consequences and would be used to guide the individual’s interactions with the system or product in question. See also shared mental model.

mental paper-folding test

mental paper-folding test a test that requires the participant to indicate what sheets of paper, with directions for folding, will look like once folded to form a three-dimensional shape. The test measures three-dimensional spatial visualization ability.

mental practice

mental practice the use of imagery to practice a specific skill whereby the performance of a task (e.g., a double lutz in figure skating) is visualized but not carried out.

mental process

mental process any process that takes place in the mind. This term is often used synonymously with cognitive process. See also higher mental process.

mental rehearsal

mental rehearsal the use of imagery to practice behavioral patterns or skills, for example, reacting without impatience to a request that seems unnecessary or performing a defensive play in basketball.

mental representation

mental representation a hypothetical entity that is presumed to stand for a perception, thought, memory, or the like during cognitive operations. For example, when doing mental arithmetic, one presumably operates on mental representations that correspond to digits and numerical operators; when one imagines looking at the reverse side of an object, one presumably operates on a mental representation of that object; when one repeats a phone number aloud while dialing it, one presumably operates on mental representations of the names of the digits. However, there is no consensus yet as to what mental representations might be. See thinking.

mental retardation (MR)

Sorry, "mental-retardation-mr" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mental rotation

mental rotation the ability to mentally manipulate stimuli some degree clockwise or counterclockwise from their normal orientations. This ability was originally measured using a laboratory task, developed by U.S. psychologist Roger Newland Shepard (1929– ), that required participants to make judgments about stimuli that had been rotated out of their normal orientation.

Mental scale

Mental scale see Bayley Scales of Infant and Toddler Development.

mental set

mental set 1. a temporary readiness to perform certain psychological functions that influences the response to a situation or stimulus, such as the tendency to apply a previously successful technique in solving a new problem. It is often determined by instructions but need not be. Essentially synonymous with the older term Einstellung, mental set is the embodiment of the earlier concepts of Aufgabe and determining tendency. 2. the situation in which a preparedness to perform one type of task causes a decrement in the ability to perform on some other category of task. See task switching.

mental shift

mental shift a switch from one mental set to another, as in moving from an arithmetic-based problem to one involving a simple numerical code. Research has shown that efficiency suffers noticeably when tasks require abrupt or frequent mental shifts.

mental status

mental status the global assessment of an individual’s cognitive, affective, and behavioral state as revealed by a mental examination that covers such factors as general health, appearance, mood, speech, sociability, cooperativeness, facial expression, motor activity, mental activity, emotional state, trend of thought, sensory awareness, orientation, memory, information level, general intelligence level, abstraction and interpretation ability, and judgment.

mental status examination (MSE)

Sorry, "mental-status-examination-mse" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mental synthesis

mental synthesis the process by which ideas and images are combined and formed into objects of thought, or by which objects of consciousness are brought together into meaningful wholes.

mental test

mental test 1. any test that measures one or more cognitive abilities. 2. an intelligence test.

mental testing

mental testing see mental measurement.

mental topography

mental topography see topographical psychology.

mental workload

mental workload see cognitive load.

mentalese

mentalese n. a hypothetical language of thought that combines cognitive and semantic systems and operates on concepts and propositions.

mentalism

mentalism n. a position that insists on the reality of explicitly mental phenomena, such as thinking and feeling. It holds that mental phenomena cannot be reduced to physical or physiological phenomena (see reductionism). The term is often used as a synonym for idealism, although some forms of mentalism may hold that mental events, although not reducible to physical substances, are nonetheless grounded in physical processes. Most modern cognitive theories are examples of this latter type of mentalism. Compare eliminativism; identity theory. See also conscious mentalism. —mentalist adj.

mentality

mentality n. 1. the capacity for thought. 2. an attitude or way of thinking, especially one that is seen as limited in some way.

mentalization

mentalization n. the ability to understand one’s own and others’ mental states, thereby comprehending one’s own and others’ intentions and affects. It has been theorized that this ability is a component of healthy personality development and is achieved through a child’s secure attachment to the parent. The concept has had particular application in the understanding and treatment of borderline personality disorder (BPD), characterized in this context as a disorder marked in part by an inability to mentalize due to poor attachment in early life. Mentalization-based treatment (MBT) is a psychodynamically oriented psychotherapy that was developed specifically to address mentalization deficits in patients with BPD; by mitigating these deficits, MBT aims to decrease the problems with impulse control and affect regulation that are common to such patients and to improve their interpersonal functioning. Also called reflective functioning. [proposed in 1996 by Hungarian-born British psychoanalyst Peter Fonagy (1952– )] —mentalize vb.

mentally defective

mentally defective 1. in some legal jurisdictions in the United States, a descriptor for persons who have a mental disorder or neurological deficit that renders them incapable of appraising the nature of their conduct. 2. an obsolete and pejorative descriptor for a person with intellectual disability.

mentation

mentation n. thinking or mental activity in general.

mentor

mentor n. an experienced person who provides instruction, encouragement, guidance, advice, and other support to, and helps develop the skills of, a less experienced person.

mentoring

mentoring n. the provision of instruction, encouragement, and other support to an individual (e.g., student, youth, colleague) to aid his or her overall growth and development or pursuit of greater learning skills, a career, or other educational or work-related goals. Numerous mentoring programs exist within occupational, educational, and other settings; they use frequent communication and contact between mentors and their respective protégés as well as a variety of techniques and procedures to develop productive relationships.

meperidine

meperidine n. a synthetic opioid used in the acute management of moderate to severe pain (see opioid analgesic). It is an agonist at the mu opioid receptor and has the side effects of other opioid analgesics. Fatal reactions have resulted when meperidine is administered to patients taking monoamine oxidase inhibitors (MAOIs), and it should therefore not be used in patients who have taken MAOIs within 14 days. Patients taking phenothiazine antipsychotics or tricyclic antidepressants concurrently with meperidine may experience severe respiratory depression. Also called pethidine. U.S. trade name (among others): Demerol.

mephedrone (4-methyl-N-methylcathinone)

Sorry, "mephedrone-4-methyl-n-methylcathinone" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mephenytoin

mephenytoin n. see hydantoin.

meprobamate

meprobamate n. one of the drugs introduced into the U.S. market in the early 1950s as an alternative to the barbiturates. It was commonly and widely prescribed in the 1950s and 1960s for daytime sedation and the treatment of anxiety. Meprobamate is a less potent respiratory depressant than the barbiturates unless taken in combination with other CNS depressants, such as alcohol and opioids. Like the barbiturates, use of meprobamate has been almost completely supplanted by the benzodiazepines. U.S. trade name: Miltown. See also sedative, hypnotic, and anxiolytic drug.

mercury switch

mercury switch an on–off interface between a device and the user that comprises a glass tube containing mercury with electrodes at one end. It can be attached to the hand, wrist, arm, or other body part of users with severe upper extremity disabilities and is activated by slight body movements that tilt it from a neutral position.

mercy

mercy n. kindness, compassion, or leniency toward a transgressor, toward someone over whom one has power or authority, or toward someone in distress.

mercy killing

mercy killing a direct action intended to end what would otherwise be the prolonged agony of a dying person or animal. The concept has been known since ancient times: Warriors often were expected to kill a desperately wounded comrade or enemy. Severely injured animals are also put out of their misery by mercy killing. See also assisted death; euthanasia.

mere-exposure effect

mere-exposure effect the finding that individuals show an increased preference (or liking) for a stimulus as a consequence of repeated exposure to that stimulus. This effect is most likely to occur when there is no preexisting negative attitude toward the stimulus object, and it tends to be strongest when the person is not consciously aware of the stimulus presentations. [identified in 1968 by Robert B. Zajonc]

mere-thought polarization

mere-thought polarization the finding that merely thinking about an attitude can result in polarization in the direction of that attitude. For example, thinking about a moderately positive attitude can result in that attitude becoming extremely positive. [originally demonstrated by U.S. psychologist Abraham Tesser (1941– )]

Meridia

Meridia n. a former trade name for sibutramine.

meridional amblyopia

meridional amblyopia an abnormal condition, caused by astigmatism, in which contours of oblique orientation appear sharply focused whereas other orientations (vertical and horizontal) appear blurred, even when the astigmatism is optically corrected. This indicates that the astigmatism, prior to optical correction, altered orientation-selective mechanisms in the visual cortex in a direction favoring oblique over horizontal and vertical orientations. Presumably, individuals with meridional amblyopia have a paucity of cortical cells tuned to vertical and horizontal orientations.

Merital

Merital n. a former trade name for nomifensine.

meritocracy

meritocracy n. a political or social system in which rewards are given to individuals on the basis of their accomplishments. —meritocratic adj.

Meritor Savings Bank v. Vinson

Meritor Savings Bank v. Vinson a case resulting in an influential 1986 U.S. Supreme Court ruling that a hostile work environment constitutes sexual harassment and that victims do not bear the burden of demonstrating they were harmed by the harassment.

Merkel’s corpuscle

Merkel’s corpuscle see Merkel’s tactile disk.

Merkel’s law

Merkel’s law the principle that equal suprathreshold (above-threshold) differences in sensation correlate with equal differences in stimuli intensity. [Julius Merkel (1834–1900), German psychologist]

Merkel’s tactile disk

Merkel’s tactile disk a type of sensory-nerve ending in the glabrous skin of the hands and feet and in the hairy skin. Also called Merkel’s corpuscle; Grandry–Merkel corpuscle. [Friedrich Siegmund Merkel (1845–1919), German anatomist; M. Grandry, 19th-century Belgian physician]

merycism

merycism n. see rumination.

mescal buttons

mescal buttons see peyote.

mescaline

mescaline n. a hallucinogen derived from the peyote cactus and long used by indigenous peoples of the southwestern United States and Central America as part of certain religious ceremonies. Its effects often include nausea and vomiting as well as visual hallucinations involving lights and colors; they have a slower onset than those of LSD and usually last 1 to 2 hours. Mescaline is the oldest classic hallucinogen known to Western science; its pharmacology was defined in 1896, and its structure was verified by synthesis in 1919. It is a substituted phenylethylamine, and its likely mechanism of action is via serotonin and dopamine receptors. Mescaline is classified by the U.S. Drug Enforcement Administration as a Schedule I controlled substance (see scheduled drug).

mesencephalic nucleus

mesencephalic nucleus one of the three nuclei of the trigeminal nerve. It extends through the pons into the lower part of the midbrain (mesencephalon), and its fibers innervate the muscles and joints of the head.

mesencephalic tegmentum

mesencephalic tegmentum a region of the dorsal midbrain (mesencephalon) with neural connections between the cerebrum, spinal cord, thalamus, and subthalamus, forming an indirect corticospinal tract.

mesencephalon

mesencephalon n. see midbrain. —mesencephalic adj.

mesial temporal lobe epilepsy

mesial temporal lobe epilepsy see limbic epilepsy.

mesmerism

mesmerism n. a therapeutic technique popularized in the late 18th century by Franz Anton Mesmer, who claimed to effect cures through the use of a vitalistic principle that he termed animal magnetism. The procedure involved the application of magnets to ailing parts of a patient’s body and the induction of a trancelike state by gazing into the patient’s eyes, making certain “magnetic passes” over him or her with the hands, and so forth. Variants of mesmerism remained popular for much of the 19th century, when they were gradually superseded by hypnosis. —mesmerist n. —mesmeric adj. —mesmerize vb.

meso- (mes-)

Sorry, "meso-mes" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mesocephalic

mesocephalic adj. see cephalic index. —mesocephaly n.

mesocortical system

mesocortical system a network of dopaminergic neurons in the brain that consists of the medial prefrontal cortex and the anterior cingulate cortex. It has connections to other parts of the limbic system, including the nucleus accumbens, nuclei of the stria terminalis, and amygdala. It receives input from the ventral tegmental area, and its activity is related to emotion, reward, and substance abuse.

mesoderm

mesoderm n. the middle of the three primary germ layers of an animal embryo at the gastrula stage, lying between the ectoderm and endoderm. It develops into cartilage and bone, connective tissue, muscle, blood vessels and blood cells, the lymphatic system, gonads, and the excretory system. —mesodermal adj.

mesokurtic

mesokurtic adj. describing a frequency distribution that is neither flatter nor more peaked than the normal distribution. That is, a mesokurtic arrangement of values follows a bell-shaped curve, with the majority of scores clustered around a value at the midpoint and a few extreme scores tapering off on either side. See also platykurtic; leptokurtic.

mesolimbic system

mesolimbic system a network of dopaminergic neurons in the brain consisting of the nucleus accumbens, amygdala, and olfactory tubercle. It receives input from the ventral tegmental area and its activity is related to emotion, reward, and substance abuse.

mesomorph

mesomorph n. a constitutional type (somatotype) in Sheldon’s constitutional theory of personality characterized by a muscular, athletic physique, which—according to this theory—is highly correlated with somatotonia. Also called mesomorphic body type. See also body-build index. —mesomorphic adj. —mesomorphy n.

mesontomorph

mesontomorph n. a constitutional body type characterized by a broad, stocky body, roughly equivalent to a mesomorph. —mesontomorphic adj.

mesopic vision

mesopic vision vision that involves aspects of both photopic vision and scotopic vision, thus being mediated by both rods and cones.

mesoridazine

mesoridazine n. a conventional antipsychotic of the piperidine phenothiazine class. Mesoridazine is a low-potency agent that is a metabolic product of thioridazine. Like the latter drug, its use is associated with life-threatening disturbances in heart rhythm (prolongation of the Q-T interval potentially leading to torsades de pointes syndrome; see electrocardiographic effect). It should not be administered to individuals taking other drugs that prolong the Q-T interval or who have a history of heart rhythm disturbances, and it is appropriate for the treatment of schizophrenia only in individuals who have not responded to other antipsychotic agents. U.S. trade name: Serentil.

mesoskelic

mesoskelic adj. denoting a constitutional body type that is intermediate between brachyskelic (see brachyskeletal) and macroskelic and roughly equivalent to the athletic type in Kretschmer typology. [described by French physician L. P. Manouvrier (1850–1927)]

mesosomatic

mesosomatic adj. denoting an individual whose body build is within one standard deviation of the mean after scores for height and chest measurements have been multiplied (see body-build index).

mesostriatal system

mesostriatal system a set of dopaminergic neurons whose axons arise from the midbrain and innervate the basal ganglia. It includes neurons connecting the substantia nigra to the striatum (see nigrostriatal tract).

mesosystem

mesosystem n. in ecological systems theory, the groups and institutions outside the home (e.g., day care, school, a child’s peer group) that influence the child’s development and interact with aspects of the microsystem (e.g., relations in the home). Compare chronosystem; exosystem; macrosystem. [introduced by Urie Bronfenbrenner]

message factors

message factors characteristics of a persuasive message that can influence the effectiveness of the message itself. Such characteristics include whether the message is one-sided or two-sided (see one-sided message) and whether or not it is a rhetorical-question message.

message-learning approach

message-learning approach a theory that conceptualizes attitude change as a type of learning process in which the extent of attitude change is determined by how well the arguments in a persuasive message are learned. This process is seen as having five steps: exposure, attention, comprehension, yielding, and retention. The theory postulates that performance of these steps can be affected by four different types of variables: source factors, message factors, channel factors, and recipient factors. Also called Hovland model; Yale model. [originally developed by Carl I. Hovland and his colleagues at Yale University]

messenger RNA (mRNA)

Sorry, "messenger-rna-mrna" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

Messiah complex

Messiah complex the desire and compulsion to redeem or save others or the world. The individual may harbor the delusion of being divine. See also Jehovah complex.

Mestinon

Mestinon n. a trade name for pyridostigmine.

MET

MET symbol for metabolic equivalent.

meta- (met-)

Sorry, "meta-met" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

meta-analysis

meta-analysis n. a quantitative technique for synthesizing the results of multiple studies of a phenomenon into a single result by combining the effect size estimates from each study into a single estimate of the combined effect size or into a distribution of effect sizes. For example, a researcher could conduct a meta-analysis of several studies on the association between self-efficacy and achievement, integrating the findings into an overall correlation. Although meta-analysis is ideally suited for summarizing a body of literature in terms of its impact, limitations, and implications, there are conditions that limit its applicability. For example, there is no minimum number of studies nor participants required, and information of potential interest may be missing from the original research reports upon which the procedure must rely.

meta-attention

meta-attention n. awareness of the factors that influence one’s attention.

metabolic anomaly

metabolic anomaly see inborn error of metabolism.

metabolic defect

metabolic defect any deficiency in the structure or enzymatic function of protein molecules or in the transport of substances across cell membranes due to inborn errors of metabolism or disturbances caused by toxic agents or dietary excesses (e.g., alcoholism, cholesterol-rich foods).

metabolic disorder

metabolic disorder a disruption in the body’s physical and chemical processing of food into energy (see metabolism), caused when one or more organs (e.g., liver, pancreas) do not function properly. Metabolic disorders may be congenital (e.g., cystic fibrosis, sickle-cell anemia, Tay–Sachs disease) or acquired (e.g., some cases of nonalcoholic fatty liver disease).

metabolic encephalopathy

metabolic encephalopathy a form of encephalopathy arising from a metabolic disorder. Also called toxic-metabolic encephalopathy.

metabolic equivalent

metabolic equivalent (symbol: MET) a unit of measurement of heat, or energy, produced by the body: 1 MET = 50 kcal/h/m2 body surface. MET units are used to assess the expenditure of oxygen in a given activity; for example, 1 MET indicates that the body is at rest, 3 to 5 units would indicate light work, and more than 9 units indicates heavy work.

metabolic rate

metabolic rate the rate of use of energy of an organism during a given period. It is measured in kilojoules or kilocalories per day. See also basal metabolism.

metabolic screening

metabolic screening examination procedures used in predicting or diagnosing a possible inborn error of metabolism (e.g., phenylketonuria). The procedures include routine blood tests for newborns, genetic counseling of parents with known familial metabolic deficiencies, and amniocentesis.

metabolic syndrome

metabolic syndrome a collection of conditions that increases an individual’s risk for cardiovascular disease, stroke, and Type 2 diabetes. These include hypertension, elevated insulin levels, nonalcoholic fatty liver disease, and obesity. Metabolic syndrome may be congenital, acquired, or both.

metabolic tolerance

metabolic tolerance see pharmacodynamic tolerance.

metabolic–nutritional model

metabolic–nutritional model a system of studying mental disorders in which the emphasis is on long-term assessments of the influence of such factors as toxins and deprivations in populations.

metabolism

metabolism n. the physical and chemical processes within a living cell or organism that are necessary to maintain life. It includes catabolism, the breaking down of complex molecules into simpler ones, often with the release of energy; and anabolism, the synthesis of complex molecules from simple ones. See also basal metabolism; carbohydrate metabolism; fat metabolism; protein metabolism. [term coined by German physiologist Theodor Schwann (1810–1882)] —metabolic adj.

metabolite

metabolite n. a substance necessary for, involved in, or produced by metabolism.

metabotropic receptor

metabotropic receptor a neurotransmitter receptor that does not itself contain an ion channel but may use a G protein to open a nearby ion channel. See glutamate receptor. Compare ionotropic receptor.

metachromatic leukodystrophy

metachromatic leukodystrophy an autosomal recessive disorder (see recessive allele) characterized by deficiency or absence of the enzyme arylsulfatase A, which results in loss of myelin in the nervous system and accumulation of cerebroside sulfate (a type of myelin lipid) within the white matter of the central nervous system. Loss of motor function and deterioration in mental ability most commonly develop after the 1st year of life (late infantile form), but symptoms may also appear between 3 and 10 years of age (juvenile form) or around age 30 (adult form).

metacognition

metacognition n. awareness of one’s own cognitive processes, often involving a conscious attempt to control them. The tip-of-the-tongue phenomenon, in which one struggles to retrieve something that one knows one knows, provides an interesting and common example of metacognition. —metacognitive adj.

metacognitive model of attitudes (MCM)

Sorry, "metacognitive-model-of-attitudes-mcm" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

metacommunication

metacommunication n. auxiliary or covert messages, usually conveyed in the form of subtle gestures, movements, and facial expressions, about the procedural aspects or the dynamics (rather than the actual content) of communication between two or more parties. For example, a manager may respond to an employee’s request for help by looking annoyed, thus indicating displeasure that the employee could not handle the situation alone.

metacontrast

metacontrast n. a form of backward masking in which the perception of a visible stimulus (the target) is altered by the subsequent presentation of a second visual stimulus (the mask) in a different spatial location. The target is often a small dot, while the mask is a ring that surrounds it. Each stimulus is presented very briefly (10–100 ms), at intervals that are varied systematically, and the quality of the target’s percept is measured. Compare paracontrast.

metacriterion

metacriterion n. a suggested criterion, proposed by Hungarian-born philosopher Imre Lakatos (1922–1974), for evaluating competing understandings of science. Lakatos derived his metacriterion from the use of similar criteria in the evaluation of competing philosophical theories and proposed it as an alternative to both the falsificationism of Austrian-born British philosopher Karl Popper (1902–1994) and the historical theories of science of U.S. philosopher Thomas Kuhn (1922–1996). According to the metacriterion, a theory of science should be preferred to its competitors if it (a) makes more rational sense of the history of scientific practice and findings and (b) can be shown to lead to the discovery of more novel historical facts.

Metadate

Metadate n. a trade name for methylphenidate.

metaemotion

metaemotion n. one’s awareness of and attitude toward one’s own and others’ emotions. For example, some people have negative attitudes toward anger in themselves or anyone else; others like to encourage anger. Some are ashamed of being too happy; others strive for such a state.

metaesthetic range

metaesthetic range the range of weak pain sensations just below the level of obvious, unmistakable pain.

metaethics

metaethics n. see ethics.

metaevaluation

metaevaluation n. in evaluation research, an attempt to make judgments on the worth of an evaluation process with regard to its value and usefulness and its reliance on accepted evaluation standards. This involves a systematic evaluation that focuses on assessing methodological rigor, utility, cost, relevance, scope, importance, credibility, timeliness, and pervasiveness of dissemination.

metagnomy

metagnomy n. the divination of knowledge of the past or present by means other than the five senses, such as extrasensory perception.

metalanguage

metalanguage n. 1. a language or set of symbols that is used to describe another language or set of symbols. Examples are English words used in teaching a foreign language, the instructions that accompany a computer program, and the use of mathematical symbols to analyze the logic of an argument (see symbolic logic). Also called second-order language. 2. any use of language to discuss or analyze language, as in formal linguistic study, literary criticism, or the attempts of speakers to make sure that they understand one another correctly (e.g., “When you said the book was unreadable, were you referring to the print quality or the author’s style?”).

metalinguistic awareness

metalinguistic awareness a conscious awareness of the formal properties of language as well as its functional and semantic properties. It is associated with a mature stage in language and metacognitive development (see metacognition) and does not usually develop until around age 8. The arrival of metalinguistic awareness is often signaled by an interest in puns and word games. Also called linguistic awareness.

metamemory

metamemory n. awareness of one’s own memory processes, often involving a conscious attempt to direct or control them. It is an aspect of metacognition.

metamorphopsia

metamorphopsia n. a visual disorder in which objects appear to be distorted in size (see micropsia; macropsia), contour (e.g., irregular wavy edges), position (e.g., tilted), distance (see teleopsia), and color (e.g., fading of colors). Metamorphopsia can result from a variety of causes but frequently is due to displacement of the retina.

metamorphosis

metamorphosis n. a change in form or structure, typically from one developmental stage to another. See also sexual metamorphosis. —metamorphose vb.

metamotivation

metamotivation n. in the humanistic psychology of Abraham Maslow, those motives that impel an individual to “character growth, character expression, maturation, and development,” operating on the level of self-actualization and transcendence in the hierarchy of needs (see Maslow’s motivational hierarchy). In Maslow’s view, metamotivation is distinct from the motivation operating in the lower level needs, which he calls deficiency motivation, and it emerges after the lower needs are satisfied. Also called being motivation; B-motivation; growth motivation. See also Maslow’s theory of human motivation.

metaneed

metaneed n. in the humanistic psychology of Abraham Maslow, the highest level of need that comes into play primarily after the lower level needs have been met. Metaneeds constitute the goals of self-actualizers and include the needs for knowledge, beauty, and creativity. In Maslow’s view, the inability to fulfill them results in metapathology. Also called being value; B-value. See also Maslow’s motivational hierarchy; Maslow’s theory of human motivation.

metapathology

metapathology n. in the humanistic psychology of Abraham Maslow, the state of vague frustration or discontent experienced by individuals who are unable to satisfy their metaneeds (e.g., specific creative, intellectual, or aesthetic needs). See also metamotivation; Maslow’s theory of human motivation.

metaphor

metaphor n. a figure of speech (see figurative language) in which a word or phrase is applied to an object, person, or action that it does not literally denote (e.g., the journey of life) for the purpose of creating a forceful analogy. If the analogy is explicitly stated as such (e.g., life is like a journey), the figure is not a metaphor but a simile. —metaphorical or metaphoric adj.

metaphor therapy

metaphor therapy a system that focuses on the symbolic meaning of language and the use of metaphors in therapy. It is theorized that metaphors may provide means for restructuring thinking and approaches to problem solving in treatment. See also cryptophoric symbolism. [developed by U.S. psychotherapist Richard R. Kopp (1942–2012)]

metaphoric symbolism

metaphoric symbolism see cryptophoric symbolism.

metaphysics

metaphysics n. the branch of philosophy that deals with the question of the nature of ultimate reality; as such, it is considered to be the most abstract and speculative branch of philosophy. Metaphysics was the founding project of Greek philosophy and thus of the Western intellectual tradition as a whole. The term derives from the Greek, meaning “above (or beyond) the physical.” Early metaphysical philosophy, most notably that of Plato (c. 427–c. 347 bce), suggested a reality above the physical world that accounts for and gives rise to physical reality (see Platonic idealism). Later metaphysical conceptions have emphasized, as the ultimate foundation of reality, constructs as varied as mind, spirit, abstract principles, and physical matter. Since the time of René Descartes, the main focus of Western philosophy has shifted from metaphysics to epistemology, the study of the nature and limitations of knowledge; this is largely owing to a recognition that meaningful answers to questions of ultimate reality depend upon the working out of criteria (an epistemology) by which such answers can be judged as true. Nevertheless, any scholarly discipline, including psychology, that makes a claim of discovering or explaining the ultimate nature or origin of a phenomenon may be said to be engaged in metaphysics. —metaphysical adj.

metapsychics

metapsychics n. 1. the study of purported mental phenomena and abilities that are beyond the limits of orthodox psychological understanding, such as telepathy and the survival of the human psyche after death. The term has now generally been superseded by parapsychology. 2. people who are or appear to be exceptionally gifted in one or more paranormal abilities. See psychic.

metapsychological profile

metapsychological profile in psychoanalysis, a systematic profile of a patient’s intrapsychic functioning, in contrast to a mere list of symptoms; such a profile offers a picture of his or her entire personality. The technique was developed by Anna Freud in 1965.

metapsychology

metapsychology n. the study of, or a concern for, the fundamental underlying principles of any psychology. The term was used by Sigmund Freud to denote his own psychological theory, emphasizing its ability to offer comprehensive explanations of psychological phenomena on a fundamental level. Freud’s criteria for a metapsychology were that it should explain a psychical phenomenon in terms of (a) its dynamics, (b) its topology, and (c) its economic aspects. Although these specific criteria apply most clearly to Freud’s own theory, the notion of metapsychology as explanation at a fundamental and comprehensive level continues to be a useful construct. —metapsychological adj.

metastasis

metastasis n. see cancer.

metatheory

metatheory n. a higher order theory about theories, allowing one to analyze, compare, and evaluate competing bodies of ideas. The concept of a metatheory suggests that theories derive from other theories, so that there are always prior theoretical assumptions and commitments behind any theoretical formulation. It follows that these prior assumptions and commitments are worthy of study in their own right, and an understanding of them is essential to a full understanding of derivative theories. —metatheoretical adj.

metathetic

metathetic adj. 1. denoting a stimulus dimension in which a change of magnitude can cause a qualitative change in the psychological experience produced. For example, a faint smell may be quite pleasing, whereas an increase in intensity may cause revulsion. Compare prothetic. 2. relating to a change in place or condition, particularly the transposition of two phonemes in a word or the exchange of elements between chemical compounds to create different kinds of compounds. —metathesis n.

metaworry

metaworry n. 1. persistent worry about one’s own thoughts and cognitive processes. 2. a negative metacognitive process in which one worries about one’s own worrying and about its potentially harmful effects on oneself. According to British psychologist Adrian Wells, who first described this process in 1994, it contributes to the development of generalized anxiety disorder.

metempirical

metempirical adj. describing or pertaining to knowledge that is not subject to verification by experience and thus cannot be established by the methods of science. As described by British writer George Henry Lewes (1817–1878), the metempirical is roughly equivalent to the notion of the transcendent developed by German philosopher Immanuel Kant (see noumenon; transcendence).

metempsychosis

metempsychosis n. transmigration of the soul, whereby upon death a soul takes up residence in another body, human or animal. The belief is inherent in the doctrine of samsara, the cycle of birth, life, death, and rebirth, that is central to Hinduism and Buddhism. An important and unanswerable issue attends the doctrine: the extent to which the reincarnated soul retains its memories and personality. In the ancient Western world, a similar belief in multiple lives was taught by Greek philosophers Pythagoras (c. 569–c. 475 bce) and Empedocles (c. 493–c. 453 bce). See also reincarnation.

metencephalon

metencephalon n. the portion of the brainstem that includes the pons and cerebellum. With the medulla oblongata, the metencephalon forms the hindbrain. —metencephalic adj.

meth

meth n. slang for methamphetamine.

methadone

methadone n. a synthetic opioid analgesic that is used for pain relief and as a substitute for heroin and other opioids in methadone maintenance therapy. It is quite effective when orally ingested and has a long duration of action, both preventing withdrawal symptoms and blocking the reinforcing effects of these opioids. U.S. trade name (among others): Dolophine.

methadone maintenance therapy

methadone maintenance therapy a drug-rehabilitation therapy in which those with dependence on heroin and other opiates are prescribed a daily oral dose of methadone to blunt craving for these drugs and to diminish withdrawal symptoms. A controversial treatment, it is nonetheless widely considered the most effective approach to heroin addiction. The use of an opioid partial agonist, buprenorphine, particularly in combination with naloxone, is increasing as an alternative to methadone maintenance therapy.

methamphetamine

methamphetamine n. a CNS stimulant whose chemical structure is similar to that of amphetamine. It is used for treating attention-deficit/hyperactivity disorder in children and as a short-term aid to obesity treatment in adults. Like all amphetamines, methamphetamine is prone to abuse and dependence. It can be smoked, snorted, ingested orally, or injected. After the initial rush—it increases activity levels and induces a general sense of well-being—a state of high agitation that can lead to violence is experienced by some users. Long-term abuse is associated with nerve damage and behavioral and mental status changes, including psychosis. U.S. trade name: Desoxyn.

methaqualone

methaqualone n. a synthetic drug with sedative and hypnotic effects, unrelated chemically to other sedatives and having a potency roughly equal to that of pentobarbital. It is used to treat patients who are unable to tolerate barbiturate drugs. In small doses, the drug depresses the sensory cortex; in larger doses, it affects the spinal reflexes. Its clinical use peaked during the 1960s and 1970s, but due to its potential for abuse—it became a popular recreational drug (street name: lude)—it was classified as a Schedule I controlled substance in 1984, which ended its legal availability in the United States. Trade name (among others): Quaalude. See sedative, hypnotic, and anxiolytic drug.

methocarbamol

methocarbamol n. a member of a group of centrally acting muscle relaxants used as an adjunctive agent in the management of musculoskeletal pain. Because methocarbamol does not directly reduce skeletal muscle tension, its therapeutic action is thought to be due to its sedative or CNS depressant properties. It is available in tablet and injectable forms. U.S. trade name: Robaxin.

method of absolute judgment

method of absolute judgment a psychophysical procedure in which stimuli are presented in random order to a participant, whose task is to place each stimulus in a particular category. The stimuli usually vary along one or two dimensions, such as brightness or loudness. Also called absolute-judgment method.

method of adjustment

method of adjustment a psychophysical technique in which the participant adjusts a variable stimulus to match a constant or standard. For example, the observer is shown a standard visual stimulus of a specific intensity and is asked to adjust a comparison stimulus to match the brightness of the standard. Also called adjustment method; error method; method of average error; method of equivalents.

method of agreement

method of agreement the first of the five canons of empirical science laid down by John Stuart Mill. It is meant to establish necessary conditions for a phenomenon. For example, if every instance of an effect E1 (E2, E3, etc.) had in common a particular condition C1, and it is observed that among all cases of E, only C1 and no other conditions (C2, C3, etc.) were common, it can be concluded that C1 is the necessary condition for E. See Mill’s canons.

method of agreement and difference

method of agreement and difference the third of the five canons of empirical science laid down by John Stuart Mill. It enables the discovery of necessary and sufficient conditions for a phenomenon by combining the first two of Mill’s canons: the method of agreement and the method of difference.

method of average error

method of average error see method of adjustment.

method of choice

method of choice a psychophysical procedure in which the participant is presented with several arrays of stimuli, one of which contains the target stimulus. The participant’s task is to choose the array that contains the target stimulus.

method of concomitant variation

method of concomitant variation the fifth of the five canons of empirical science laid down by John Stuart Mill. It is meant to establish the causal relationship between phenomena. It holds that if there is a functional relationship between a condition C1 and an effect E1, it may be inferred that there is a causal relationship between one or more of the elements that make up C1 and the resultant E1. Which element of C1 is causal can be established by implementing the rest of Mill’s canons. This strategy is essentially the foundation of modern approaches to experimentation in psychology and is directly related to the problems of inferring causality from correlation.

method of constant adjustment

method of constant adjustment see method of limits.

method of constant stimuli

method of constant stimuli a psychophysical procedure for determining the sensory threshold by randomly presenting several stimuli known to be close to the threshold. The threshold is the stimulus value that was detected 50% of the time. Also called constant stimulus method; method of right and wrong cases. See also method of limits.

method of difference

method of difference the second of the five canons of empirical science laid down by John Stuart Mill. It is meant to establish sufficient conditions for a phenomenon. For example, if under one condition, C1, an effect, E1, does not occur, and as C1 is changed to C2 the effect E1 does occur, it may be concluded that C2 is a sufficient cause of E1, and the alternative hypothesis, that C1 causes E1, can be eliminated. Thus, the effect is attributed to the “difference” between conditions C1 and C2. Also called difference canon.

method of equal and unequal cases

method of equal and unequal cases in psychophysics, a variation of the method of constant stimuli requiring judgment of paired stimuli as equal or unequal.

method of equal-appearing intervals

method of equal-appearing intervals in psychophysics, a procedure in which magnitudes between pairs of stimuli are adjusted so that the differences between stimuli within each pair are perceived as equal. Also called method of equal sense differences; method of mean gradations.

method of equivalents

method of equivalents see method of adjustment.

method of exclusion

method of exclusion a principle by which empirical observation can eliminate (or exclude) possible causes for a phenomenon and thereby reach conclusions about the true cause. The principle is attributed to Francis Bacon, who proposed an inductive method (see induction) in which the observer lists both positive and negative instances of a phenomenon and then attempts to infer a common factor that is present in the positive instances and absent in the negative instances. Thus, the cause of the phenomenon is established by a method of exclusion of negative instances. See Baconian method. See also Mill’s canons.

method of just noticeable differences

method of just noticeable differences a psychophysical procedure to determine the smallest difference between stimuli that can be perceived. A standard stimulus is presented together with a variable stimulus whose magnitude is increased in some trials and decreased in others until a just perceptible difference between the stimuli is reported. The average of the two series is taken, and the threshold is calculated as the point where the difference can be recognized 50% of the time. Also called method of serial exploration.

method of limits

method of limits a psychophysical procedure for determining the sensory threshold by gradually increasing or decreasing the magnitude of the stimulus presented in discrete steps. That is, a stimulus of a given intensity is presented to a participant; if it is perceived, a stimulus of lower intensity is presented on the next trial, until the stimulus can no longer be detected. If it is not perceived, a stimulus of higher intensity is presented, until the stimulus is detected. The threshold is the average of the stimulus values at which there is a detection-response transition (from yes to no, or vice versa). An alternative procedure, the method of constant adjustment, allows the participant to adjust a stimulus continuously until it can no longer be perceived. See also method of constant stimuli.

method of loci

method of loci a mnemonic technique in which the items to be remembered are converted into mental images and associated with specific positions or locations. For instance, to remember a shopping list, each product could be imagined at a different location along a familiar street.

method of moments

method of moments an alternative to maximum likelihood estimation in which values describing basic characteristics of a sample (known as moments) are used to approximate the corresponding values for the larger population. For example, a researcher could use the method of moments to estimate the mean or variance for a population by inserting the appropriate sample value into an equation that calculates one from the other. Although simpler than maximum likelihood, the method of moments is less accurate.

method of opposition

method of opposition see process-dissociation procedure.

method of ratio estimation

method of ratio estimation a psychophysical procedure in which two stimuli of different intensity are presented, and the observer estimates the ratio of the perceived intensities.

method of residues

method of residues the fourth of the five canons of empirical science laid down by John Stuart Mill. It is meant to establish sufficient conditions for a phenomenon through the elimination of alternative potential causes on the basis of previous experiments or already known laws. For example, if the phenomena E1 and E2 occur together having antecedents C1 and C2, and if it is known by prior research or established law that C1 cannot cause E2 but causes E1, one may conclude that C2 is the cause of E2. Also called residue method.

method of right and wrong cases

method of right and wrong cases see method of constant stimuli.

method of selective adaptation

method of selective adaptation a psychophysical procedure in which repeated exposure to a stimulus produces sensory adaptation that influences perception of a subsequent stimulus.

method of serial exploration

method of serial exploration see method of just noticeable difference.

method of single stimuli

method of single stimuli any psychophysical procedure in which items in a series are presented one at a time, and the participant is required to respond to each in the absence of any comparison point or standard.

method of successive approximations

method of successive approximations a method of shaping operant behavior by reinforcing responses similar to the desired behavior. Initially, responses roughly approximating the desired behavior are reinforced. Later, only responses closely approximating the desired behavior are reinforced. The process gradually leads to the desired behavior. Also called successive-approximations method.

method of successive intervals

method of successive intervals a psychophysical procedure in which respondents place stimuli into categories defined by their diminishing degree of possession of an attribute. Thus, the first category would contain all stimuli judged to have the most of the attribute, the second category would contain those stimuli judged to have slightly less of the attribute, and so forth.

method of triads

method of triads any psychophysical procedure in which three stimuli are presented, and the observer must choose one of the three based on some property (e.g., its dissimilarity from the other two).

methodological behaviorism

methodological behaviorism a form of behaviorism that concedes the existence and reality of conscious events but contends that the only suitable means of studying them scientifically is via their expression in behavior. Compare radical behaviorism. See neobehaviorism.

methodological individualism

methodological individualism a theory that emphasizes the importance of each person in determining his or her own circumstances and minimizes any possible influence from larger societal groups or structures. For example, a researcher who endorsed methodological individualism would be less apt to consider how socioeconomic status might contribute to the level of achievement for a sample of individuals, preferring instead to investigate variables believed to be under each person’s control, such as motivation, determination, or ability.

methodological objectivism versus methodological subjectivism

methodological objectivism versus methodological subjectivism a prescriptive dimension along which psychological theories can be evaluated. Methodological objectivism is the position that methods of investigation can be, and should be able to be, repeated and verified by another investigator. Methodological subjectivism is the position that methods cannot be repeated and thus cannot be verified by another. See also contentual objectivism versus contentual subjectivism. [introduced by U.S. psychologist Robert I. Watson (1909–1980)]

methodological pluralism

methodological pluralism the belief that various approaches to conducting research, qualitative and quantitative, each have their respective strengths and weaknesses such that no one method is inherently superior to any other and no single method is best overall.

methodological solipsism

methodological solipsism the adoption of solipsism as a philosophical position because of the belief that no other position is tenable.

methodological triangulation

methodological triangulation the use of multiple quantitative and qualitative procedures to collect data so as to generate converging evidence on the topic of study. For example, a researcher studying alcohol consumption might employ methodological triangulation by measuring participants’ blood alcohol levels, collecting self-reports on quantity of alcohol consumed, and obtaining input from peers on quantity of alcohol consumed.

methodology

methodology n. 1. the science of method or orderly arrangement; specifically, the branch of logic concerned with the application of the principles of reasoning to scientific and philosophical inquiry. 2. the system of methods, principles, and rules of procedure used within a particular discipline. For example, in research and experimental design the term refers to the techniques used to collect information, and in statistics it refers to the procedures used to analyze such data.

methods analysis

methods analysis in ergonomics, the development of improved ways of performing a task, through analysis of the particular operation and its component tasks, techniques, factors, and resources. This typically involves use of process charts and micromotion studies and application of the principles of motion economy. See also task analysis.

methotrimeprazine

methotrimeprazine n. a low-potency antipsychotic of the aliphatic phenothiazine class. In the United States, it is currently used only for the treatment of pain. Also called levomepromazine. U.S. trade name: Levoprome.

methoxyhydroxyphenylglycol (MHPG)

Sorry, "methoxyhydroxyphenylglycol-mhpg" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

methyldopa

methyldopa n. a drug used for treating hypertension. It acts as an agonist at alpha-adrenergic receptors in brainstem centers that control the vascular system. When stimulated by methyldopa, these receptors, which act via an inhibitory feedback mechanism, slow the release of catecholamines from central neurons involved in the regulation of blood pressure. U.S. trade name: Aldomet.

methylphenidate

methylphenidate n. a stimulant related to the amphetamines and with a similar mechanism of action. It is an indirect agonist of catecholamine neurotransmission, blocking the reuptake of catecholamines from the synaptic cleft and stimulating presynaptic release of catecholamines. Unlike amphetamine, methylphenidate is more potent as a reuptake blocker than as a releasing agent. Methylphenidate is used as an adjunct to antidepressant therapy and to increase concentration and alertness in patients with brain injuries, brain cancer, or dementia. It is approved by the U.S. Food and Drug Administration for the treatment of attention-deficit/hyperactivity disorder (ADHD) and narcolepsy in both children and adults. In children with ADHD, methylphenidate increases attention and decreases impulsivity and physical overactivity, leading to improvement in academic and social functioning, at least while the drug is being administered. Potential long-term side effects include growth suppression, which may occur at least transiently in some children taking these drugs. It is not recommended to use methylphenidate or other stimulants in children without concurrent behavioral therapy or counseling. Methylphenidate has been used off-label by students and long-haul drivers to enhance attention and decrease fatigue. It is classified by the U.S. Drug Enforcement Administration as a Schedule II controlled substance (see scheduled drug). U.S. trade names (among others): Concerta; Metadate; Ritalin.

methylphenyl-tetrahydropyridine

methylphenyl-tetrahydropyridine n. see MPTP.

methylxanthine

methylxanthine n. any of a group of methylated derivatives of xanthines (stimulant plant alkaloids) with similar pharmacological actions. The most common are caffeine (1,3,7-trimethylxanthine), the active ingredient in coffee; theobromine (3,7-dimethylxanthine), the active ingredient in cocoa; and theophylline (1,3-dimethylxanthine), the active ingredient in tea. At low doses, methylxanthines cause CNS stimulation and arousal; at high doses, anxiety, agitation, and coma may result. Methylxanthines also relax bronchial muscles: Some (e.g., theophylline) have been used in the medical management of reactive airway disease, although they have now largely been supplanted by newer agents.

methysergide

methysergide n. an ergot derivative used in the treatment of migraine headaches. It reduces the frequency and intensity of migraine attacks in most individuals and is thought to act by opposing the action of serotonin (see serotonin antagonist). Methysergide is closely related to LSD and has similar effects at some tissue sites. Side effects of methysergide include light-headedness or dizziness, nausea or vomiting, euphoria, insomnia, and unsteadiness. U.S. trade name: Sansert.

metonymy

metonymy n. 1. a figure of speech in which not the literal word but one associated with it is used, as the sword for war. Synecdoche is the form of metonymy in which a whole is represented by a part or vice versa, as in referring to a laborer as a hand or a police officer as the police. 2. in speech pathology, a disturbance in which imprecise or inappropriate words and expressions are used. —metonymic adj.

Metrazol shock treatment

Metrazol shock treatment a form of shock therapy involving the intravenous injection of Metrazol, a trade name for pentylenetetrazol, a powerful CNS stimulant that induces convulsions and coma. Because the incidence of fatality from this procedure was high, it was discontinued in the 1940s. Also called Metrazol therapy; Metrazol treatment. [introduced in 1934 by Hungarian psychiatrist Ladislas von Meduna (1896–1964)]

metric

metric n. a scale or system used to express amount or quantity. For example, the Fahrenheit scale is a metric for assessing temperature and the system of IQ points is a metric for assessing intelligence.

metronomic pacing

metronomic pacing a technique of auditory feedback to improve speaking performance, in which a portable device containing an electronic metronome is typically set between 50 and 150 beats per minute and the speaker receives pacing feedback through headphones as he or she speaks. Among those who benefit most are stutterers and those with motor speech disorders.

Meyer’s loop

Meyer’s loop see optic radiations. [Adolf Meyer]

Meyer’s theory

Meyer’s theory the theory proposed by Adolf Meyer that mental disorders result from behavior patterns that develop as faulty responses to specific situations. He advocated a holistic approach (see psychobiology) to diagnosis and treatment of mental disorders.

Meynert’s nucleus

Meynert’s nucleus see basal nucleus of Meynert. [Theodor H. Meynert (1833–1892), Austrian neurologist]

MFF

MFF abbreviation for Matching Familiar Figures Test.

MHA

MHA abbreviation for Mental Health America.

MHC

MHC abbreviation for major histocompatibility complex.

MHPG

MHPG abbreviation for methoxyhydroxyphenylglycol.

MHV

MHV abbreviation for Mill Hill Vocabulary Scale.

mianserin

mianserin n. an antidepressant with a mechanism of action similar to that of the related compound mirtazapine. Mianserin is marketed in several countries (e.g., under the trade name Tolvon) but not in the United States.

Michelangelo phenomenon

Michelangelo phenomenon a process in which relationship partners support each other’s efforts toward achieving personally desired goals and particularly toward attaining an ideal self. Because committed partners must reconcile their personal goals with the needs and goals of their partners, partner encouragement or discouragement represents an important factor in how a person pursues a goal, as well as the likelihood of its attainment. [first identified in a 1999 article, “Close Partner as Sculptor of the Ideal Self,” by U.S. social psychologists Stephen M. Drigotas (1966– ), Caryl E. Rusbult (1952–2010), and colleagues; their coinage refers to the artist Michelangelo’s description of his sculptural work as releasing the beautiful form already present in a block of marble]

Michigan Alcoholism Screening Test (MAST)

Sorry, "michigan-alcoholism-screening-test-mast" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

Mickey Finn

Mickey Finn see knockout drops.

micro- (micr-)

Sorry, "micro-micr" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

microaggression

microaggression n. brief and commonplace verbal, behavioral, or situational indignities that communicate hostile, derogatory, or negative slights or insults, especially toward members of minority or oppressed groups. Microaggression may be intentional (e.g., calling a transgender person a “she-male”) or implicit (e.g., a White employee asking a Black colleague how he or she got a certain job, implying that the colleague may have obtained it through affirmative action or a quota system). Three subtypes have been identified: microassaults, which are purposefully discriminatory actions (e.g., uttering a racial slur, displaying a swastika); microinsults, which are subtle snubs that devalue a person’s identity; and microinvalidations, which are unintentional exclusions or negations of an individual’s thoughts, feelings, or experiences. Research on microaggression is limited but shows that this form of bias can cause recipients to feel that they are abnormal, inferior, invisible, powerless, or untrustworthy. [introduced in 1970 by U.S. psychiatrist Chester M. Pierce (1927– ); the subtypes were proposed in 2007 by U.S. psychologist Derald Wing Sue]

microcephaly

microcephaly n. a condition in which the circumference of the head is more than two standard deviations below the mean for age, gender, race, and gestation. It may be present at birth or develop in the first few years of life. The condition is associated with Down syndrome and other chromosomal syndromes; neurometabolic syndromes; maternal PKU; and prenatal exposure to drugs or alcohol, cytomegalovirus, rubella (German measles), varicella (chicken pox) virus, and certain toxic chemicals. Depending on the severity of their accompanying syndrome, children with microcephaly may have intellectual disability, delayed motor functions and speech, facial distortions, dwarfism or short stature, hyperactivity, seizures, difficulties with coordination and balance, and other brain or neurological abnormalities. Some children with microcephaly will have normal intelligence and a head that will grow bigger, although it will still be below the normal growth curves for head circumference. See also primary microcephaly. Compare macrocephaly. —microcephalic adj.

microcounseling

microcounseling n. a concentrated training approach originally designed to teach basic counseling skills to trainees in the helping professions (e.g., counseling, clinical psychology). Trainees apply specific, single skills (e.g., attending behavior, basic listening) in 5-minute videotaped sessions with volunteer clients, then view the video while receiving didactic instruction and feedback from a trainer, and then undergo a second round of videotaped skills application and subsequent review and instruction. The approach became a formal training program in the 1960s, founded on several principles, among them observational learning and rehearsal. It has since evolved to become a professional training paradigm for teaching techniques in specific types of therapies (e.g., cognitive behavior therapy, multicultural therapy), a conceptual framework for understanding the counseling process itself, and a method for teaching effective communication skills directly to clients (e.g., in conjoint therapy). Also called microteaching; microtraining. [developed by U.S. counseling psychologist Allen E. Ivey (1933– )]

microdata

microdata pl. n. 1. scores or other information collected on individual participants or units. In many research studies, microdata are consolidated into total scores, scale scores, or summary statistics known as aggregate data. 2. terms or codes used to elucidate the content of webpages, particularly ones based on hypertext markup language (HTML). Microdata help search engines identify webpage information relevant to the topic of interest and present it to users.

microdialysis

microdialysis n. a method for measuring the concentration of chemicals in a tissue or organ (e.g., a small region of brain) by allowing the chemicals to pass through a membrane into a small tube implanted in the interstitial space.

microelectrode

microelectrode n. an electrode with a tip no larger than a few micrometers in diameter that can be inserted into a single cell. In the microelectrode technique, used in studies of neurophysiology and disorders of the nervous system, intracellular microelectrodes with tips less than 1 μm in diameter are able to stimulate and record activity within a single neuron (single-cell or single-unit recording). Compare macroelectrode.

microergonomics

microergonomics n. an approach to ergonomics that focuses on the detailed examination of individual operator–machine interfaces or combinations. Compare macroergonomics.

microfilament

microfilament n. a very small protein filament (7 nm in diameter) found within all cells. Microfilaments are key components of the cell’s internal scaffolding (cytoskeleton) and help to determine cell shape.

microgenetic development

microgenetic development the series of changes that occur over relatively brief periods of time—in seconds, minutes, or days—as distinct from the larger scale changes that are conventionally studied in ontogenetic development (see ontogeny). [postulated by Lev Vygotsky in his sociocultural theory]

microgenetic method

microgenetic method a research methodology for studying cognitive developmental change, involving (a) observations of individual children throughout a period of change, (b) a high density of observations relative to the rate of change within that period, and (c) intensive trial-by-trial analyses intended to infer the processes that gave rise to the change. [developed by U.S. developmental psychologist Robert S. Siegler (1949– )]

microglia

microglia n. an extremely small type of nonneuronal central nervous system cell (glia) that removes cellular debris from injured or dead cells. —microglial adj.

microglossia

microglossia n. the condition of having an abnormally small tongue. Although relatively rare, the condition may occur during prenatal development and result in speech that sounds muffled.

micrographia

micrographia n. a disorder characterized by very small, often unreadable writing and associated most often with Parkinson’s disease.

micromastia

micromastia n. abnormally small breasts in a female.

micromelia

micromelia n. a birth defect marked by abnormal shortness or smallness of the limbs.

microorchidism

microorchidism n. abnormally small size of one or both testicles, as in Klinefelter’s syndrome. Also called microorchidia.

microphonia

microphonia n. see hypophonia.

micropolygyria

micropolygyria n. see lissencephaly.

micropsia

micropsia n. a visual illusion in which an object appears to be smaller than it is in reality. See also metamorphopsia. Compare macropsia.

micropsychosis

micropsychosis n. psychotic episodes of very brief duration (minutes to hours) that occur during times of stress. Micropsychoses have been observed primarily in borderline personality disorder and pseudoneurotic schizophrenia, although the latter is no longer a valid diagnostic entity.

microptic hallucination

microptic hallucination see Lilliputian hallucination.

microsaccades

microsaccades pl. n. small rapid eye movements that occur during attempted fixation of a target and cease when fixation is achieved.

microscopic level

microscopic level an investigative approach that focuses on the smallest recognizable units of analysis. Microscopic psychology is sometimes associated with physiological psychology at the cellular level.

microsleep

microsleep n. a momentary loss of awareness when a person is fatigued or sleep-deprived, especially during monotonous tasks, such as driving, looking at a computer, or passively monitoring machinery. Microsleep episodes may be noticed when the head literally drops forward and can last from less than 1 second to minutes. They are more likely to occur in the predawn and midafternoon hours and can be a major risk factor for traffic and industrial accidents.

microsmia

microsmia n. see hyposmia.

microsocial engineering

microsocial engineering a technique of conflict resolution among family members in which a behavior contract is established through a specific schedule of responsibilities, privileges, sanctions for violations, and bonuses for compliance.

microspectrophotometer

microspectrophotometer n. a device that enables the absorption of light across the spectrum to be measured as the light passes through a small sample. A microspectrophotometer is used to determine the absorption spectrum of photopigments in retinal rods and cones.

microsplanchnic type

microsplanchnic type a constitutional type characterized by a small abdomen and an elongated body. Also called microsplanchnic build. [described by Italian physician Giacinto Viola (1870–1943)]

microsystem

microsystem n. see mesosystem.

microtome

microtome n. a device for cutting thin sections (slices) of tissue, used, for example, in preparing brain sections for microscopic examination. Compare cryostat.

microtraining

microtraining n. see microcounseling.

microtubule

microtubule n. a small, hollow, cylindrical structure (typically 20 nm–26 nm in diameter), numbers of which occur in various types of cell. Microtubules are part of the cell’s internal scaffolding (cytoskeleton) and form the spindle during cell division. In neurons, microtubules are involved in axonal transport.

microvillus

microvillus n. (pl. microvilli) a slender, minute structure projecting from the surface of a cell. For example, in taste perception, a microvillus is the hairlike extension of each taste cell that projects through the pore of a taste bud to sample the environment. Although a microvillus accounts for only 3% of the surface area of a taste cell, it is studded with receptor proteins that recognize specific molecules and is the site of taste transduction.

micturition

micturition n. see urination. —micturate vb.

micturition reflex

micturition reflex reflex contraction of the bladder in response to signals from its stretch receptors. During development, a child learns to suppress the micturition reflex and to control urination. Also called bladder reflex.

midazolam

midazolam n. a highly potent, short-acting benzodiazepine used chiefly for the induction of anesthesia or conscious sedation for operative procedures. It is available in a form for intravenous or intramuscular administration and as a syrup for oral administration. Because of its potential to induce respiratory depression (particularly when used as a sedating agent in nonsurgical situations), its short half-life, and the need for continuous monitoring of respiratory and cardiac function, midazolam has little, if any, application in mental health settings. It has reportedly been used as a date-rape drug. U.S. trade name: Versed.

midbrain

midbrain n. a relatively small region of the upper brainstem that connects the forebrain and hindbrain. It contains the tectum (and associated inferior and superior colliculi), tegmentum, and substantia nigra. Also called mesencephalon.

middle cerebral artery

middle cerebral artery the largest branch of the internal carotid artery, running first through the lateral sulcus and then upward on the surface of the insula. Here it divides into several branches, including the anterior choroidal artery, which spread over the lateral surface of the cerebral hemispheres.

middle class

middle class a general socioeconomic class in the middle of a social hierarchy. In economic terms, it is sometimes held to consist of an upper middle class of professionals, administrators, and middle-level executives and a lower middle class of shopkeepers, artisans, clerical staff, and service workers. The latter, although still relatively materially privileged, are often not positioned as advantageously in the power structure of a society. Also called bourgeoisie. See social class; socioeconomic status.

middle cranial fossa

middle cranial fossa see fossa.

middle ear

middle ear a membrane-lined cavity in the temporal bone of the skull. It is filled with air and communicates with the nasopharynx through the eustachian tube. It contains the ossicles, which transmit sound vibrations from the outer ear and the tympanic membrane (eardrum) to the oval window of the inner ear. Also called tympanic cavity.

middle insomnia

middle insomnia a period of sleeplessness that occurs after falling asleep normally, with difficulty in falling asleep again. It is a common symptom of a major depressive disorder. Also called broken sleep. Compare initial insomnia; terminal insomnia. See also segmented sleep.

middle knowledge

middle knowledge a cognitive state in which terminally ill people acknowledge yet cannot completely comprehend their mortal danger. Selective attention, denial, resistance, or some other protective strategy tends to be used more or less intensively depending on many factors, including physical condition, security within close relationships, and the ability to integrate the prospect of death into the overall evaluation of one’s life. [introduced by U.S. psychiatrist Avery D. Weisman]

middle temporal gyrus (MTG)

Sorry, "middle-temporal-gyrus-mtg" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

middle-child syndrome

middle-child syndrome a hypothetical condition purported to be shared by all middle-born children, based on the assumption that middle children in a family develop personality characteristics that are different from first-born and later born children. Current research indicates that a child’s birth order in a particular family may have small, subtle influences on personality and intelligence but not strong and consistent effects on psychological outcomes. See also birth order.

midget

midget n. see dwarfism.

midget bipolar cell

midget bipolar cell a retinal bipolar cell that connects to only one retinal cone. Compare diffuse bipolar cell.

midlife crisis

midlife crisis a period of psychological distress thought to occur in some individuals during the middle years of adulthood, roughly from ages 35 to 65. Causes may include significant life events and health or occupational problems and concerns. However, no empirical data exist to support the notion that this distress is specific to midlife, and many researchers consider the midlife crisis a myth. See also age crisis. [coined in 1965 by Canadian consulting organizational psychologist Elliot Jaques (1917–2003)]

midline

midline n. a bisecting or median line, especially in reference to an imaginary median line or plane through the body or a part of the body.

midparent

midparent adj. describing an average measure of both parents with regard to height, intelligence, or other characteristics.

midpoint

midpoint n. see median.

midrange

midrange n. the average of the lowest and highest scores in a set of data. The midrange is a measure of central tendency more prone to bias than the mean, median, and mode because it relies solely upon the two most extreme scores, which potentially are outliers. For example, consider the following hours per week spent using a computer for five individuals: 6, 10, 15, 21, and 35. The midrange is 20.5, the mean is 17.4, and the median is 15. The midrange score thus is larger than the mean or median due to the influence of the outlier of 35 hours.

midspread

midspread n. see interquartile range.

midwife

midwife n. a professionally trained and licensed health care provider of primary medical services for women, including perinatal (prenatal, delivery, and postpartum) care for pregnant women and new mothers and most family planning and gynecological services for healthy women of all ages. Midwives work together with obstetrics and gynecology (OB/GYN) doctors. They either consult with or refer to other health care providers in cases that are outside of their expertise (e.g., high-risk pregnancies, pregnant women with a chronic illness). Compare doula. —midwifery n.

Mignon delusion

Mignon delusion a variation of the family-romance fantasy in which children believe that their parents are actually foster parents and their real families are of distinguished lineage. The name is derived from the child character in the novel Wilhelm Meister’s Apprenticeship (1796) by Johann Wolfgang von Goethe (1749–1832).

migraine headache

migraine headache a headache that is recurrent, usually severe, usually limited to one side of the head, and likely to be accompanied by nausea, vomiting, and photophobia. Migraine headaches may be preceded by an aura of flickering or flashing light, blacking out of part of the visual field, or illusions of colors or patterns. They are much more common in women than in men. Also called sick headache.

Migranal

Migranal n. a trade name for dihydroergotamine.

migration

migration n. 1. travel by nonhuman animals over relatively long distances to or from breeding areas. Migration is observed in birds, fish, and some mammals and insects (among others). In some species, it is seasonal, involving movement from a breeding area to an overwintering area; in others, particularly the salmon, it is observed only once in the lifetime of an individual. Factors influencing migratory behavior include chemical cues, pituitary or other hormones, relative change in day length, and temperature. See also migratory restlessness; navigation. 2. in the development of the nervous system, the movement of nerve cells from their origin in the ventricular zone to establish distinctive cell populations, such as brain nuclei and layers of the cerebral cortex.

migratory restlessness

migratory restlessness increased activity that occurs prior to the period of migration. Migratory restlessness in captive animals is an index of responsiveness to cues indicating annual cycles. Also called Zugunruhe.

MIH

MIH abbreviation for Müllerian-inhibiting hormone.

mild cognitive impairment (MCI)

Sorry, "mild-cognitive-impairment-mci" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mild mental retardation

mild mental retardation an older diagnostic and classification category applying to those with IQs of 50 to 69, comprising 85% of people with mental retardation. These individuals usually develop good communication skills and reach a sixth-grade level of academic performance in their late teens, but they may not develop beyond the social skill levels typical of adolescents. Usually, they are able to learn life and vocational skills adequate for basic self-support and independent living.

milieu

milieu n. (pl. milieux) 1. the environment in general. 2. in psychology and psychiatry, the social environment, especially the atmosphere and character of the home, neighborhood, school, workplace, and so on as they affect the personality and adjustment of the individual.

milieu therapy

milieu therapy psychotherapeutic treatment based on modification or manipulation of the client’s life circumstances or immediate environment. Milieu therapy attempts to organize the social and physical setting in which the client lives or is being treated in such a way as to promote healthier, more adaptive cognitions, emotions, and behavior. See also environmental therapy; therapeutic community.

military environment

military environment factors that affect human performance in military operations. Performance may be compromised by exposure to extreme weather conditions (ranging from excessive heat to extreme cold); other factors include the effects of clothing and equipment in different environments, motivational and attitudinal factors, acclimatization, the size of the unit involved, and the quality of its leadership.

military officer selection

military officer selection the selection and assessment of military personnel considered suitable to carry the special responsibilities associated with being an officer. The assessment techniques used by applied psychologists involve evaluation of an individual’s academic qualifications, use of psychological instruments in recognized assessment centers, and construct-oriented psychological assessment.

military peacekeeping

military peacekeeping military operations that, with the consent of the belligerent parties in a conflict, are conducted to maintain a negotiated truce and to facilitate a diplomatic resolution. Peacekeeping operations may include withdrawal and disengagement, ceasefire, prisoner-of-war exchanges, arms control, demilitarization, and demobilization. Military peacekeeping is frequently carried out on a multinational basis.

Military Personnel Management

Military Personnel Management a strategic global framework proposed by the U.S. Department of Defense for achieving an accurate accounting of deployed personnel. It concentrates on identifying and eliminating waste, avoiding duplication, and reducing costs in military establishments.

military psychology

military psychology the application of psychological principles, theories, and methods to the evaluation, selection, assignment, and training of military personnel, as well as to the design of military equipment. This field of applied psychology also includes the application of clinical and counseling techniques to the maintenance of morale and mental health in military settings and covers human functioning in a variety of environments during times of peace and war.

military stress factors

military stress factors circumstances that potentially affect the number of military personnel that become stress casualties, including the nature of the operation in which they are involved; the intensity of the conflict, the number of battle casualties occurring, and the size, cohesion, and leadership of the unit in which they are serving.

Military Testing Association

Military Testing Association see International Military Testing Association.

milk letdown reflex

milk letdown reflex in mothers who are nursing, an automatic release of milk from sacs within the mammary glands in response to infant suckling or associated stimuli (e.g., the infant’s cry). The milk letdown reflex is regulated by the hormone oxytocin: Suckling stimulates the production of oxytocin, which in turn stimulates contractions of the smooth muscle myoepithelial cells surrounding the mammary glands, leading to the expulsion of milk from the sacs into ducts that converge on the nipples. The actual production of milk by the mammary glands is regulated by the hormone prolactin. Also called milk ejection reflex.

Mill Hill Vocabulary Scale (MHV)

Sorry, "mill-hill-vocabulary-scale-mhv" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

Mill’s canons

Mill’s canons a set of five principles of sound experimental science proposed by John Stuart Mill. These principles outline the logical conditions under which observations can establish necessary and sufficient causal relationships between events. Because each of the principles enables the observer to eliminate potential causes, the general approach is often referred to as eliminative induction. Mill’s work in this area is related to both the method of exclusion described by Francis Bacon and the work on the logic of causality of David Hume. It also presages the falsificationism of Austrian-born British philosopher Karl Popper (1902–1994). Mill’s five canons are (a) the method of agreement, (b) the method of difference, (c) the method of agreement and difference, (d) the method of residues, and (e) the method of concomitant variation.

millenarianism

millenarianism n. 1. belief in the imminent end of human history, to be followed by a thousand-year period of peace and blessedness (often associated with the Second Coming of Christ). Such beliefs were current in the early Christian church and appeared sporadically, primarily from the 11th through the 17th centuries, in periods of political or intellectual crisis and among marginalized groups. Some groups proclaim similar beliefs but without the language and imagery of Christianity. 2. by extension, any belief that rapid and violent change can lead to a golden age of justice and peace. —millenarian adj.

Miller Analogies Test (MAT)

Sorry, "miller-analogies-test-mat" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

Miller–Mowrer shuttle box

Miller–Mowrer shuttle box an apparatus for studying escape and avoidance learning. It consists of a straight alley with a guillotine door at its midpoint and a grid floor that can be electrified independently in each half. The experimental animal can avoid the aversive stimulus (an electric shock) by moving to the opposite end of the box but must do so within a given time. [Neal E. Miller and O. Hobart Mowrer]

milling crowd

milling crowd an aggregation of individuals, usually gathered in a public area (e.g., a street or concourse), whose members seem to be moving restlessly or aimlessly about the area.

Millon Clinical Multiaxial Inventory (MCMI)

Sorry, "millon-clinical-multiaxial-inventory-mcmi" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

Miltown

Miltown n. a trade name for meprobamate.

mimetic

mimetic adj. relating to imitation, as in a young chimpanzee’s imitation of its parent’s actions or a parrot imitating the words of its owner. A mimetic response is a copying or imitative response. Mimetic can also refer to physical features, such as the pseudopenis of the female spotted hyena, which is an enlargement of the clitoris and vagina through which mating and birth are accomplished. —mimesis n.

mimicry

mimicry n. 1. the presence of physical or behavioral traits in one species that so closely resemble those of another species that they confuse observers. This resemblance makes it possible for an organism either to evade predators (see Batesian mimicry; Müllerian mimicry) or to attract prey (see aggressive mimicry). 2. a form of social learning in which people, without conscious awareness or intent, automatically copy other people’s physical movements (behaviors such as postures, gestures, and mannerisms), facial expressions, speech patterns, and emotions during interpersonal interactions. It is thought that the behavioral form in particular, called behavioral mimicry, arises out of the need to affiliate and facilitates an effort to establish rapport with others. See also emulation; imitation; local enhancement.

min strategy

min strategy an arithmetic strategy in which children faced with an addition problem start with the largest addend and count up from there. For example, for the problem, 3 + 2 = ?, a child would say “3… 4, 5.”

mind

mind n. 1. broadly, all intellectual and psychological phenomena of an organism, encompassing motivational, affective, behavioral, perceptual, and cognitive systems; that is, the organized totality of an organism’s mental and psychic processes and the structural and functional cognitive components on which they depend. The term, however, is also used more narrowly to denote only cognitive activities and functions, such as perceiving, attending, thinking, problem solving, language, learning, and memory. The nature of the relationship between the mind and the body, including the brain and its mechanisms or activities, has been, and continues to be, the subject of much debate. See mind–body problem; philosophy of mind. 2. the substantive content of such mental and psychic processes. 3. consciousness or awareness, particularly as specific to an individual. 4. a set of emergent properties automatically derived from a brain that has achieved sufficient biological sophistication. In this sense, the mind is considered more the province of humans and of human consciousness than of organisms in general. 5. human consciousness regarded as an immaterial entity distinct from the brain. See Cartesian dualism; ghost in the machine. 6. the brain itself and its activities. In this view, the mind essentially is both the anatomical organ and what it does. 7. intention or volition. 8. opinion or point of view. 9. the characteristic mode of thinking of a group, such as the criminal mind or the military mind.

mind control

mind control 1. an extreme form of social influence used to indoctrinate an individual in the attitudes and beliefs of a group, usually one that is religious or political in nature. See brainwashing; coercive persuasion. 2. the control of physical activities of the body, particularly autonomic functions, by mental processes. See autogenic training; biofeedback. See also mind–body intervention.

mind reading

mind reading a form of alleged extrasensory perception in which an individual claims to have access to the thoughts of another person. With thought transference, it is one of the two main forms of telepathy.

mind stuff

mind stuff in the philosophy of British mathematician William K. Clifford (1845–1879), the single substance that constitutes reality; this consists internally of mind but appears externally in the form of matter. His argument, from evolution, was that since consciousness exists in humankind, and humankind evolved from matter, matter must also possess consciousness. Clifford’s position is often taken to be one of panpsychism.

mind wandering

mind wandering a condition in which thoughts do not remain focused on the task at hand but range widely and spontaneously across other topics. It tends to occur during tasks that do not require sustained attention. Mind wandering cannot be scientifically quantified but has been studied using thought sampling and questionnaires. Research questions include how much mind wandering is a stable personality trait, how much it is linked to mood and situation, and how it relates to processing capacity and working memory. The contents of mind wandering are often referred to as task-unrelated thoughts (TUTs), task-unrelated images and thoughts (TUITs), or stimulus-independent and task-unrelated thoughts (SITUTs). See also absent-mindedness; intrusive thoughts.

mind-set

mind-set n. a state of mind that influences how people think about and then enact their goal-directed activities in ways that may systematically promote or interfere with optimal functioning. German psychologist Peter Gollwitzer (1950– ) identified two types: (a) a deliberative mind-set, in which a person debates the merits and drawbacks of various courses of action (or inaction) when choosing a goal to pursue from a set of possible goals; and (b) an implemental mind-set, in which a person has made the choice and execution of particular actions to realize chosen goals. Mind-sets sometimes generalize from one activity to later, unrelated activities.

mind–body intervention

mind–body intervention therapeutic approaches that focus on harnessing the power of the mind to bring about change in the body or achieve reduction of symptoms of disease or disorder. The various techniques used include relaxation training (e.g., autogenic training, progressive relaxation), meditation, prayer, and creative arts therapy. See also complementary and alternative medicine.

mind–body problem

mind–body problem the problem of accounting for and describing the relationship between mental and physical processes (psyche and soma). Solutions to this problem fall into six broad categories: (a) interactionism, in which mind and body are separate processes that nevertheless exert mutual influence (see Cartesian dualism); (b) parallelism, in which mind and body are separate processes with a point-to-point correspondence but no causal connection (see occasionalism; preestablished harmony); (c) idealism, in which only mind exists and the soma is a function of the psyche; (d) double-aspect theory, in which body and mind are both functions of a common entity (see neutral monism); (e) epiphenomenalism, in which mind is a by-product of bodily processes; and (f) materialism, in which body is the only reality and the psyche is nonexistent. Categories (a) and (b) are varieties of dualism; the remainder are varieties of monism. In the context of psychopathology, two central questions arising from the mind–body problem are which sphere takes precedence in the genesis and development of illness and how does each sphere affect the other. Also called body–mind problem.

mind–brain–education (MBE)

Sorry, "mind-brain-education-mbe" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mind’s eye

mind’s eye the mind’s capacity to recall or create images based on visual experience. See visual imagery.

mindblindness

mindblindness n. 1. a deficit in theory of mind that is characteristic of people with autism. A person with mindblindness cannot “read the minds” of others—that is, understand their behavior in terms of belief–desire reasoning. [described by British psychologist Simon Baron-Cohen (1958– )] 2. an obsolete name for visual agnosia. [coined in 1881 by Polish-born German physiologist Hermann Munk]

mindfulness

mindfulness n. awareness of one’s internal states and surroundings. The concept has been applied to various therapeutic interventions—for example, mindfulness-based cognitive behavior therapy, mindfulness-based stress reduction, and mindfulness meditation—to help people avoid destructive or automatic habits and responses by learning to observe their thoughts, emotions, and other present-moment experiences without judging or reacting to them. —mindful adj.

mindfulness meditation

mindfulness meditation a type of meditation in which a person focuses attention on his or her breathing and thoughts, feelings, and sensations are experienced freely as they arise. Mindfulness meditation is intended to enable individuals to become highly attentive to sensory information and to focus on each moment as it occurs. See also transcendental meditation. Compare concentrative meditation.

mindsight

mindsight n. a proposed but controversial mode of nonconscious or semiconscious vision that may permit visual decision making in the absence of fully conscious visual perception. Research on mindsight has arisen out of work on change blindness. [proposed by Canadian psychologist and computer scientist Ronald A. Rensink]

mineralocorticoid

mineralocorticoid n. any corticosteroid hormone that affects ion concentrations in body tissues and helps to regulate the excretion of salt and water. In humans, the principal mineralocorticoid is aldosterone.

MINERVA 2

MINERVA 2 a global memory model that describes, in mathematical form, memory for both individual experiences (see episodic memory) and abstract generic facts (see semantic memory). The model postulates that each experience leaves a memory trace, and repetition creates multiple copies rather than strengthening a single trace. Memory retrieval activates the sum of all relevant traces. [proposed by Douglas L. Hintzman (1941– )]

Mini-Mental State Examination (MMSE)

Sorry, "mini-mental-state-examination-mmse" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

miniature end-plate potential

miniature end-plate potential see end plate.

miniature system

miniature system the organized, integrated knowledge, including facts, assumptions, and theories or hypotheses, relating to a restricted area of study. An example is the theory that explains a particular perceptual phenomenon, such as the Müller-Lyer illusion.

minimal audible field (MAF)

Sorry, "minimal-audible-field-maf" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

minimal audible pressure (MAP)

Sorry, "minimal-audible-pressure-map" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

minimal brain dysfunction (MBD)

Sorry, "minimal-brain-dysfunction-mbd" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

minimal group

minimal group 1. a group lacking interdependence, group cohesion, structure, and other characteristics typically found in social groups. An example is a group of people disembarking from a bus. 2. a type of zero-history nominal group assembled and studied in the minimal intergroup situation. It has been found that individuals in such groups respond in biased ways when allocating resources to ingroup and outgroup members, even though the groups are not psychologically or interpersonally meaningful. [introduced by Polish-born British social psychologist Henri Tajfel (1919–1982)]

minimal intergroup situation

minimal intergroup situation 1. any situation involving contact between two or more minimal groups, as when a group of individuals disembarking from a bus mingles with a group of individuals getting on the bus. 2. a research procedure, used mainly in studies of intergroup conflict, that involves creating temporary groupings of anonymous people whose interdependence is virtually nil. Also called minimal group paradigm. [developed by Polish-born British social psychologist Henri Tajfel (1919–1982)]

minimal pair

minimal pair in linguistics, two forms that differ in just one phonological feature, thereby illustrating the critical contrastive role played by that feature. In English, for example, the spoken forms [pin] and [bin] are a minimal pair that serve to identify /p/ and /b/ as distinct phonemes. See binary feature; emic–etic distinction.

minimally conscious state (MCS)

Sorry, "minimally-conscious-state-mcs" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

minimax strategy

minimax strategy in game theory or decision making, a tactic in which individuals attempt either to minimize their own maximum losses or to reduce the most an opponent will gain. For example, a health researcher may propose an intervention that would be the least aversive treatment for a serious disease, thereby minimizing the adverse effects patients may expect to experience as a result of the disease. Compare maximin strategy.

minimization

minimization n. cognitive distortion consisting of a tendency to present events to oneself or others as insignificant or unimportant. Minimization often involves being unclear or nonspecific, so the listener does not have a complete picture of all the details and may be led to draw inaccurate or incomplete conclusions.

minimum power theory

minimum power theory an analysis of coalition formation processes that assumes that (a) all members who control sufficient resources to turn a winning coalition into a losing one or a losing coalition into a winning one are equal in terms of power; and (b) individuals’ expectations concerning the division of the coalition’s payoff will conform to an equity norm (see equity theory), but one based on power rather than resources. This theory predicts that the most likely coalition to form in a group will be one that wins but comprises the individuals with the smallest amounts of power consistent with this outcome. Compare minimum resource theory.

minimum resource theory

minimum resource theory an analysis of coalition formation processes that assumes that (a) people in group situations will behave hedonistically and thus will be motivated to maximize their power, outcomes, and payoffs by forming coalitions; and (b) individuals’ expectations concerning the division of the coalition’s payoff will conform to an equity norm (see equity theory). The minimum resource theory predicts that the most likely coalition to form in a group will be the one that contains those individuals whose total, combined resources are the fewest needed to control the outcome of the entire group. Compare minimum power theory.

minimum separable

minimum separable the minimum distance that can be detected between two adjacent high-contrast visual stimuli. This distance, 1 minute of arc at the fovea, is about 60 times greater than the minimum detectable width of a line that appears alone. Compare minimum visible.

minimum visible

minimum visible the narrowest visual stimulus that can be detected when it appears alone in the visual field. Compare minimum separable.

Minnesota Multiphasic Personality Inventory (MMPI)

Sorry, "minnesota-multiphasic-personality-inventory-mmpi" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

Minnesota Satisfaction Questionnaire (MSQ)

Sorry, "minnesota-satisfaction-questionnaire-msq" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

minor

minor n. a person who is not legally an adult. See also emancipated minor.

minor depression

minor depression see dysthymia.

minor depressive disorder

minor depressive disorder in an appendix to DSM–IV–TR, a proposed diagnosis of a mood disorder in which an individual experiences persistent sadness or anhedonia and other symptoms similar to major depressive disorder or dysthymic disorder but without meeting the full criteria for either diagnosis. These other symptoms may include appetite, weight, or sleep changes; psychomotor agitation or psychomotor retardation; fatigue or loss of energy; feelings of worthlessness or guilt; difficulty concentrating or making decisions; and recurrent thoughts of death or suicide.

minor tranquilizer

minor tranquilizer see anxiolytic.

minority group

minority group a population subgroup with social, religious, ethnic, racial, or other characteristics that differ from those of the majority of the population. The term is sometimes extended to cover any group that is the subject of oppression and discrimination, whether or not it literally comprises a minority of the population. When members of groups historically considered minorities make up more than 50% of an area’s population, that jurisdiction is described as majority-minority. See also ethnic group; subculture.

minority influence

minority influence social pressure exerted on the majority of a group by a smaller faction of the group. Studies suggest that minorities who argue consistently prompt the group to reconsider even long-held or previously unquestioned assumptions and procedures. Majority influence tends to be direct and results in conformity, but minority influence is indirect and instigates innovation and conversion, as the members of the majority struggle to validate their judgments.

minority stress

minority stress the physiological and psychological effects associated with the adverse social conditions experienced by ethnic and racial minorities, lesbians, gay men, bisexual and transgender individuals, and others who are members of stigmatized social groups. Common sources of minority stress include experiencing prejudice, discrimination, harassment, or verbal or physical violence; expecting or experiencing rejection by others; concealing one’s minority identity; and internalizing negative societal attitudes about one’s social group that results in a negative self-view. The concept frequently is invoked by researchers to explain the increased rates of depression, suicide, anxiety, substance abuse, workplace problems, body image problems, eating disorders, high blood pressure, cardiovascular disease, and other mental and physical conditions among members of minority or marginalized groups. Conversely, researchers have hypothesized certain protective factors that help ameliorate the adverse health outcomes of minority stress. These include personal characteristics, such as resilience and an effective coping strategy, and social support mechanisms, such as group solidarity, group cohesion, and collective self-esteem. [coined in 1995 by Israeli-born U.S. social psychologist Ilan H. Meyer]

minty

minty adj. denoting one of the seven classes of odorants in the stereochemical smell theory.

miosis (myosis)

Sorry, "miosis-myosis" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

Miranda warning

Miranda warning a warning given in the United States by police officers to suspects during an arrest to make them aware of their rights against self-incrimination. Suspects must be told they have the right to remain silent and the right to have an attorney present during questioning; an attorney will be provided if suspects cannot afford one. They must also be informed that anything they say can be used as evidence against them in court. It is named for the defendant in Miranda v. Arizona, a case that was ultimately decided in 1966 by the U.S. Supreme Court. Also called Miranda rights.

mirror drawing

mirror drawing a motor-skill test of the ability to alter well-learned patterns of hand–eye coordination. In the test, the participant traces an image while looking into a mirror that shows only the image and the pencil.

mirror imaging

mirror imaging 1. a type of reversed asymmetry of characteristics often found between twins, particularly monozygotic twins. Examples include handedness, fingerprints, and hair whorls. 2. see mirror neuron.

mirror neuron

mirror neuron a type of cell in the brains of certain animals (including humans) that responds in the same way to a given action (e.g., grasping an object) whether the animal performs the action itself or sees another animal (not necessarily of the same species) perform the action. This phenomenon is known as mirror imaging. [named and described by 21st-century Russian-born Italian neurologist Giacomo Rizzolati]

mirror phase

mirror phase the stage in development occurring around 6 to 18 months of age when the infant becomes able to imagine himself or herself as an autonomous ego in the image of the parent and also starts to recognize his or her reflection in a mirror. That is, the child begins to acquire a self-image. French psychoanalyst Jacques Lacan (1901–1981), who introduced the phrase, saw this as marking the start of the infant’s transition from the realm of the Imaginary to that of the Symbolic. See also name-of-the-father.

mirror reading

mirror reading 1. reading in a pattern that is the reverse of that generally followed. 2. a task in which a person must read words that are presented one at a time in mirror image. 3. a preference for reading mirror-reversed rather than normally written words.

mirror sign

mirror sign 1. the tendency to look at oneself in a reflecting surface (window, mirror, etc.) frequently and for an extended period of time. [first described in 1927 by French psychologist Paul Abely as an early symptom of schizophrenia] 2. the inability to recognize the reflection of oneself in a mirror, described mainly in moderate or severe dementia, especially Alzheimer’s disease.

mirror technique

mirror technique 1. the conscious use of active listening by the therapist in psychotherapy, accompanied by reflection of the client’s affect and body language in order to stimulate a sense of empathy and to further the development of the therapeutic alliance. 2. in psychodrama, a technique in which an auxiliary ego imitates a client’s behavior patterns to show that person how others perceive and react to him or her. Also called mirroring.

mirror transference

mirror transference in self psychology, a narcissistic transference technique in which patients’ grandiose selves are reactivated as a replica of the early phase of their lives when their mothers established or undermined their sense of perfection by admiring or devaluing their exhibitionistic behavior. This “reactivation process” aims to help the patient develop healthy self-esteem. Compare idealizing transference; twinship transference. [first described by Austrian-born U.S. psychoanalyst Heinz Kohut (1913–1981)]

mirror writing

mirror writing the production of individual letters and whole word strings in reverse direction. Mirror writing is characterized by an inversion of letters and words such that they appear reversed unless viewed in a mirror. It is related to strephosymbolia.

mirror-box technique

mirror-box technique a rehabilitation method in which an individual who has lost the use of a limb due to stroke places both affected and unaffected limbs (e.g., left arm and right arm) into slots of a box containing two mirrors in the center that each face outward, reflecting the respective limb. The person moves the intact limb and watches its reflection in the corresponding mirror, which gives the illusion that the other, paralyzed limb is moving in response to the brain’s commands. Research has shown that the technique aids recovery of limb function following stroke, perhaps by tapping into former mirror neuron circuits that have only been partially damaged. The technique also is used, in modified form, with individuals who have lost a limb to amputation and has been effective in reducing or alleviating their phantom limb pain. [developed by neurologist Vilayanur S. Ramachandran (1951– )]

mirror–touch synesthesia

mirror–touch synesthesia see synesthesia.

mirroring

mirroring n. 1. reflecting or emulating speech, affect, behavior, or other qualities in psychotherapeutic contexts. A therapist may adopt the movements, speech style, or locutions of a client, and vice versa, to indicate comprehension of what is being said or to reflect bonding, either nonconsciously or with the intent of empathizing. 2. the positive responses of parents to a child that are intended to instill internal self-respect. 3. see mirror technique.

mirtazapine

mirtazapine n. an antidepressant whose mechanism of action differs from that of most other antidepressants. It is considered to be a multifunctional antidepressant in that two separate actions result in increased neurotransmission of norepinephrine and serotonin. By binding to presynaptic α2-adrenoreceptors (see alpha-adrenergic receptor; autoreceptor), it enables continued release of norepinephrine from presynaptic neurons. It also acts as a serotonin agonist at postsynaptic 5-HT1 receptors. Other actions of mirtazapine include potent antagonism of other serotonin and histamine receptors, but it does not inhibit the reuptake of serotonin or norepinephrine. Sedation and weight gain are common adverse effects of mirtazapine, probably due to its potent ability to block the histamine H1 receptor. Unlike many other antidepressants, in most patients mirtazapine does not cause sexual dysfunction. Rarely, agranulocytosis has been associated with its use. U.S. trade name: Remeron.

MIS

MIS 1. abbreviation for Müllerian-inhibiting substance. See Müllerian-inhibiting hormone. 2. abbreviation for management information systems.

mis-

MIS 1. abbreviation for Müllerian-inhibiting substance. See Müllerian-inhibiting hormone. 2. abbreviation for management information systems.

misandry

misandry n. hatred or contempt for men. Compare misogyny. —misandrist n., adj.

misanthropy

misanthropy n. a hatred, aversion, or distrust of human beings and human nature. —misanthrope n. —misanthropic adj.

misarticulation

misarticulation n. 1. faulty articulation, resulting in unclear, imprecise speech sounds and poorly understood speech. 2. a poorly articulated sound or utterance.

misattribution

misattribution n. an incorrect inference as to the cause of an individual’s or group’s behavior or of an interpersonal event. For example, misattribution of arousal is an effect in which the physiological stimulation generated by one stimulus is mistakenly ascribed to another source. See also attribution theory.

misattunement

misattunement n. 1. a lack of rapport between infant and parent or caregiver such that the infant’s efforts at communication and expression are not responded to in a way that allows the infant to feel understood. 2. in psychoanalysis, a lack of empathy by a therapist or analyst toward a patient. Compare attunement; empathic failure.

miscarriage

miscarriage n. see abortion.

miscegenation

miscegenation n. marriage, sexual activity, or reproduction among individuals of different racial or ethnic groups, especially when this is emphasized by marked physical differences (e.g., skin color). The term has traditionally carried a heavy sense of disapproval and is now largely archaic and disfavored. See also exogamy; intermarriage; outbreeding. —miscegenational adj.

misclassification cost

misclassification cost an estimate of the costs that could arise from assigning an incorrect category or status to a situation or condition. For example, it would be worthwhile to estimate the misclassification cost of prematurely telling the public that previously contaminated town water is now safe to drink, versus waiting longer than needed to let people know they can drink the water. In this case, the misclassification cost of an early announcement would be much more serious—possibly involving severe illness or even loss of life—than that of a later announcement.

misdiagnosis

misdiagnosis n. an incorrect, inaccurate, or incomplete identification of a disease or disorder.

miseducation

miseducation n. teaching information, intentionally or in good faith, that is incorrect. The teaching of history is a common example of this, as historical material is prone to subjectivity, depending on the point of view of the writer and the period during which it was written.

misidentification

misidentification n. failure to identify individuals correctly due to impaired memory or a confused state, as in dementia or alcoholic intoxication or sometimes in mania.

misidentification syndrome

misidentification syndrome a disorder characterized by the delusional misidentification of oneself, other people, places, or objects. The misidentification may be expressed as the mistaken belief that a person has altered his or her identity in some way, either physically or psychologically, or that some place or object has undergone transformation. Also called delusional misidentification syndrome. See also Capgras syndrome; Fregoli’s phenomenon; intermetamorphosis syndrome.

misinformation effect

misinformation effect a phenomenon in which a person mistakenly recalls misleading information that an experimenter has provided, instead of accurately recalling the correct information that had been presented earlier. The misinformation effect is studied in the context of eyewitness memory.

miso- (mis-)

Sorry, "miso-mis" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

misocainia (misocainea)

Sorry, "misocainia-misocainea" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

misogamy

misogamy n. hatred of or aversion to marriage. —misogamist n.

misogyny

misogyny n. hatred or contempt for women. Compare misandry. —misogynist n. —misogynistic adj.

misologia

misologia n. an aversion to speaking or arguing. Also called misology.

misoneism

misoneism n. an extreme resistance to change and intolerance of anything new, sometimes expressed as an obsessive desire to maintain routines and preserve the status quo. It is often associated with autism. Also called misocainia. —misoneist n.

misopedia

misopedia n. a hatred of children. Also called misopedy.

misorientation effect

misorientation effect difficulty recognizing an object when it appears in an orientation different from that in which it was initially learned. The effect is critical when navigating from visual images or maps that may be presented in different orientations, and usually results in slower recognition and lower accuracy.

miss

miss n. in signal detection tasks, an incorrect indication by the participant that a signal is absent in a trial when it is actually present. See also false rejection; signal detection theory. Compare false alarm.

missing at random (MAR)

Sorry, "missing-at-random-mar" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

missing fundamental

missing fundamental see virtual pitch.

missing-parts test

missing-parts test an intelligence test in which the participant is required to point out what is missing in a picture. It is frequently used as an observation test in IQ scales, such as the Stanford–Binet Intelligence Scale and the Wechsler Adult Intelligence Scale.

missionaries and cannibals problem

missionaries and cannibals problem in studies of problem solving, a task proposing that three missionaries and three cannibals are on one side of a river and must cross to the other side in a canoe that will only hold two people. The missionaries on either bank must never be outnumbered by the cannibals or they will be eaten, and the canoe must have at least one passenger each time it crosses the river. The solver must plan a series of moves that will get the group across the river in a way that meets these constraints.

misspecification

misspecification n. the situation in which the number of variables, factors, parameters, or some combination of these was not correctly specified in a statistical model, with the result that the model does not offer a reasonable representation of obtained data. Misspecification is indicated by such things as large residuals between the data and that predicted by the model, large standard errors for the parameter estimates, values for the parameter estimates outside of the normal range (e.g., Heywood cases), or a nonsignificant result from a goodness-of-fit test.

mistress

mistress n. a woman with whom a married man has a continuing sexual relationship, usually without the knowledge of his wife.

mistrust

mistrust n. see basic trust versus mistrust.

MIT

MIT abbreviation for melodic intonation therapy.

mitigating factor

mitigating factor a fact relating to a crime or to a convicted defendant that supports the argument for a more lenient sentence. Examples of mitigating factors are the defendant’s youth, personal or family circumstances, or diminished responsibility. Also called mitigating circumstance. Compare aggravating factor.

mitochondrion

mitochondrion n. (pl. mitochondria) an organelle that is the main site of energy production in cells. Mitochondria are most numerous in cells with a high level of metabolism. They have their own DNA (mitochondrial DNA). —mitochondrial adj.

mitosis

mitosis n. (pl. mitoses) the type of division of a cell nucleus that produces two identical daughter nuclei, each possessing the same number and type of chromosomes as the parent nucleus. It is usually accompanied by division of the cytoplasm, leading to the formation of two identical daughter cells. Compare meiosis. —mitotic adj.

mitral cell

mitral cell any of the pyramidal cells that form a layer of the olfactory bulb. Each mitral cell may receive signals from hundreds of olfactory receptors embedded in the olfactory epithelium. See also lateral olfactory tract.

mittelschmerz

mittelschmerz n. a pain experienced by some females about midway through the menstrual cycle—that is, at the time of ovulation (from German, “midpain”). The pain is felt in the region of the ovary and is caused by the rupture of the ovarian follicle and bleeding into the peritoneum.

Mitwelt

Mitwelt n. in the thought of German philosopher Martin Heidegger (1889–1976), that aspect of Dasein (being-in-the-world) that is constituted by a person’s relationships and interactions with other people. It was introduced into psychology by Swiss existentialist psychologist Ludwig Binswanger (1881–1966). Compare Eigenwelt; Umwelt. [German, literally: “with world”]

mixed cerebral dominance

mixed cerebral dominance a condition in which neither cerebral hemisphere clearly controls motor functions, possibly causing speech disorders or conflicts in handedness.

mixed deafness

mixed deafness see deafness.

mixed design

mixed design a study that combines features of both a between-subjects design and a within-subjects design. Thus, a researcher examines not only the potential differences between two or more separate groups of participants but also assesses change in the individual members of each group over time. For example, a researcher might use a mixed design to study the influence of different types of music on relaxation. He or she could divide participants into a control group (listening to no music) and two experimental groups (one listening to classical music and one listening to rock music). The researcher could administer a pretest to participants in all groups in order to determine the baseline level of physiological arousal prior to hearing any music and then introduce the music and test participants while they listen. After stopping the music, he or she could administer another test (a posttest) to determine what specific reduction in arousal may have occurred throughout the listening period. In this situation, music type is a between-subjects factor (each participant hears only a single genre of music) and physiological arousal is a within-subjects factor (each participant is evaluated on this variable on multiple occasions and the different assessments compared).

mixed distribution

mixed distribution a distribution in which the variables may take on both a discrete and a continuous range of values. This may occur when a continuously measured variable is abruptly topped off or bottomed out at an arbitrary value for a number of participants in the sample. For example, consider a health researcher studying the effects of a smoking cessation intervention who records the number of days since a participant quit smoking. For those participants who quit, the number of days will reflect an infinite series of potential values, whereas for those who continue to smoke the number of days will be the single finite value of zero.

mixed dysarthria

mixed dysarthria see dysarthria.

mixed emotions

mixed emotions two or more emotions, differing in feeling quality and action tendency, elicited by the same event. For example, a father may be happy that his son is getting married but sorrowful if the marriage takes the son away from home; a person may become angry at an insult from a superior and also frightened by the implications for his or her employment. Also called mixed feelings. See ambivalence.

mixed episode

mixed episode in DSM–IV–TR, an episode of a mood disorder in which symptoms meeting criteria for both a major depressive episode and a manic episode are prominent over the course of the disturbance. One or more mixed episodes may be a feature of bipolar disorder. In DSM–5, the specifier “with mixed features” is used instead of mixed episode to characterize the presence of these symptoms.

mixed laterality

mixed laterality the tendency to shift preference from the right side of the body to the left side when performing a particular activity, or to perform some acts with a preference for the right-hand side and others with a preference for the left. Also called lateral confusion.

mixed model

mixed model see mixed-effects model.

mixed receptive-expressive language disorder

mixed receptive-expressive language disorder in DSM–IV–TR, a developmental communication disorder that combines the symptoms of expressive language disorder with the symptoms of semantic comprehension problems, leading to difficulty with word associations, categorization, and verbal mediation in general.

mixed reinforcement schedule

mixed reinforcement schedule a compound schedule of reinforcement in which two or more schedules alternate. The same stimulus is used for all schedules, therefore no discriminative cues are available (see discriminative stimulus).

mixed schizophrenia

mixed schizophrenia 1. a form of schizophrenia in which both negative and positive symptoms are prominent or neither is prominent. [defined in 1982 by U.S. psychiatrists Nancy C. Andreasen and Scott A. Olsen] 2. historically, a form of schizophrenia that is manifested by symptoms of two or more of the four major types of schizophrenia described by Emil Kraepelin and Eugen Bleuler: simple, paranoid, catatonic, and hebephrenic (disorganized).

mixed transcortical aphasia (MTcA)

Sorry, "mixed-transcortical-aphasia-mtca" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mixed-design analysis of variance

mixed-design analysis of variance see mixed-model analysis of variance.

mixed-effects design

mixed-effects design a vague term used to denote an approach to either research or analysis—the mixed design or the mixed-effects model, respectively.

mixed-effects model

mixed-effects model any statistical procedure or experimental design that uses one or more independent variables whose levels are specifically selected by the researcher (fixed effects; e.g., gender) and one or more additional independent variables whose levels are chosen randomly from a wide range of possible values (random effects; e.g., age). Also called mixed model. Compare fixed-effects model; random-effects model.

mixed-function antidepressant

mixed-function antidepressant see multifunctional antidepressant.

mixed-methods research

mixed-methods research a study that combines aspects of both qualitative research and quantitative research so as to understand the phenomenon of interest more fully. For example, a researcher studying a disease could conduct a focus group with a set of individuals who would share their experiences in dealing with the disease, and then supplement those qualitative findings by surveying a different set of individuals to obtain quantitative knowledge of risk factors for the disease.

mixed-model analysis of variance

mixed-model analysis of variance a two-way analysis of variance in which one independent variable has fixed levels specifically chosen for investigation (e.g., gender) and the other has levels randomly selected from among many possible conditions (e.g., doses of a drug). It is one of many types of mixed-effects models. Also called mixed-design analysis of variance.

mixed-motive game

mixed-motive game any simulation of social interaction that combines opportunities for coordination with antagonistic motivations. The prisoner’s dilemma game, for example, is structured so that players can reach their goals either by competing against or by cooperating with others. See also social dilemma; social trap.

mixed-standard scale

mixed-standard scale a behavior-based rating procedure used in employee evaluation. Raters are presented with examples of good, average, and bad behaviors for a job and told to evaluate the performance of the employee in terms of whether it is better than, the same as, or poorer than each of the three behaviors. The performance rating is assigned on the basis of the pattern of responses, the highest score being given to employees rated “better than” on all three behaviors and the lowest rating being given to those rated “poorer than” on all three. Compare behaviorally anchored rating scale; behavioral observation scale. See also critical-incident technique.

mixoscopia

mixoscopia n. a form of voyeurism in which an orgasm is achieved by observing sexual intercourse between the person one loves and another person.

mixoscopia bestialis

mixoscopia bestialis a type of sexual deviancy in which a person is excited or aroused by watching another individual have coitus with an animal.

MLD

MLD abbreviation for masking level difference.

MLE

MLE abbreviation for maximum likelihood estimation.

MLH1

MLH1 a germ-line mutation located on the short arm of chromosome 3 and associated with hereditary nonpolyposis colorectal cancer (HNPCC). See also MSH2.

MLU

MLU abbreviation for mean length of utterance.

MMECT

MMECT abbreviation for multiple monitored electroconvulsive treatment.

MMPI

MMPI abbreviation for Minnesota Multiphasic Personality Inventory.

MMSE

MMSE abbreviation for Mini-Mental State Examination.

MMT

MMT abbreviation for multimodal therapy.

mneme

mneme n. see engram.

mnemonic

mnemonic n. any device or technique used to assist memory, usually by forging a link or association between the new information to be remembered and information previously encoded. For instance, one might remember the numbers in a password by associating them with familiar birth dates, addresses, or room numbers. Also called memory aid; mnemonic system. See also key-word method; method of loci; peg-word mnemonic.

mnemonic trace

mnemonic trace see engram.

mnemonist

mnemonist n. an individual with exceptional ability to encode and retrieve information from memory. Some mnemonists have well-developed memory strategies that enable them to remember; others have exceptional memories in only certain domains (e.g., numbers or foreign words).

mnestic

mnestic adj. related to memory.

mob

mob n. a disorderly, unruly, and emotionally charged crowd. Mobs tend to form when some event, such as a crime, a catastrophe, or a controversial action, evokes the same kind of mood and reaction in a substantial number of people. Early analyses argued that individuals in mobs were so overwhelmed by their emotions and the group mind that they could no longer control their actions: Unless the situation was diffused, mobs became volatile, unpredictable, and capable of violent action. Contemporary studies suggest that members of mobs may respond impulsively but rarely lose cognitive control, that mysterious social or psychological processes do not force them to behave abnormally in such situations, and that mobs tend to be organized and goal-directed rather than irrational and frenzied.

mob psychology

mob psychology crowd psychology, as applied to mobs.

Moban

Moban n. a former trade name for molindone.

mobbing

mobbing n. a behavior observed in groups of small birds and mammals when threatened by a predator in which group members join together to chase the predator away. Mobbing is usually accompanied by loud, distinctive vocalizations.

mobility

mobility n. 1. the capacity to move or be moved, such as the ability of people to transport themselves between home and work or community facilities by such means as walking, driving a car, or traveling by public transportation. See also motility. 2. the ability of an infant to creep, crawl, walk, or otherwise move through space. 3. in sociology, the extent to which individuals are able to move between localities, occupations, or social classes. See geographical mobility; social mobility. See also horizontal mobility; vertical mobility. —mobile adj.

MoCA

MoCA abbreviation for Montreal Cognitive Assessment.

MOCC

MOCC abbreviation for memory-operating characteristic curve.

moclobemide

moclobemide n. an antidepressant drug that is a reversible monoamine oxidase inhibitor and relatively selective for monoamine oxidase A. It therefore lacks many of the food interactions that limit the use of irreversible, nonselective MAO inhibitors. Moclobemide has not yet been approved for use in the United States.

modafinil

modafinil n. a CNS stimulant used for the treatment of narcolepsy that may serve as an alternative agent for patients who are intolerant of amphetamines and related stimulants. Its exact mechanism of action is unclear, but because it inhibits the cytochrome P450 2C19 enzyme and induces the cytochrome P450 3A4 enzyme, it may have clinically significant interactions with drugs metabolized via those enzymes. U.S. trade name: Provigil. The related drug armodafinil is used in the treatment of narcolepsy, sleep apnea, and shift-work sleep disorder. U.S. trade name: Nuvigil.

modal

modal n. pertaining to a particular mode, model, technique, or process. In linguistics, modal refers to the mood of a verb; that is, for example, whether it is indicative (states a fact), imperative (expresses an order or command), or subjunctive (expressing a wish or a state of possibility).

modal action pattern (MAP)

Sorry, "modal-action-pattern-map" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

modal frequency

modal frequency the number of respondents who have the score that occurs most often in a set of data (i.e., the mode). For example, in a small sample of college freshmen whose ages are 18, 18, 18, 19, 19, 20, 20, 21, 23, and 25 the modal frequency for age is 3: The most commonly occurring score is 18 and there are three people with such a score.

modal model of memory

modal model of memory a generic theory of memory incorporating assumptions common to most models. The modal model includes a short-term memory and a long-term memory and provides details on how information is encoded and later retrieved from memory. See also dual-store model of memory; multistore model of memory.

modality

modality n. 1. a particular therapeutic technique or process (e.g., psychodynamic). 2. a medium of sensation, such as vision or hearing. See sense.

modality effect

modality effect the tendency for the final items of a list to be better recalled if the items are presented auditorily rather than visually.

mode

mode n. 1. a characteristic manner of behavior or way of doing things, as in a technique. 2. the most frequently occurring score in a set of data, which is sometimes used as a measure of central tendency. Also called modal value.

MODE theory

MODE theory Motivation and Opportunity as Determinants theory: a theory of attitude–behavior consistency postulating that the process by which attitudes influence behavior differs according to the amount of deliberation involved. When people are motivated and able to deliberate about their actions, attitudes influence behavior in a manner similar to that postulated by the theory of reasoned action. When people are not motivated or able to deliberate about their actions, attitudes toward the target of the behavior can be activated in memory and affect the way the target is perceived. These perceptions in turn influence how people define the behavioral event (e.g., as a situation in which the target should be approached or avoided). The definition of the behavioral event in turn determines behavior. [originally developed by U.S. psychologist Russell H. Fazio (1952– )]

model

model n. 1. a graphic, theoretical, or other type of representation of a concept or of basic behavioral or bodily processes (e.g., a disorder) that can be used for various investigative and demonstrative purposes, such as enhancing understanding of the concept or process, proposing hypotheses, showing relationships, or identifying epidemiological patterns. 2. see modeling.

model human processor

model human processor a model of human information processing that is used in evaluating the usability of products and systems. The model, which is derived from empirical findings, consists of three interacting subsystems—perceptual, motor, and cognitive. Estimates of processing capacity and of processing and decay times (see decay theory) can be used to quantify human performance under a variety of constraints. See also human operator modeling. [developed in 1983 by U.S. psychologist Stuart K. Card (1943– ), U.S. computer scientist Thomas P. Moran (1942– ), and U.S. cognitive and computer scientist Allen Newell (1927–1992)]

model psychosis

model psychosis psychotic symptoms (e.g., delusions, hallucinations, disorientation, disorganized speech) deliberately produced by a psychotomimetic drug, such as LSD, for purposes of research. This technique was particularly popular during the 1950s and 1960s.

modeling

modeling n. 1. a technique used in cognitive behavior therapy and behavior therapy in which learning occurs through observation and imitation alone, without comment or reinforcement by the therapist. See also behavioral modeling. 2. the process in which one or more individuals or other entities serve as examples (models) that a child will emulate. Models are often parents, other adults, or other children, but they may also be symbolic (e.g., a book or television character). See also social learning theory.

modeling effect

modeling effect a type of experimenter effect in which a participant is unwittingly influenced to give responses similar to the responses the experimenter would give if the experimenter were a participant.

modeling theory

modeling theory the idea that changes in behavior, cognition, or emotional state result from observing someone else’s behavior or the consequences of that behavior. See observational learning; social learning theory.

moderate mental retardation

moderate mental retardation an older diagnostic and classification category applying to those with IQs of 35 to 49, comprising about 10% of people with mental retardation. These individuals rarely progress beyond the second grade in academic subjects. Although often poorly coordinated, they can learn to take care of themselves and to develop sufficient social and occupational skills to be able to perform unskilled or semiskilled work under supervision in sheltered and supportive environments, as well as in regular workplaces where accommodations are made.

moderating effect

moderating effect the effect that occurs when a third variable changes the nature of the relationship between a predictor and an outcome, particularly in analyses such as multiple regression. For example, structural equation modeling can be used to assess whether a predicted association between quantitative skill and performance fits equally well across different teaching style groups (e.g., lecture based vs. hands-on learning). If the prediction is different across the two groups, then teaching style is said to have produced a moderating effect. Also called moderator effect.

moderator

moderator n. 1. an independent variable that changes the nature of the relationship between other variables. For example, if a researcher examined the relationship between gender and math performance, a significant difference might emerge. However, if teaching style were taken into account, such that those who learned math by applied, hands-on methods performed better than those who learned with traditional lecture styles, regardless of gender, one could say that teaching style was a moderator of the relationship between gender and math performance. Also called moderating variable. See also moderating effect. 2. a variable aspect of consumer behavior associated with different patterns of results. For example, consumer motivation might serve as a moderator of how individuals develop attitudes toward products. With high levels of motivation, consumers tend to base their attitudes on the quality of a product as assessed by detailed thinking about the product’s features. With low levels of motivation, consumers tend to base their attitude toward a product on such factors as the attractiveness of the product endorser. Personality variables often serve as moderators of processes underlying consumer behavior.

modern racism

modern racism a contemporary form of prejudice against members of other racial groups that is expressed indirectly and covertly, typically by condemning the cultural values of the outgroup or by experiencing aversive emotions when interacting with its members but not acting on those negative emotions (see aversive racism). A modern racist, for example, expresses prejudice by condemning another group’s cultural values or by avoiding any contact with members of that group. Changed social attitudes have brought about a decline in the direct expression of racial discrimination and hostility toward minority groups (old-fashioned racism), with a corresponding increase in the less blatant modern racism.

modernism

modernism n. 1. in philosophy, a set of general characteristics marking the whole period from the 17th century to the present day. Most historians of philosophy see the onset of modernity in the work of René Descartes, with its attempt to establish a systematic account of reality on a radically new basis (see Cartesianism; Cartesian dualism; Cartesian self). Historically, modernism is inseparable from the Enlightenment of the 17th and 18th centuries and its complex legacy over the past 300 years. Its defining characteristics include a sense that religious dogma and classical metaphysics can no longer provide a sure foundation in intellectual matters and a quest for certain knowledge from other sources; the latter is sustained by confidence in absolutes in epistemology and ethics and confidence in the new methods of experimental philosophy, or natural science. Traditional psychology can be seen to be the product of modernism to the extent that it is characterized by faith in scientific method, pursuit of control and prediction of behavior, explanation in terms of laws and principles, and the assumption that human behavior is ultimately rational as opposed to irrational. Some thinkers argue that modernism was superseded by postmodernism in the late 20th century, although others would dispute such a claim. 2. a movement in the arts of the early 20th century characterized by the adoption of radically new techniques, forms, approaches, and subjects. Important developments associated with modernism include abstraction in the visual arts, free verse in poetry, and use of the 12-tone scale in music. Many writers and artists of the period were influenced by contemporary developments in psychology and psychoanalysis; a particular instance of this is the use of the stream of consciousness technique by novelists and poets, such as Irish writer James Joyce (1882–1941), British writer Virginia Woolf (1882–1941), French writer Marcel Proust (1871–1922), and others. For more than a half century now, the concept of postmodernism in the arts has been much discussed. —modernist adj., n.

modernization

modernization n. the complex set of processes by which a largely rural and traditional society becomes a developed industrial society. Modernized societies are typically conceived as those societies that tend toward the secular and urbanized and that place a high value on science and technology, education, social mobility, acquired wealth, democratic government, and the rule of law. Modernization is anchored to notions of social and economic progress. It is often contrasted with the traditionalism of undeveloped or underdeveloped societies, which are often identified as religious and rural, with limited technology, low social mobility, weak political structures, and so forth. Other conceptualizations of this dichotomy are currently in debate, however, pointing to the highly variable social and psychological adjustments that occur in different societies as they respond to development. —modernize vb.

modes of learning

modes of learning different sensory modalities through which information may be presented for learning and encoded into memory. For instance, one can learn through vision, hearing, or touch. See motor learning; verbal learning; visual learning.

modesty

modesty n. 1. absence of self-importance or conceit. 2. propriety in appearance, dress, demeanor, and social behavior. —modest adj.

modified replication

modified replication see replication.

Modified Rhyme Test (MRT)

Sorry, "modified-rhyme-test-mrt" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

modifier

modifier n. 1. in genetics, a gene that appears to have an effect of modifying other hereditary factors but has no significant effect when those other factors are absent. Some investigators believe modifier genes play a role in constitutional medical conditions. Many physical diseases and behaviors are thought to involve modifier genes as well as environmental triggers. 2. in grammar, any word or phrase that qualifies or limits the meaning of another word or phrase (e.g., an adjective or adverb).

modularity

modularity n. a theory of the human mind in which the various components of cognition are characterized as independent modules, each with its own specific domain and particular properties. It was first proposed by U.S. philosopher Jerry Fodor (1935– ) in his book The Modularity of Mind (1983). A related notion had earlier been advanced by Noam Chomsky in his theory of the task specificity of language, which characterizes the human language faculty as a unique “mental organ” differing qualitatively from other aspects of cognition. More recently, evolutionary psychologists have shown interest in the idea that the various modules may be adaptive specializations. Compare cognitive grammar.

modulation

modulation n. changes in some parameter of a waveform (e.g., amplitude, frequency, phase) so that the information contained by the variations of this parameter can be transmitted by the wave, which is known as the carrier wave. Amplitude modulation (AM) refers to changes in amplitude that are relatively slow compared to the usually sinusoidal variations in the carrier. In frequency modulation (FM), the frequency of the carrier is varied, but its amplitude remains constant. In phase modulation, the relative phase of the carrier wave is varied in accordance with the amplitude of the signal variations. For most modulated waveforms, the frequency of modulation is much less than the frequency components in the carrier.

modulation threshold

modulation threshold see temporal modulation transfer function.

modulatory role

modulatory role the role that some hormones play in maintaining the sensitivity of neural circuits and other structures to hormonal influences.

modulatory site

modulatory site a site on a receptor molecule that, when bound by a ligand (e.g., a drug), alters the receptor’s response on binding of its agonist (e.g., a neurotransmitter) to the usual site.

module

module n. 1. in cognitive theory, a hypothetical center of information processing that is presumed to be relatively independent and highly specialized in its operations, such as a language module or face-processing module. 2. in neuroscience, a unit of a region of the central nervous system. For example, regions of the neocortex in the brain are divided into cortical columns of basically similar structure. —modular adj.

modulus

modulus n. see absolute value.

modus operandi

modus operandi a specific behavioral pattern that may typify a particular individual; the term is often used with respect to criminal behavior but also more generally to signify any individual’s particular behavioral approach or way of acting. [from Latin, “manner of working”]

MOE

MOE abbreviation for margin of error.

Mogadon

Mogadon n. a trade name for nitrazepam.

mogigraphia

mogigraphia n. a rare name for writer’s cramp.

mogilalia

mogilalia n. difficulty or hesitancy in speaking (e.g., stuttering). Also called molilalia.

moiré interference model

moiré interference model see grid cell.

molar

molar adj. characterized by or pertaining to units, masses, and systems in their entirety. Molar analysis (also called global analysis) in psychology is a way of examining behavioral processes as holistic units, extended through time. This approach stresses comprehensive concepts or overall frameworks or structures. Compare molecular.

molecular

molecular adj. characterized by or pertaining to the component parts of a phenomenon, process, or system. Molecular analysis in psychology is a way of examining behavioral processes in terms of elemental units, sometimes analyzing them in a moment-by-moment or phase-by-phase manner. Compare molar.

molecular genetics

molecular genetics the branch of biology that is concerned with the structure and processes of genetic material at the molecular level.

molecular layer

molecular layer see dentate gyrus.

molecularism

molecularism n. see atomism.

molestation

molestation n. the act of making sexual advances toward a person who does not want them. Molestation generally implies sexual fondling or touching an individual without lawful consent. When the victim of molestation is a child or a person with a mental disability, it may be assumed that he or she does not have the capacity to give lawful consent. See also sex offense. —molest vb.

molilalia

molilalia n. see mogilalia.

molindone

molindone n. a conventional (typical or first-generation) antipsychotic. Until the advent of the atypical, or second-generation, antipsychotics, it was frequently used, usually in low doses, for the management of psychoses accompanying medical conditions (e.g., HIV-related dementia). Molindone was taken off the U.S. market in 2010. Former U.S. trade name: Moban.

Molyneux’s question

Molyneux’s question the question posed by William Molyneux (1656–1698), a member of the Irish parliament, to John Locke, who later discussed it in his Essay Concerning Human Understanding (1690). Molyneux’s question was whether a man born blind but able to distinguish two distinct shapes by feeling them with his hands would be able to distinguish them by sight alone, without also touching them, if he were suddenly able to see. Locke’s answer—and Molyneux’s as well—was that the person would not be able to distinguish them by sight immediately because the sense modalities act independently and can be integrated only by experience.

moment

moment n. the power to which the expected value of a random variable is raised. Thus, E(xk) is the kth moment of x. The first moment is usually the mean of a variable, the second moment refers to variance, the third moment relates to skewness, and the fourth moment concerns kurtosis. Knowing each of these moments provides a complete picture of the distribution for a set of scores: A researcher knows the center point of the data, how spread out the values are, whether they are lopsided, and whether they are peaked (leptokurtic) or flat (platykurtic).

moment about the mean

moment about the mean see central moment.

mommy track

mommy track 1. a professional pathway associated with working mothers, typically characterized by flexible working conditions but limited career advancement. 2. the cultural and social circumstances that put girls on the path to early motherhood; poor socioeconomic circumstances and the lack of a strong, present, and positive father figure can influence girls to become mothers earlier in their lives than girls with more advantages.

mon-

Sorry, "mon" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

monad

monad n. in the thought of Gottfried Wilhelm Leibniz, one of the ultimate indivisible units of existence. Monads are independent of one another and innately have the power of action and direction toward some end (see nisus). Although no monad in reality acts on any other, they work in a divinely preestablished harmony so that an appearance of causal connection is maintained. The concept of the monad was intended, in part, to address the mind–body problem arising from Cartesian dualism.

monaural

monaural adj. relating to or perceived by one ear only. Compare binaural.

monestrous

monestrous adj. see estrous cycle.

mongolism

mongolism n. an obsolete name for Down syndrome.

moniliasis

moniliasis n. see candidiasis.

monism

monism n. the position that reality consists of a single substance, whether this is identified as mind (idealistic monism), matter (natural monism), or God (pantheism). In the context of the mind–body problem, monism is any position (such as neutral monism) that avoids dualism. —monist adj., n. —monistic adj.

mono- (mon-)

Sorry, "mono-mon" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

monoacylglycerol lipase (MAGL)

Sorry, "monoacylglycerol-lipase-magl" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

monoamine

monoamine n. an amine that contains only one amine group, –NH2. Monoamines include neurotransmitters such as the catecholamines norepinephrine and dopamine and the indoleamine serotonin. See also monoamine oxidase.

monoamine hormone

monoamine hormone see amine hormone.

monoamine hypothesis

monoamine hypothesis the theory that depression is caused by a deficit in the production or uptake of the amine compounds serotonin, norepinephrine, and dopamine. This theory has been used to explain the effects of monoamine oxidase inhibitors but is now regarded as too simplistic. A related notion, the monoamine neurotransmitter theory, proposes that runner’s high is the result of an increase of norepinephrine and serotonin with exercise.

monoamine oxidase (MAO)

Sorry, "monoamine-oxidase-mao" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

monoamine oxidase inhibitor (MAOI; MAO inhibitor)

Sorry, "monoamine-oxidase-inhibitor-maoi-mao-inhibitor" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

monochorial twins

monochorial twins a set of twins that, in utero, shared the same outermost embryonic membrane (chorion). Monochorial twins are always identical twins (monozygotic twins), but identical twins are not necessarily monochorial. Compare dichorial twins.

monochromatic light

monochromatic light light of a single wavelength. Monochromatic light can be produced by a laser or by a monochromator, which uses a prism to refract the visible spectrum and a slit to restrict the light available to the viewer to a single wavelength.

monochromatism (monochromacy; monochromasy; monochromatopsia)

Sorry, "monochromatism-monochromacy-monochromasy-monochromatopsia" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

monocular

monocular adj. referring to one eye. Also called uniocular. Compare binocular.

monocular cell

monocular cell see binocular cell.

monocular cue

monocular cue see depth cue.

monocular deprivation

monocular deprivation the deprivation of light to one eye. Compare binocular deprivation.

monocular rearing

monocular rearing an experimental paradigm in which an animal is raised from birth with vision restricted to one eye by suturing the eyelids closed or by inserting an opaque contact lens in one eye. Monocular rearing during the critical period has profound structural and functional consequences for the developing visual system, including a shift in the ocular dominance of cortical neurons to favor the nonoccluded eye and a broadening of the ocular dominance columns corresponding to the open eye.

monocular suppression

monocular suppression the tendency of one eye to be dominant while the other is suppressed, resulting in a failure of binocular vision.

monocular vision

monocular vision the use of only one eye for sight.

monodrama

monodrama n. in group therapy, a role-playing technique in which a member of the group acts out a scene alone. The member’s behavior is then evaluated by the group.

monogamy

monogamy n. 1. a mating system in which two individuals mate exclusively with each other. Recent genetic studies of paternity indicate that some offspring of male–female pairs exhibiting monogamy are not related to the father, leading to a distinction between social monogamy, in which there is an appearance of a close pair bond, and genetic monogamy, in which there is exclusive mating. Many species, including human beings, display serial monogamy, in which there is an exclusive social bond with each of a series of sexual partners at different times during the individual’s life. Compare polyandry; polygynandry; polygyny. 2. traditionally, marriage to only one spouse at a time. Compare polygamy. —monogamous adj.

monogenism

monogenism n. the belief or theory that all human beings are descended from the same two ancestors. Also called monogenesis; monogeny.

monoideism

monoideism n. obsessive preoccupation with a single idea to the exclusion of anything else.

monomania

monomania n. 1. extreme enthusiasm or zeal for a single subject or idea, often manifested as a rigid, irrational idea. See also idée fixe. 2. an obsolete name for a pattern of abnormal behavior with reference to a single subject in an otherwise apparently normally functioning individual. —monomaniac n.

monomorphism

monomorphism n. the absence of differences between males and females of a species such that both sexes are similar in body size, coloration, or other features. Compare dimorphism; sexual dimorphism. —monomorphic adj.

monopediomania

monopediomania n. sexual interest in and arousal by people who have only one leg.

monophagism

monophagism n. a pathological eating behavior in which the individual habitually eats only one type of food or only one meal a day.

monophasic sleep

monophasic sleep a sleep pattern in which sleeping occurs in one long period once a day, typically at night. Compare polyphasic sleep. See also sleep–wake cycle.

monoplegia

monoplegia n. paralysis of a single part of the body, for example, one arm, one leg, or one digit. —monoplegic adj.

monopolar neuron

monopolar neuron see unipolar neuron.

monorchidism

monorchidism n. the condition of having only one testis in the scrotum. The second testis may be present but undescended (see cryptorchidism). See also ectopic testis. —monorchid adj., n.

monorhinic

monorhinic adj. relating to the presentation of an odorant to a single nostril via an olfactometer.

monosomy

monosomy n. see autosome. —monosomic adj.

monosomy 5p

monosomy 5p see cri du chat syndrome.

monosymptomatic

monosymptomatic adj. denoting a disorder that is characterized by a single marked symptom.

monosynaptic arc

monosynaptic arc a simple neural arc that involves just two neurons with a synapse between them, as in the case of a monosynaptic stretch reflex. Also called two-neuron arc. Compare polysynaptic arc. See also reflex arc.

monosynaptic stretch reflex

monosynaptic stretch reflex a reflex in which there is muscle contraction in response to sudden stretching of a tendon, involving only a sensory neuron, a motor neuron, and the synapse connecting them in the spinal cord. The patellar reflex is a monosynaptic stretch reflex. See also reflex arc.

monosynaptic transmission

monosynaptic transmission the transmission of nerve impulses via a single synapse, as in a monosynaptic arc.

monotherapy

monotherapy n. the use of a single method or approach to treat a particular disorder or presenting symptom, as opposed to the use of a combination of methods. An example is the use of only pharmacotherapy, instead of pharmacotherapy and psychotherapy in combination, to treat depression.

monotic

monotic adj. denoting or relating to the presentation of sound to one ear only. Compare dichotic; diotic.

monotonic

monotonic adj. denoting a variable that either increases or decreases as a second variable either increases or decreases, respectively: The relationship is not necessarily linear but there are no changes in direction. A monotonically increasing variable is one that rises consistently as a second variable increases, for example, level of performance in relation to amount of practice if this were observed to be the case. In contrast, depression would be a monotonically decreasing variable if its severity were found to fall consistently as a person’s level of perseveration declined.

monozygotic twins (MZ twins)

Sorry, "monozygotic-twins-mz-twins" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

Monte Carlo research

Monte Carlo research a simulation technique in which a large number of samples with specific selected properties (e.g., normality, size, model type) are generated by computer in order to assess the behavior of a statistical procedure or parameter under varying conditions. For example, an investigator might conduct Monte Carlo research with a large number of normally distributed samples of various sizes (e.g., N = 50, 100, 200, 400, 800) in which a structural model is applied to characterize the data. Results would help the researcher determine the conditions under which the model behaves correctly (i.e., fits the data) as well as shows its limits (e.g., not fitting well with sample sizes less than 200). Also called Monte Carlo method.

Montessori method

Montessori method an educational system that focuses on the development of young children’s initiative and emphasizes self-directed learning. The method is characterized by multiage classrooms, a special set of educational materials, student-chosen work in long time blocks, collaboration, the absence of grades and tests, and individual and small group instruction in both academic and social skills. The system was developed in Italy, with the first American school established in 1911. [Maria Montessori]

Montreal Cognitive Assessment (MoCA)

Sorry, "montreal-cognitive-assessment-moca" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mood

mood n. 1. any short-lived emotional state, usually of low intensity (e.g., a cheerful mood, an irritable mood). 2. a disposition to respond emotionally in a particular way that may last for hours, days, or even weeks, perhaps at a low level and without the person knowing what prompted the state. Moods differ from emotions in lacking an object; for example, the emotion of anger can be aroused by an insult, but an angry mood may arise when one does not know what one is angry about or what elicited the anger. Disturbances in mood are characteristic of mood disorders. 3. in linguistics, a category of a verb used to identify a clause or sentence as being a statement, question, command, expression of wish, and so on. See imperative; indicative; interrogative; subjunctive.

mood congruent

mood congruent relating to a consistency or agreement between a particular expressed feeling and the general emotional context within which it occurs. Thus, crying at a time of sadness or personal distress is viewed as mood congruent. Similarly, in psychiatric diagnosis, the term relates to a consistency between the expression of a particular symptom or behavior with those characteristics or patterns of ideation or action used to classify a particular mental disorder. In both instances, inconsistencies are described as mood incongruent.

mood disorder

mood disorder in DSM–IV–TR, a psychiatric condition in which the principal feature is a prolonged, pervasive emotional disturbance, such as a depressive disorder, bipolar disorder, or substance-induced mood disorder. Also included are mood disorders due to a general medical condition, in which attendant physiological disruptions are believed to produce the emotional changes, and mood disorder not otherwise specified, which does not meet the diagnostic criteria for any of the specific mood disorders. The term chronic mood disorder is applied when symptoms rarely remit. In DSM–5, mood disorders are divided into two categories: bipolar and related disorders, which include bipolar disorder and its subtypes (e.g., bipolar I, bipolar II, cyclothymic disorder); and depressive disorders (e.g., major depressive disorder, persistent depressive disorder or dysthymic disorder, premenstrual dysphoric disorder). Also called affective disorder.

mood incongruent

mood incongruent see mood congruent.

mood induction

mood induction any method for producing a negative or positive change in mood, often by selectively reminding individuals of pleasant or unpleasant aspects of their lives. See Velten technique.

mood stabilizer

mood stabilizer any of various drugs used in the treatment of cyclic mood disorders (bipolar disorders and cyclothymic disorder). Because they reduce the symptoms of mania or manic episodes, mood stabilizers are sometimes known as antimanic drugs. Lithium is usually the first-line medication for bipolar I disorder, but anticonvulsants, such as valproic acid, carbamazepine, and oxcarbazine, are becoming more commonly used for this condition and are now preferred for other cyclic disorders. The calcium-channel blocker verapamil is also being investigated as a mood stabilizer. Mood stabilizers are occasionally used in the management of severe affective lability found in some personality disorders (e.g., borderline personality disorder).

mood swing

mood swing a nonspecific term for any oscillation in mood, particularly between feelings of happiness and sadness. It may range in intensity from normal fluctuations to such pathological disturbances as cyclothymic disorder or bipolar disorder. See also labile affect.

mood-altering drug

mood-altering drug a substance that changes the affective state of the individual through pharmacological action, usually without clouding of consciousness. Such drugs include certain tranquilizing, sedating, and antidepressant agents.

mood-as-information theory

mood-as-information theory a theory postulating that a person often uses his or her current emotional state or mood as a piece of information when making social judgments. The theory also proposes that current affective states can influence the processing strategy that people adopt when making decisions. Specifically, negative affective states indicate something problematic in the current social situation and thus encourage careful and deliberative processing of social information. In contrast, positive affective states indicate that the current social situation is satisfactory and thus encourage less effort in deliberative processing of social information. [originally developed by U.S. psychologists Norbert Schwarz (1953– ), Gerald L. Clore (1939– ), and their colleagues]

mood-as-resource model

mood-as-resource model a theory stating that positive moods function as useful tools to individuals by making them better able to process goal-related information, better at coping with negative stimuli, and more flexible and constructive in dealing with situational demands.

mood-congruent memory

mood-congruent memory consistency between one’s mood state and the emotional context of memories recalled. During positive mood states, individuals will tend to retrieve pleasant memories, whereas during negative mood states, negative thoughts and associations will more likely come to mind. However, there is evidence that the effects of these different mood states on memory are asymmetrical, with positive moods having stronger effects on memory retrieval than negative moods. When faced with an unpleasant emotional state, individuals may regulate it by retrieving pleasant thoughts and memories, thus reducing or reversing a negative mood-congruency effect. [first proposed in 1985 by U.S. social psychologist Alice M. Isen (1942–2012)]

mood-congruent psychotic feature

mood-congruent psychotic feature a DSM–IV–TR and DSM–5 specification for any delusion or hallucination that is thematically consistent with either sadness or mania when it occurs in severe major depressive episodes, manic episodes, or mixed episodes.

mood-dependent memory

mood-dependent memory the finding that memory for an event can be recalled more readily when one is in the same emotional mood (e.g., happy or sad) as when the memory was initially formed. See also context-specific learning; state-dependent memory.

mood-incongruent psychotic feature

mood-incongruent psychotic feature a DSM–IV–TR and DSM–5 specification for any delusion or hallucination that occurs in severe major depressive episodes, manic episodes, or mixed episodes but whose content does not include themes of sadness or mania.

moon illusion

moon illusion see size–distance paradox.

moon-phase studies

moon-phase studies research into the possible relationship between the phases of the moon and episodes of violence or mental disorder. The relationship has long been expressed in folklore, folk medicine, and language itself (e.g., the words lunacy and lunatic). Methodologically sound studies of the effects of moon phase on behavior, however, are infrequent.

moral

moral adj. 1. relating to the distinction between right and wrong behavior. 2. describing a behavior that is considered ethical or proper, or a person or group who adheres to a moral code. See also morals.

moral absolutism

moral absolutism the belief that the morality or immorality of an action can be judged according to fixed standards of right and wrong. According to Jean Piaget, moral absolutism is characteristic of young children in the heteronomous stage of moral development, who interpret laws and rules as absolute. See moral realism. Compare moral relativism; situation ethics.

moral code

moral code a set of rules concerning right and wrong behavior accepted by a society or group as binding on all members or by an individual as binding on himself or herself.

moral commitment

moral commitment in U.S. sociologist Michael P. Johnson’s tripartite model of marital commitment, a form of commitment in which a person feels tied to a relationship because of a sense of moral or ethical obligation or duty. Moral commitment often reflects religious or societal beliefs, but it may also derive from an individual’s values about the importance of acting in a manner that affirms one’s vows, promises, and obligations. Compare personal commitment; structural commitment.

moral consistency

moral consistency a stable, predictable pattern of moral attitudes shown by the same individual in different settings and over time.

moral determinism

moral determinism see ethical determinism.

moral development

moral development the gradual formation of an individual’s concepts of right and wrong, conscience, ethical and religious values, social attitudes, and behavior. Some of the major theorists in the area of moral development are Sigmund Freud, Jean Piaget, Erik Erikson, and Lawrence Kohlberg.

moral dilemma

moral dilemma see ethical dilemma.

moral exclusion

moral exclusion a psychological process whereby opponents in a conflict come to view each other as undeserving of morally mandated rights and protections. Moral exclusion can lead to a range of acts, from discrimination to terrorism and genocide. See also dehumanization.

moral independence

moral independence the state an older child has achieved when he or she can recognize that an act’s morality may be substantially determined by its motive and other subjective considerations, rather than by its consequences. Moral independence is a mark of the autonomous stage of moral development. See also moral relativism. Compare moral realism. [proposed by Jean Piaget]

moral judgment

moral judgment see ethical judgment.

moral masochism

moral masochism in psychoanalytic theory, the unconscious need for punishment by authority figures caused by unconscious guilt arising from the repressed Oedipus complex. It is a nonsexual form of masochism.

moral nihilism

moral nihilism the assertion that there exist no valid moral principles. This position is distinct from moral relativism, which merely claims that there are no universally valid moral principles. Also called ethical nihilism.

moral philosophy

moral philosophy see ethics.

moral realism

moral realism the type of thinking characteristic of younger children, who equate good behavior with obedience just as they equate the morality of an act only with its consequences. For example, 15 cups broken accidentally would be judged to be a far worse transgression than 1 cup broken mischievously, because more cups are broken. Moral realism shapes the child’s thinking until the age of about 8, when the concepts of intention, motive, and extenuating circumstances begin to modify the child’s early moral absolutism. Compare moral relativism. [postulated by Jean Piaget]

moral relativism

moral relativism the belief that the morality or immorality of an action is determined by social custom rather than by universal or fixed standards of right and wrong. According to Jean Piaget, moral relativism is characteristic of children in the autonomous stage of moral development, who consider the intention behind an act along with possible extenuating circumstances when judging its rightness or wrongness. Compare moral absolutism; moral realism; situation ethics.

moral therapy

moral therapy a form of psychotherapy from the 19th century based on the belief that a person with a mental disorder could be helped by being treated with compassion, kindness, and dignity in a clean, comfortable environment that provided freedom of movement, opportunities for occupational and social activity, and reassuring talks with physicians and attendants. This approach advocating humane and ethical treatment was a radical departure from the prevailing practice at that time of viewing the “insane” with suspicion and hostility, confining them in unsanitary conditions, and routinely abusing them through the use of such practices as mechanical restraint, physical punishment, and bloodletting. Moral therapy originated in the Gheel colony, Belgium, during the 13th century, but it came to fruition in the 19th century through the efforts of Philippe Pinel (see Salpêtrière) and Jean Esquirol (1772–1840) in France; William Tuke (1732–1822) in England; and Benjamin Rush (1745–1813), Isaac Ray (1807–1881), and Thomas Kirkbride (1809–1883) in the United States. The therapeutic community of today has its roots in this movement. Also called moral treatment.

morale

morale n. the level of enthusiasm, sense of purpose, or confidence in the worthiness of a goal that can affect a person’s or a group’s overall performance in working toward that goal, especially when under pressure.

morality

morality n. a system of beliefs or set of values relating to right conduct, against which behavior is judged to be acceptable or unacceptable.

morality of constraint

morality of constraint the morality of young children (up to roughly age 10), which consists of an unquestioning, unchallenging obedience to the rules laid down by parents. Obedience is based on fear and on the perception that rules established by parents are fixed, eternal, and sure to be valid. Compare morality of cooperation. [proposed by Jean Piaget]

morality of cooperation

morality of cooperation the morality of children ages 10 to 11, characterized by the perception that rules are social conventions that can be challenged and modified when concerned parties agree. The child willingly accepts rules and adheres to them on the basis of reason and not on the basis of fear or in the spirit of unquestioning obedience. Compare morality of constraint. [proposed by Jean Piaget]

morals

morals pl. n. the ethical values or principles that people use to guide their behavior. See also moral; morality.

moratorium

moratorium n. in Erik Erikson’s theory of psychosocial development, the experimental period of adolescence in which, during the task of discovering who one is as an individual separate from family of origin and as part of the broader social context, young people try out alternative roles before making permanent commitments to an identity. Adolescents who are unsuccessful at negotiating this stage risk confusion over their role in life. See identity versus identity confusion. See also identity status model.

morbid

morbid adj. unhealthy, diseased, or otherwise abnormal.

morbid dependency

morbid dependency excessive reliance on or need for another person or situation such that the dependent person has difficulty functioning independently. See dependency need.

morbid jealousy

morbid jealousy see delusional jealousy.

morbid obesity

morbid obesity the condition of having a body mass index over 39 or weighing 50% to 100% over one’s ideal weight. Morbid obesity is associated with diabetes mellitus, heart disease, joint pain, sleep apnea, and stroke.

morbidity

morbidity n. a pathological (diseased) condition or state, either biological or functional.

morbidity rate

morbidity rate the incidence of disease, expressed as a ratio denoting the number of people in a population who are ill or have a specific disease compared with the number who are well.

morbidity risk

morbidity risk in epidemiology, the statistical chance that an individual will develop a certain disease or disorder. The probability is often expressed in terms of risk factors, using 1.0 as a base: The larger the number, the greater the morbidity risk.

Morel’s syndrome

Morel’s syndrome see Stewart–Morel syndrome.

mores pl. n. social customs and usages that are accepted by members of a culture or population as morally essential and necessary for its proper functioning.

Morgan’s canon

Morgan’s canon see Lloyd Morgan’s canon.

moria

moria n. an obsessive or morbid desire to joke, as in some cases of dementia, particularly when the humor is inappropriate.

Morita therapy

Morita therapy a therapy for shinkeishitsu consisting of an initial period of strict and isolated bed rest followed by step-by-step occupational therapy and final reintegration into job and family. A central concept is the attainment of arugamama, an attitude of acceptance toward one’s self and one’s feelings. [Shoma Morita (1874–1938), Japanese psychiatrist]

morning sickness

morning sickness nausea and vomiting experienced by some women during the first months of pregnancy or throughout the entire pregnancy. Although morning sickness usually occurs soon after arising in the morning, some women have the symptoms throughout the day. Also called nausea gravidarum.

morning-after pill

morning-after pill a popular name for postcoital, or emergency, oral contraception. It consists of two doses of a progestin, or a combined formulation of a progestin and an estrogen, taken at spaced intervals no later than 72 hours after intercourse.

morning-glory seeds

morning-glory seeds seeds of the plant Rivea corymbosa, which contain psychoactive agents and have been used as hallucinogens, notably in 16th-century Mexico.

Moro reflex

Moro reflex a reflex in which a newborn infant, when startled, throws out the arms, extends the fingers, and often quickly brings the arms back together as if clutching or embracing. In normal, healthy babies, the Moro reflex disappears during the 1st year. Also called Moro response. See also startle response. [Ernst Moro (1874–1951), German physician]

moron

moron n. an obsolete name for a person with mild mental retardation. [first described by Henry Herbert Goddard]

morpheme

morpheme n. in linguistic analysis, a unit of meaning that cannot be analyzed into smaller such units. For example, the word books is composed of two morphemes, book and the suffix -s signifying a plural noun. See bound morpheme; free morpheme. —morphemic adj.

morphine

morphine n. the primary active ingredient in opium, first synthesized in 1806 and widely used as an analgesic and sedative. It interacts predominantly with the mu opioid receptor. Prolonged administration or abuse can lead to dependence and to withdrawal symptoms on cessation. The substance is 10 times as potent as opium for pain relief. See opioid intoxication; opioid use disorder.

morpho- (morph-)

Sorry, "morpho-morph" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

morphogenesis

morphogenesis n. the development of the form and structure of an organism. —morphogenetic or morphogenic adj.

morphological index

morphological index the index or relationship based on body proportions that describes a particular body build.

morphology

morphology n. 1. the branch of biology concerned with the forms and structures of organisms. 2. the branch of linguistics that investigates the form and structure of words. It is particularly concerned with the regular patterns of inflection and word formation in a language. With syntax, morphology is one of the two traditional subdivisions of grammar. —morphological adj.

morphometrics

morphometrics n. the theory and technique associated with the physical measurement of living organisms and their component parts. Studies of size, shape, and structure are important not only in biology but also in neuropsychology and medical psychology. For example, researchers interested in morphometrics could study the form and structure of the brain in individuals who have various physical or psychological disorders. By contrast, psychometrics specifically focuses on the measurement of psychological phenomena.

morphophilia

morphophilia n. interest in sexual partners whose body characteristics (e.g., height, weight, skin and hair color) are different from one’s own.

morphophoneme

morphophoneme n. an abstract phonological unit used to represent the set of phonemes that constitute the allomorphs of a single morpheme.

morphophonemics

morphophonemics n. a branch of linguistics that analyzes the interaction between morphology and phonology, especially regarding the use of different allomorphs of the same morpheme in different phonological contexts. —morphophonemic adj.

Morris water maze

Morris water maze a device used to test spatial learning in nonhuman animals, consisting of a water-filled tank with a platform hidden underwater. An animal is placed in the water and can escape only by finding and climbing on the hidden platform. Typically, a variety of external cues are provided for spatial reference. The Morris water maze is often used to evaluate the effects of brain lesions or drug manipulations on spatial learning and memory. [devised in 1981 by Richard G. M. Morris, British neuroscientist]

morsicatio buccarum

morsicatio buccarum habitual biting of the inside of the cheeks (buccal mucosa), sometimes causing lesions or the formation of white excess tissue.

morsicatio labiorum

morsicatio labiorum see lip biting.

mort douce

mort douce primarily in literary contexts, a peaceful death (French, literally “sweet death”) in which all tensions are released in a manner reminiscent of the fulfillment of sexual intercourse.

mortality

mortality n. 1. the state or condition of being subject to illness, decline, and death. 2. the death rate in a population.

mortality effect

mortality effect the degree to which circumstances or behavior increase or decrease the incidence of death. For example, a behavioral health researcher could study the mortality effects of a fatty diet and lack of exercise, which could lead to early death from heart disease.

mortality rate

mortality rate a measure of how often death occurs, usually with respect to a specific illness, characteristic, behavior, or population. For example, a researcher could estimate the mortality rate for individuals who have been diagnosed with cancer.

mortality salience

mortality salience awareness of the inevitability of one’s death. According to terror management theory, mortality salience, coupled with death anxiety, is a motivating force behind a diverse set of actions designed to defend oneself or one’s social group when threatened.

morula

morula n. an early stage of embryological development, extending from the first cleavage of the zygote until the blastula is formed by further divisions of daughter cells.

mosaic test

mosaic test a projective technique in which the participant, usually a child, is asked to “make anything you like” out of about 400 pieces of different colors and shapes. Mosaic materials are also used in some intelligence tests.

mosaicism

mosaicism n. a condition of genetic abnormality in which an individual is made up of two or more different cell lines derived from a single zygote. In a typical case, an individual with mosaicism will have some cells with the usual number of chromosomes and others with an extra chromosome.

mossy fiber

mossy fiber any of certain nerve fibers that extend from the dentate gyrus to the hippocampus, where they synapse in area CA3.

most comfortable loudness (MCL)

Sorry, "most-comfortable-loudness-mcl" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mother archetype

mother archetype in Carl Jung’s analytic psychology, the primordial image of the generative and sustaining mother figure that has occurred repeatedly in various cultural concepts and myths since ancient times and is located within the collective unconscious.

mother figure

mother figure 1. a person who occupies the mothering role in relation to a child: a mother surrogate. 2. in psychoanalytic theory, a person onto whom the patient transfers feelings and attitudes that he or she had toward the real mother or the primary caregiver. Also called mother substitute.

mother substitute

mother substitute 1. see mother figure. 2. see mother surrogate.

mother surrogate

mother surrogate a substitute for an individual’s biological mother (e.g., a sister, grandmother, stepmother, adoptive mother), who assumes the responsibilities of that person and may function as a role model and significant attachment figure. Harry Harlow’s classic research demonstrated that young monkeys preferred a mother surrogate covered in cloth to one that was simply a wire frame, even though the latter was the source of food. Also called mother figure; surrogate mother.

motherese

motherese n. the distinctive form of speech used by parents and other caregivers with infants and young children. It is characterized by grammatically simple and phonologically clear utterances, often delivered in a high-pitched sing-song intonation.

mothering

mothering n. the process of nurturing, caring for, and protecting a child by a mother or maternal figure.

Mothers Against Drunk Driving (MADD)

Sorry, "mothers-against-drunk-driving-madd" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

motility

motility n. the capacity for spontaneous, independent movement. —motile adj.

motion aftereffect (MAE)

Sorry, "motion-aftereffect-mae" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

motion agnosia

motion agnosia see akinetopsia.

motion and time study

motion and time study see time and motion study.

motion detection

motion detection the ability to detect movement. Many cells in the visual system act as motion detectors, and some are also sensitive to the direction of movement.

motion economy

motion economy a set of principles for the efficient performance of vocational tasks. Motion economy was developed largely by U.S. engineer Frank Gilbreth (1868–1924) and his wife, U.S. engineer and psychologist Lillian Moller Gilbreth. Its recommendations include simultaneous use of both hands moving in opposite directions; use of continuous, curved movements rather than straight line motions; use of the fewest movements possible; use of such items as jigs and fixtures to relieve hands of unnecessary work as “holding devices”; arrangement of work to permit an easy, natural rhythm; and arrangement of work to avoid long reaches.

motion in limine

motion in limine a formal proposal to a court, usually made before a trial begins (Latin in limine, “threshold”), requesting that certain statements, questions, or evidence not be introduced into the proceedings.

motion parallax

motion parallax the interrelated movements of elements in a scene that can occur when the observer moves relative to the scene. Motion parallax is a depth cue.

motion sickness

motion sickness a type of discomfort marked by nausea, dizziness, headache, pallor, cold sweats, and in some cases vomiting and prostration. The cause is irregular or abnormal motion that disturbs the normal sense of balance maintained by the semicircular canals of the inner ear. The condition may be aggravated or initiated by an emotional disturbance, such as anxiety or grief. Also called kinesia.

motivated forgetting

motivated forgetting a memory lapse motivated by a desire to avoid a disagreeable recollection. It is one of the cognitive mechanisms that have been suggested as a cause of delayed memories of childhood trauma.

motivation

motivation n. 1. the impetus that gives purpose or direction to behavior and operates in humans at a conscious or unconscious level (see unconscious motivation). Motives are frequently divided into (a) physiological, primary, or organic motives, such as hunger, thirst, and need for sleep; and (b) personal, social, or secondary motives, such as affiliation, competition, and individual interests and goals. An important distinction must also be drawn between internal motivating forces and external factors, such as rewards or punishments, that can encourage or discourage certain behaviors. See extrinsic motivation; intrinsic motivation. 2. in conditioning, the variables, collectively, that alter the effectiveness of reinforcers. Compare establishing operation. 3. a person’s willingness to exert physical or mental effort in pursuit of a goal or outcome. See work motivation. 4. the act or process of encouraging others to exert themselves in pursuit of a group or organizational goal. The ability to motivate followers is an important function of leadership. —motivate vb. —motivated adj. —motivational adj.

motivation research

motivation research in consumer psychology, research that uses clinical, intensive, and qualitative approaches to reveal the true motives behind the decisions of individuals to purchase a product. Motivation research is also employed to determine why consumers may refuse to buy a certain product.

motivational enhancement therapy

motivational enhancement therapy a transtheoretical treatment, based on the stages of change, that matches clients to interventions on the basis of individual differences in readiness to change. This treatment was initially applied to substance abuse but has now generalized to other problem behaviors. See also motivational interviewing.

motivational factor

motivational factor any physiological or psychological factor that stimulates, maintains, and directs behavior. Examples are basic physiological needs, interests, and extrinsic rewards.

motivational hierarchy

motivational hierarchy see Maslow’s motivational hierarchy.

motivational interviewing

motivational interviewing a client-centered yet directive approach for facilitating change by helping people to resolve ambivalence and find intrinsic reasons for making needed behavior change. Originally designed for people with substance use disorders, motivational interviewing is now broadly applied in health care, psychotherapy, correctional, and counseling settings. It is particularly applicable when low intrinsic motivation for change is an obstacle. Rather than advocating for and suggesting methods for change, this approach seeks to elicit the client’s own goals, values, and motivation for change and to negotiate appropriate methods for achieving it. See also motivational enhancement therapy. [developed by U.S. clinical psychologist William R. Miller (1947– ) and South African-born British clinical psychologist Stephen Rollnick]

motivational selectivity

motivational selectivity an explanation for the different ways that an event or object may be perceived by different people based on the influence of individual motives on cognitive processes. See selective perception.

motivational style

motivational style the characteristic manner in which an individual seeks or finds the motivation to perform a task. Categories are based on individual differences in motivation, including but not limited to intrinsic–extrinsic motivation, mastery orientation, and competitiveness. The notion of motivational styles is particularly used in education, business, and sport to help people recognize both strengths and weaknesses and develop strategies to improve learning and performance.

motivators

motivators pl. n. in the two-factor theory of work motivation proposed by U.S. clinical psychologist Frederick Herzberg (1923–2000), those aspects of the working situation that can increase satisfaction and motivation. Motivators involve the work itself rather than the work context and are increased by means of job enrichment and vertical loading (see job enlargement). Compare hygiene factors.

motive

motive n. 1. a specific physiological or psychological state of arousal that directs an organism’s energies toward a goal. See motivation. 2. a reason offered as an explanation for or cause of an individual’s behavior.

motoneuron

motoneuron n. see motor neuron.

motor

motor adj. involving, producing, or referring to muscular movements.

motor agraphia

motor agraphia a writing disorder resulting from impairment of muscular coordination in the hand.

motor amimia

motor amimia see amimia.

motor amusia

motor amusia see amusia.

motor aphasia

motor aphasia a form of nonfluent aphasia characterized by difficulty in producing articulate speech. An example is Broca’s aphasia, for which motor aphasia is often used as a synonym. See also aphemia.

motor aprosodia

motor aprosodia an inability to produce the emotional inflections of language, that is, to express the normal rhythm, pitch, and “melody” of speech. This is most often due to damage in the right frontal lobe of the brain. Compare sensory aprosodia.

motor area

motor area an area of the motor cortex that, when stimulated, produces movements of skeletal muscles in various parts of the body. It has somatotopic organization, with individual neurons controlling a specific movement direction of an associated body part that might involve coordinated action of several muscles. Also called Brodmann’s area 4.

motor behavior

motor behavior 1. aspects of human movement that include motor control, motor development, and motor learning. 2. see motor function.

motor control

motor control the influence of neurophysiological factors on human movement.

motor conversion symptoms

motor conversion symptoms one of two types of symptoms of conversion disorder, the other being sensory conversion symptoms. Examples of motor conversion symptoms include impaired coordination and balance, paralysis or weakness confined to a specific area of the body, difficulty in swallowing, aphonia (loss of voice), and urinary retention.

motor coordination

motor coordination the cooperative action of reflexive (or involuntary) and voluntary movements to carry out complex activities.

motor cortex

motor cortex the region of the frontal lobe of the brain responsible for the control of voluntary movement. It is divided into two parts. The primary motor cortex, or motor area, is the main source of neurons in the corticospinal tract. The secondary (or nonprimary) motor cortex, made up of the premotor area and the supplementary motor area, is specialized for planning upcoming movements and learning new movements. Lesions in the primary motor cortex due to stroke or traumatic injury usually cause initial paralysis that may improve to a condition involving weakness and poor muscle tone. Lesions in the secondary motor cortex usually cause disruptions in motor planning for complex movements (see apraxia). Also called motor strip.

motor development

motor development the changes in motor skills that occur over an entire lifespan, which reflect the development and deterioration of muscular coordination and control and are also affected by personal characteristics, the environment, and interactions of these two factors.

motor disorder

motor disorder loss of the ability to perform simple or complex acts or skills because of temporary or permanent damage to tissues in the premotor or motor areas of the central nervous system. The cause of the damage may be a congenital or inherited defect, injury, surgical excision, or a psychochemical factor.

motor disturbance

motor disturbance any disruption of motor behavior, such as hyperactivity, retarded activity, automatism, repetitive movements, rigid posture, grimacing, or tics.

motor dominance

motor dominance the controlling influence of one cerebral hemisphere shown in motor activity, such as writing or throwing a ball.

motor end plate

motor end plate see end plate.

motor equivalence

motor equivalence the ability to use different movements, produced by either the same or different parts of the body, to perform a task under different conditions. For example, the task of writing one’s name may be performed (a) on paper, with a pen held in the hand, by moving the fingers and wrist; (b) on a blackboard, with chalk held in the hand, by moving the arm; or (c) in the sand, using a toe, by moving the leg.

motor evoked potential

motor evoked potential a type of evoked potential associated with motor neurons and motor cortex. For example, activity in spinal motor neurons may be studied by directly stimulating motor areas in the brain (see transcranial magnetic stimulation) and observing the evoked potential in the spinal cord. Compare sensory evoked potential.

motor function

motor function any activity that results from stimulation of motor neurons, including glandular activity as well as reflexes and voluntary and involuntary muscle contractions. Also called motor behavior.

motor homunculus

motor homunculus a figurative representation, in distorted human form, of the somatotopic organization of the motor cortex as originally mapped by U.S.-born Canadian neurosurgeon Wilder Penfield (1891–1976). Within this mapping, the size of the brain region associated with a body part reflects the complexity of the activities carried out with that part of the body rather than its actual size. Compare sensory homunculus.

motor imitation

motor imitation the ability, particularly striking in infants and children, to imitate movements, facial expressions, and so forth after viewing them and without practice.

motor impersistence

motor impersistence a neurologically based inability to sustain a simple act or posture, such as keeping the mouth open or turning the head, for longer than a few seconds. [identified in 1956 by Canadian physician Charles Miller Fisher (1913–2012)]

motor learning

motor learning the process of acquiring and perfecting motor skills and movements, either simple acts or complex sequences of movements, which comes about through varying types of practice, experience, or other learning situations. Motor learning results in muscle memory, whereby the acquired motor skill can be performed without conscious effort, as in playing a musical instrument, climbing stairs, or riding a bike. See motor development. See also three-stage theory.

motor memory

motor memory knowledge of motor skills: the capacity to remember previously executed movements, such as the steps of a dance or the actions involved in tying one’s shoes. Compare verbal memory; visual memory.

motor milestones

motor milestones the significant achievements in motor development that occur during an infant’s first 2 years. Although individual children vary, on average infants will (a) support their head while prone at 3 months; (b) support their head in other positions at 4 months; (c) sit with props at 5 months; (d) sit supported by their hands and reach with one hand at 6 months; (e) pick up small items, using thumb opposition, and stand if holding onto a railing at 8 months; (f) creep, pull to a standing position, and take side steps while holding onto a support at 10 months; (g) walk alone, throw a ball, and walk backwards, sideways, upstairs, and downstairs with assistance at 16 months; and (h) run and walk up and down steps easily or with minimal assistance at 24 months. See also developmental sequence.

motor neglect

motor neglect underutilization of or failure to use motor functions on one side of the body despite the presence of normal strength, reflexes, and sensibility. It results from damage to various cerebral structures, including the thalamus and frontal and parietal lobes.

motor nerve

motor nerve any nerve that terminates in a muscle or gland, conveying impulses from the brain or spinal cord.

motor neuron

motor neuron a neuron whose axon connects directly to muscle fibers. Because motor neurons are the final stage of output from the nervous system and are the only means of stimulating muscle fibers, they are known as the final common path. There are two types: lower motor neurons (or alpha motor neurons), found in the cranial nerves and the anterior horn of the spinal cord and that are responsible for muscle contraction; and upper motor neurons (or gamma motor neurons), found in the corticospinal tract and that modulate the sensitivity of muscle spindles, thus influencing activity of the lower motor neurons. Also called motoneuron.

motor neuron disease

motor neuron disease any one of a group of degenerative disorders of the lower motor neurons or both the lower and upper motor neurons, marked by progressive weakness and wasting of skeletal muscles and paralysis. This group of disorders includes several forms, but—especially in the United States—the term often is applied specifically to amyotrophic lateral sclerosis.

motor neuron lesion

motor neuron lesion any damage to a motor neuron, particularly if it involves the cell body.

motor neuron pool

motor neuron pool a collection of motor neurons whose axons all connect to the same muscle, although the motor neurons may be scattered through a few levels of the spinal cord.

motor overflow

motor overflow a condition in which intentional motor behavior in one muscle group is accompanied by unintentional movement in another muscle group as a result of neurological dysfunction. For instance, while performing a fine motor task with the right hand, the left hand may move as well. Also called synkinesia; synkinesis.

motor pathway

motor pathway a neural pathway that originates in the brain or brainstem and descends down the spinal cord to control the motor neurons. The motor pathways can control posture, reflexes, and muscle tone, as well as the conscious voluntary movements associated with the motor system.

motor planning

motor planning the ability of the brain to conceive, organize, and carry out a sequence of unfamiliar actions.

motor primacy theory

motor primacy theory the concept that body mechanisms associated with motor nerve functions develop before sensory nerve mechanisms.

motor program

motor program a stored representation, resulting from motor planning and refined through practice, that is used to produce a coordinated movement. Motor programs store the accumulated experience underlying skill at a task. See also generalized motor program.

motor root

motor root see ventral root.

Motor scale

Motor scale see Bayley Scales of Infant and Toddler Development.

motor set

motor set preparatory adjustments or readiness to make a certain response or begin an activity, such as prompted by the call “Ready, Set, Go!” at the start of a foot race.

motor speech disorder

motor speech disorder any of several communication disorders arising from inaccurate production of speech sounds because of lack of strength or coordination of the muscles involved in speaking, as occurs in cerebellar ataxia or Parkinson’s disease.

motor strip

motor strip see motor cortex.

motor system

motor system the complex of skeletal muscles, neural connections with muscle tissues, and structures of the central nervous system associated with motor functions. Also called neuromuscular system.

motor tension

motor tension a state of muscle tension in which the individual is restless and tires easily. This symptom is associated with generalized anxiety disorder.

motor test

motor test any test designed to measure motor skills, ranging from gross motor to fine motor manipulation.

motor theory of speech perception

motor theory of speech perception the view that speech perception relies on the processes that are used in speech production, such that listeners interpret a spoken message by nonconsciously computing what motor operations would be required to produce that sequence of sounds. The theory was advanced as an explanation of categorical perception in the processing of speech sounds. [proposed by U.S. psychologist Alvin M. Liberman (1917–2000)]

motor tract

motor tract any bundle of nerve fibers that convey signals from the higher centers of the brain to the spinal cord.

motor unit

motor unit a group of muscle fibers that respond collectively and simultaneously because they are connected by nerve endings to a single motor neuron.

mouches volantes

mouches volantes see muscae volitantes.

mountain-climber’s syndrome (mountain sickness)

Sorry, "mountain-climbers-syndrome-mountain-sickness" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mourning

mourning n. the process of feeling or expressing grief following the death of a loved one, or the period during which this occurs. It typically involves apathy and dejection, loss of interest in the outside world, and diminution in activity and initiative. These reactions are similar to depression but are less persistent and are not considered pathological. Other mourning reactions may include anger (e.g., toward the deceased for dying); a sense of relief (e.g., that the deceased is no longer suffering); anxiety about the repercussions of losing someone upon whom the bereaved may have depended; and physical signs (e.g., fatigue, loss of appetite). See also bereavement.

mouse-movement adapter

mouse-movement adapter an adaptive device for a computer mouse that is used to control the movement of the pointer on the screen. The device is designed for use by individuals with motor disabilities who are not able to manipulate a standard computer mouse manually.

mouthstick

mouthstick n. for individuals with mobility impairments, a type of physical extension device consisting of a piece fitting into the mouth of the user that is attached to an extension with a tip that may press against, grasp, pull, or point to an object. It may be used, for example, to press an elevator button, turn on a light switch, turn a page in a book, or type on a keyboard.

movement

movement n. a brief, unitary activity of a muscle or body part. A movement is less complex than an act.

movement chaining

movement chaining the generation of complex movement sequences whereby the occurrence of, or feedback from, each movement in the sequence acts as the stimulus to initiate the next. [originally described by Charles Scott Sherrington in relation to sequences of reflexes]

movement disorder

movement disorder any abnormality in motor processes, relating primarily to posture, coordination, or locomotion. See also medication-induced movement disorder.

movement illusion

movement illusion an illusion that an object is in motion when it is not.

movement learning

movement learning see motor learning; response learning.

movement perspective

movement perspective a visual illusion produced by the relative distance of moving objects. For example, a nearby bird flying at 50 kmh (c. 30 mph) may appear to be traveling faster than a jet airliner in the distant sky moving at 960 kmh (nearly 600 mph).

movement sense

movement sense see kinesthesis.

movement therapy

movement therapy a therapeutic technique in which individuals use rhythmic exercises and bodily movements to achieve greater body awareness and social interaction and enhance their psychological and physical functioning. See also dance therapy.

movement-sensitive retinal cells

movement-sensitive retinal cells cells, most commonly found in the retinas of lower animals, that respond to various specific movements across the visual field. Examples include the bug-detector cells of amphibians, which respond best to small, dark, moving spots, and cells that adapt quickly to objects moving in a particular direction.

moving-edge detector

moving-edge detector any of the cells in the visual system that respond best to a dark–light border moved through the receptive field. A particular speed and direction of movement may be required to elicit the optimum response from a moving-edge detector. See also feature detector.

moving-window technique

moving-window technique in studies of reading, an experimental technique in which the words on a page are covered up except for a limited number that can be viewed through a “window,” which moves forward through the text at a set rate.

Mowat sensor

Mowat sensor an aid to ambulation for individuals with visual impairment. It is a lightweight, handheld device, similar to a flashlight, that detects objects by sending out brief pulses of high-frequency sound (ultrasound). The device vibrates when it detects an object, and users can tell how close they are to the object by the rate of vibration. The device ignores everything but the closest object within the beam.

Mozart effect

Mozart effect a temporary increase in the affect or performance of research participants on tasks involving spatial–temporal reasoning after listening to the music of Austrian composer Wolfgang Amadeus Mozart (1756–1791). More generally, the term refers to the possibility that listening to certain types of music enhances inherent cognitive functioning. Apart from the neurological research on this effect, some experts propose an arousal theory perspective, such that listening to music heightens emotional levels that correspond to higher performance on intelligence tests. The notion of the Mozart effect has entered into popular culture to carry the as-yet-unsupported suggestion that early childhood exposure to classical music benefits mental development or intelligence.

mPOA

mPOA abbreviation for medial preoptic area.

MPS

MPS 1. abbreviation for mucopolysaccharidosis. 2. abbreviation for myofascial pain syndrome. See chronic myofascial pain.

MPTP

MPTP n. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine: a byproduct of heroin synthesis that is used experimentally to induce symptoms of Parkinson’s disease in laboratory animals. It was discovered accidentally in 1976 when it was synthesized and injected by a recreational drug user who was attempting to produce an analog of meperidine. This individual developed acute symptoms of Parkinson’s disease, as did other users of the drug. Autopsy revealed massive degeneration of dopamine-containing neurons in the nigrostriatal tract. MPTP is not in itself neurotoxic (damaging to nerve tissue), but it is converted to the methylphenylpyridinium ion (MPP+), a potent neurotoxin at dopaminergic neurons, by the enzyme monoamine oxidase B.

MR

MR abbreviation for mental retardation.

MRH

MRH abbreviation for Müllerian regression hormone. See Müllerian-inhibiting hormone.

MRI

MRI abbreviation for magnetic resonance imaging.

mRNA

mRNA abbreviation for messenger RNA.

MRT

MRT abbreviation for Modified Rhyme Test.

MS

MS abbreviation for multiple sclerosis. MS symbol for mean square.

MSE

MSE abbreviation for mental status examination. MSE symbol for mean square error.

MSH

MSH abbreviation for melanocyte-stimulating hormone.

MSH2

MSH2 a germ-line mutation located on the short arm of chromosome 2 and associated with hereditary nonpolyposis colorectal cancer (HNPCC). See also MLH1.

MSI

MSI abbreviation for magnetic source imaging. See magnetoencephalography.

MSIS

MSIS abbreviation for multistate information system.

MSLT

MSLT abbreviation for Multiple Sleep Latency Test.

MSP

MSP abbreviation for Münchausen syndrome by proxy.

MSQ

MSQ abbreviation for Minnesota Satisfaction Questionnaire.

MSR

MSR symbol for mean square residual.

MST

MST abbreviation for McCarthy Screening Test.

MSUD

MSUD abbreviation for maple-syrup urine disease.

MT (middle temporal)

Sorry, "mt-middle-temporal" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

MTcA

MTcA abbreviation for mixed transcortical aphasia.

MTG

MTG abbreviation for middle temporal gyrus.

MTMM

MTMM 1. abbreviation for multitrait–multimethod matrix. 2. abbreviation for multitrait–multimethod model.

mu

mu (symbol: μ) see population mean.

mu opioid receptor

mu opioid receptor see opioid receptor.

mucocutaneous skin

mucocutaneous skin the hairless skin of the lips. This type of skin is also found at other junctions between the inside and outside of the body (e.g., the nasal and anal orifices).

mucopolysaccharidosis (MPS)

Sorry, "mucopolysaccharidosis-mps" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mucous colitis

mucous colitis see irritable bowel syndrome.

mucous ophthalmia

mucous ophthalmia see ophthalmia.

muina

muina n. see bilis.

muliebrity

muliebrity n. the state or condition of being a woman (from Latin mulier, “woman”) or the qualities considered to be characteristic of women.

Müller cell

Müller cell an elongated nonneuronal central nervous system cell (glia) that traverses and supports all the layers of the retina, collecting light and directing it toward the photoreceptors. A component of the inner nuclear layer, these cells were originally called Müller fibers because of their thin, stretched shape. [Heinrich Müller (1820–1864), German anatomist]

Müller-Lyer illusion

Müller-Lyer illusion a geometric illusion in which a difference is perceived in the length of a line depending on whether arrowheads at either end are pointing toward each other or away from each other. Also called arrowhead illusion. [first described in 1889 by Franz Müller-Lyer (1857–1916), German psychiatrist and sociologist]

Müller–Urban process

Müller–Urban process a procedure for calculating the difference threshold for data obtained using the method of constant stimuli. It is based on the assumption that the best measure of the threshold is the median of the best fitting ogive (S-shaped function) for the distribution. [Georg Elias Müller; Frank M. Urban, 20th-century U.S. psychologist]

Müller–Urban weights

Müller–Urban weights a set of numerical modifiers used in determining the best value of h (the measure of precision of process) by fitting observations to the normal curve. Also called Urban’s weights. [Georg Elias Müller and Frank M. Urban]

Müllerian duct

Müllerian duct either of a pair of ducts that occur in a mammalian embryo and develop into female reproductive structures (fallopian tubes, uterus, and upper vagina) if testes are not present in the embryo. Compare Wolffian duct. [Johannes Müller]

Müllerian mimicry

Müllerian mimicry a form of mimicry in which two or more species, each of which is toxic or potentially harmful, have similar body shape or coloration. For predators, a single experience with a member of one of these species can lead to learned avoidance of all similar-looking animals, conferring protection on all the mimetic species. [Johann Friedrich Theodor Müller (1822–1897), German zoologist]

Müllerian-inhibiting hormone (MIH)

Sorry, "mullerian-inhibiting-hormone-mih" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

multa loca tenens principle

multa loca tenens principle a rule stating that if a drug can substitute for or mimic one action of a natural physiological agent, it may be able to simulate other natural functions as well. Because of such multiple effects, the administered drug may compete for receptors, enzymes, and other physiological targets. [Latin, “holding (or substituting at) many places”)]

multi-infarct dementia

multi-infarct dementia see vascular dementia.

multiattribute utility analysis

multiattribute utility analysis a method of using the ratings of judges to quantify the value of complex alternatives or choices. In program evaluation, dimensions relevant to outcomes of different programs are ranked and then weighted in terms of their comparative importance, and each program is scored on all value dimensions. This form of analysis enables comparisons of different programs to be made.

multiaxial classification

multiaxial classification a system of classifying mental disorders according to several categories of factors (e.g., social and cultural influences) as well as clinical symptoms. See DSM–IV–TR; DSM–5.

multicollinearity

multicollinearity n. in multiple regression, the state that occurs when several independent variables are extremely highly interrelated, making it difficult to determine separate effects on the dependent variable. For example, if a researcher includes predictors of self-esteem, self-efficacy, and self-concept in an analysis with a dependent variable of achievement, multicollinearity most likely will be present.

multicultural education

multicultural education a progressive approach to education that emphasizes social justice, equality in education, and understanding and awareness of the traditions and language of other cultures and nationalities. Multicultural programs involve two or more ethnic or cultural groups and are designed to help participants define their own ethnic or cultural identity and to appreciate that of others. The purpose is to promote inclusiveness and cultural pluralism in society.

multicultural psychology

multicultural psychology an extension of general psychology that recognizes that multiple aspects of identity influence a person’s worldview, including race, ethnicity, language, sexual orientation, gender, age, disability, class status, education, religious or spiritual orientation, and other cultural dimensions, and that both universal and culture-specific phenomena should be taken into consideration when psychologists are helping clients, training students, advocating for social change and justice, and conducting research.

multicultural therapy

multicultural therapy 1. any form of psychotherapy that takes into account not only the racial and ethnic diversity of clients but also their diversity in spirituality, sexual orientation, ability and disability, and social class and socioeconomic status; the potential cultural bias (e.g., racism, sexism) of the practitioner; the history of oppressed and marginalized groups; acculturation issues for immigrant clients; and the politics of power as they affect clients. 2. any form of therapy that assesses, understands, and evaluates a client’s behavior in the multiplicity of cultural contexts (e.g., ethnic, national, demographic, social, economic) in which that behavior was learned and is displayed.

multiculturalism

multiculturalism n. 1. the quality or condition of a society in which different ethnic and cultural groups have equal status and access to power but each maintains its own identity, characteristics, and mores. 2. the promotion or celebration of cultural diversity within a society. Also called cultural pluralism. Compare cultural monism. —multicultural adj.

multidetermination

multidetermination n. the interaction of several different factors in the etiology of a disorder (e.g., biological, psychological, environmental). —multidetermined adj.

multidetermined behavior

multidetermined behavior the concept that human behavior is influenced by the interaction of multiple factors, past and present. In general, the major influences are genetic, environmental, physiological, and psychological.

Multidimensional Scale for Rating Psychiatric Patients

Multidimensional Scale for Rating Psychiatric Patients see Inpatient Multidimensional Psychiatric Scale.

multidimensional scaling

multidimensional scaling (MDS) a scaling method that represents perceived similarities among stimuli by arranging similar stimuli in spatial proximity to one another, while disparate stimuli are represented far apart from one another. Multidimensional scaling is an alternative to factor analysis for dealing with large matrices of data or stimuli.

multidimensionality

multidimensionality n. 1. the quality of a construct that cannot be adequately described by measuring a single trait or attribute. 2. the quality of a scale, test, or so forth that is capable of measuring more than one dimension of a construct. For example, a psychometrician may be interested in investigating the multidimensionality of a new scale to measure cognitive functioning. Compare unidimensionality. —multidimensional adj.

multidisciplinary approach

multidisciplinary approach see interdisciplinary approach.

multidisciplinary team

multidisciplinary team a group of individuals, each with expertise in a different field of study, who are brought together to examine a subject area or to assist people.

multifactorial

multifactorial adj. consisting or arising out of several factors, variables, or causes.

multifactorial inheritance

multifactorial inheritance inheritance of a trait, such as height or predisposition to a certain disease, that is determined not by a single gene but by many different genes acting cumulatively. Such traits show continuous, rather than discrete, variation among the members of a given population and are often significantly influenced by environmental factors, such as nutritional status. Also called polygenic inheritance.

multifactorial model

multifactorial model a model of inheritance positing that the genetic and environmental causes of a trait constitute a single continuous variable, the liability, and that if that liability is exceeded, the trait will manifest itself.

multiform layer

multiform layer see cortical layers.

multifunctional antidepressant

multifunctional antidepressant an antidepressant that acts primarily via more than one major neurotransmitter system. The term is often applied to the SNRIs (e.g., venlafaxine), which inhibit the reuptake of both norepinephrine and serotonin, to distinguish them from the SSRIs (selective serotonin reuptake inhibitors). Also called dual-action antidepressant; mixed-function antidepressant.

multigenerational transmission

multigenerational transmission the passing on of psychological problems, primarily anxiety, over several generations through family relationships. A central concept in family systems theory, the principal process involves the nonconscious passing on of a higher level of anxiety, which overrides adaptive thinking and behavior, to members in each succeeding generation. Interventions to change this transmission involve charting family relationships and coaching individuals on how to interact with targeted relatives, usually those who are lowest in anxiety and who function at the most adaptive level. [developed by U.S. psychiatrist Murray Bowen (1913–1990)]

multigenerational trauma

multigenerational trauma see intergenerational trauma.

multigravida

multigravida n. a woman who has had two or more pregnancies. Compare primigravida.

multilevel model

multilevel model see hierarchical linear model.

Multilingual Aphasia Examination (MAE)

Sorry, "multilingual-aphasia-examination-mae" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

multilingualism

multilingualism n. the sociolinguistic situation in which several languages are used within the same community, usually resulting from geographical, economic, political, or militaristic interactions. Typically, the various languages differ in status and serve different social functions. See diglossia.

multimethod approach

multimethod approach a design that uses more than one procedure for measuring the main characteristic or construct of interest. For example, a researcher could use a multimethod approach to understanding relationship satisfaction by simultaneously collecting data from a survey, asking one or both of the partners to give their own self-report, and systematically observing the degree of relationship satisfaction. See also multitrait–multimethod model.

multimethod–multitrait model

multimethod–multitrait model see multitrait–multimethod model.

multimodal distribution

multimodal distribution a set of data in which there is more than one mode or score that occurs most frequently. For example, the ages of a sample of college students would form a multimodal distribution if the largest number of people are either 18, 19, or 20 years old, with the remaining individuals aged 17 or 21 through 70. See also bimodal distribution; unimodal distribution.

multimodal therapy (MMT)

Sorry, "multimodal-therapy-mmt" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

multimodal treatment

multimodal treatment a manner of treating a disease, disorder, or syndrome by simultaneously applying several different methods, often from different disciplines or traditions.

multinomial

multinomial adj. describing a measurement that can have more than two categories or outcomes. For example, a professor assigning grades of A, B, C, D, or F to students in his or her course is making a multinomial decision, whereas assigning grades of pass or fail would be a binomial decision.

multinomial distribution

multinomial distribution a probability distribution that describes the theoretical distribution of n objects sampled at random from a population of k kinds of things with regard to the number of each of the kinds that appears in the sample. By contrast, a binomial distribution involves just two variables, categories, or objects.

multinormal distribution

multinormal distribution see multivariate normal distribution.

multiparous

multiparous adj. 1. describing a woman (a multipara) who has had two or more pregnancies resulting in live births. Compare primiparous. 2. giving birth to more than one offspring at a time. —multiparity n.

multipayer system

multipayer system see all-payer system.

multiphilia

multiphilia n. interest in multiple, short-term sexual relationships, with no desire for long-term relationships or commitment.

multiple baseline design

multiple baseline design an experimental approach in which two or more behaviors are assessed to determine their initial, stable expression (i.e., baseline) and then an intervention or manipulation is applied to one of the behaviors while the others are unaffected. After a period, the manipulation is then applied to the next behavior while the remaining behaviors are unaltered, and so forth until the experimental manipulation has been applied in sequential fashion to all of the behaviors in the design. In successively administering a manipulation to different behaviors after initial behaviors have been recorded, a multiple baseline design allows for inferences about the effect of the intervention.

multiple causation

multiple causation the view that events, including behaviors, seldom result from single causes but instead from multiple causes working in complex combinations. Multiple causation contrasts with simple causation and, often, with linear causation.

multiple classification

multiple classification the ability to classify items in terms of more than one dimension simultaneously, such as shape and color. According to Piagetian theory, this ability is not achieved until the concrete operational stage.

multiple comparison test

multiple comparison test any of various statistical procedures used to follow up on a significant result from an analysis of variance by determining which groups in particular differ in their mean values. Examples include Duncan’s multiple range test, the Fisher least significant difference test, the REGWQ test, the Scheffé test, and Tukey’s honestly significant difference test. See also post hoc comparison.

multiple comparisons

multiple comparisons a set of comparisons made between samples to identify significant differences among their mean values. Multiple comparisons are generally done in a post hoc manner (i.e., are unplanned) in order to keep the Type I error rate controlled at a prespecified level. Also called multiple contrasts.

multiple correlation coefficient

multiple correlation coefficient (symbol: R) a numerical index of the degree of relationship between a particular variable and two or more other variables. Its value ranges from −1 to +1, with the former indicating a strong negative relationship and the latter a strong positive relationship. Also called multiple R.

multiple correlation coefficient squared

multiple correlation coefficient squared see coefficient of multiple determination.

multiple cutoff model of selection

multiple cutoff model of selection in personnel selection, a model in which an applicant for a job must meet a minimum score on each of several selection instruments (i.e., tests and inventories) in order to be hired. Unlike the multiple hurdle model of selection, the multiple cutoff procedure does not require applicants to take and pass the selection instruments in any particular order.

multiple delusions

multiple delusions concurrent delusions, not necessarily interconnected.

multiple determination

multiple determination see overdetermination.

multiple discriminant analysis

multiple discriminant analysis (MDA) a multivariate statistical procedure for examining the relationship between a set of more than two categories representing an outcome variable and a set of predictor variables. It often is used to verify that the predictors (e.g., family history, self-esteem, number of sleeping hours) are accurately classifying individuals into the appropriate categories of the outcome variable (diagnosis of depression). Also called multiple classification analysis (MCA).

multiple drafts hypothesis

multiple drafts hypothesis the theory that conscious perception occurs not in a specific location in the brain but rather through many approximations (drafts) of sensory input that are widely distributed over the sensory cortex. [proposed by U.S. philosopher Daniel C. Dennett (1942– ) and Austrian-born U.S. neurologist Marcel Kinsbourne (1931– )]

multiple family therapy

multiple family therapy a form of group therapy in which two or more family members meet with two or more therapists at once. See also cotherapy.

multiple hurdle model of selection

multiple hurdle model of selection in personnel selection, a model in which applicants for a job are required to pass each of a series of selection instruments (i.e., tests and inventories) before they are evaluated on the next instrument. The number of applicants is therefore reduced at each “hurdle.” See also banding.

multiple imputation

multiple imputation a method for addressing missing data in which several possible simulated values are inserted into a data set to replace omitted values, and then the mean and standard deviation of the set are calculated to arrive at an estimate to substitute for the missing value. Multiple imputation is considered less biased than other missing values procedures, such as listwise deletion, pairwise deletion, and single imputation.

multiple linear regression

multiple linear regression see multiple regression.

multiple marital therapy

multiple marital therapy a form of therapy in which each marital partner is treated independently by individual therapists. The two therapists may meet privately to discuss their clients, and sessions involving all four parties or a combination of the parties may be held. See also conjoint therapy.

multiple mating

multiple mating in animal behavior, a strategy used by females to prevent certainty of paternity in males and as a mate-selection mechanism. A female mammal might mate with most males in her group, thus giving each male a stake in helping to protect the female and her young. Multiple mating is a form of cryptic female choice if the female can control which male mates with her at the time when conception is most likely.

multiple monitored electroconvulsive treatment (MMECT)

Sorry, "multiple-monitored-electroconvulsive-treatment-mmect" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

multiple orgasm

multiple orgasm in women, the occurrence of more than one orgasm, without a resolution phase (see sexual-response cycle) separating the orgasms. Studies have estimated that as many as 30% of women experience this. Male multiple orgasm does not occur, because further arousal and response are not possible during the refractory phase following male orgasm. However, some men do carefully monitor and control their arousal and may experience the first elements of an orgasm, without ejaculation, more than once before having a complete orgasm, with ejaculation.

multiple personality disorder

multiple personality disorder see dissociative identity disorder.

multiple R

multiple R see multiple correlation coefficient.

multiple range test

multiple range test see Duncan’s multiple range test.

multiple regression

multiple regression a statistical technique for examining the linear relationship between a continuous dependent variable and a set of two or more independent variables. It is often used to predict a single outcome variable from a set of predictor variables. For example, an educational psychology researcher could use multiple regression to predict college achievement (e.g., grade point average) from the variables of high school grade point average, Scholastic Assessment Test (SAT) reading score, SAT mathematics score, and SAT writing score. When a single predictor and a single outcome are involved the process is known as linear regression. Also called multiple linear regression.

multiple regression model of selection

multiple regression model of selection a statistically based model of personnel selection in which the applicant is measured on each of several predictors and these scores are weighted to reflect the goodness of fit between the predictor and performance on a given job criterion. The model assumes that the predictors are linearly related to the job criteria and that they are additive and can compensate for one another.

multiple reinforcement schedule

multiple reinforcement schedule a compound schedule of reinforcement in which two or more schedules alternate and each schedule is associated with a different exteroceptive stimulus. For example, under a multiple fixed-interval extinction schedule, a tone could be present while the fixed-interval schedule is in effect and absent when extinction is in effect.

multiple relationship

multiple relationship see dual relationship.

multiple roles in persuasion

multiple roles in persuasion a postulate in the elaboration-likelihood model holding that variables can influence persuasion in one or more of five possible roles. When elaboration is likely to be low, a variable can influence persuasion by possibly serving as a peripheral cue. When situational and dispositional factors do not cause elaboration to be extremely high or low, a variable can influence persuasion by determining the amount of elaboration. When elaboration is likely to be high, a variable can serve as an argument if it is directly relevant to evaluating the attitude object, as a biasing factor in elaboration, or as a self-validation factor in elaboration.

multiple sclerosis (MS)

Sorry, "multiple-sclerosis-ms" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

multiple selves

multiple selves a psychoanalytic concept of the self as composed of many different self-states with different affective, perceptual, and cognitive features. In normal development, the self-states are thought to be sufficiently compatible to allow for internal conflicts of wishes and desires within the person. In pathological development, or as a result of trauma, the self-states are thought to become defensively dissociated from each other, sometimes resulting in dissociative identity disorder. Also called multiple self-states.

Multiple Sleep Latency Test (MSLT)

Sorry, "multiple-sleep-latency-test-mslt" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

multiple trace hypothesis

multiple trace hypothesis the hypothesis that when a stimulus is presented on multiple occasions, each occasion creates an entirely new record in memory rather than strengthening or otherwise updating an already existing record.

multiple-aptitude test

multiple-aptitude test a battery of separate tests designed to measure a wide range of relatively independent functions and to yield a profile of a person’s abilities in different areas, as contrasted with a single global IQ. Different batteries measure different patterns of abilities. An example is the battery comprising the Differential Aptitude Tests, primarily for use in educational and vocational counseling.

multiple-choice experiment

multiple-choice experiment an experiment in which a participant decides which of several possible choices is correct, usually on the basis of a specific cue that must be learned.

multiple-choice question

multiple-choice question see fixed-alternative question.

multiple-impact therapy

multiple-impact therapy a treatment method in which a group of mental health professionals works with a client family during an intensive, limited period.

multiple-intelligences theory

multiple-intelligences theory the idea that intelligence is made up of eight distinct categories: linguistic, musical, bodily-kinesthetic, logical-mathematical, spatial, naturalist, intrapersonal, and interpersonal. [proposed in 1983 by U.S. psychologist Howard Gardner (1943– )]

multiple-resource model

multiple-resource model a model that views attention as comprising many pools of resources, each pool being specific to one stimulus modality or type of response. Different tasks place varying demands on different resources, and performance suffers less if two tasks draw on different resource pools than if they draw on the same pool. For example, talking while riding a bicycle presents fewer problems than trying to have two conversations at once. See multiple-task performance. Compare unitary-resource model.

multiple-role playing

multiple-role playing a management development technique involving group role play. A large group is broken up into smaller groups, each of which comprises three people sitting in one row and the three people sitting directly behind them. Each six-person group is then given the same problem, with each member assigned one of six roles in the decision-making process. The solutions derived by each group are then reported to the entire body. See also business game; case method; conference method; scenario analysis.

multiple-spike recording

multiple-spike recording the recording and analyzing of potentials from rapidly firing neurons using microelectrodes connected to computer equipment.

multiple-task performance

multiple-task performance a scenario in which a person must perform two or more tasks either simultaneously or contemporaneously. Success will depend on the degree to which the person can divide his or her attentional resources between tasks. See multiple-resource model; unitary-resource model. See also performance-operating characteristic.

multiplex

multiplex n. a method of coding information that enables two or more messages or data streams to be transmitted simultaneously over the same communication channel.

multiplication rule

multiplication rule a rule stating that the joint probability of two independent events occurring together or in succession is equal to the probability of the first event times the probability of the second event. For example, the multiplication rule would indicate that the probability of drawing a heart followed by the probability of drawing a spade is equal to 13/52 × 13/52 = .25 × .25 = .0625. Also called and rule; multiplication law; multiplicative law. Compare addition rule.

multiplicative model

multiplicative model a description of the effect of two or more predictor variables on an outcome variable that allows for interaction effects among the predictors. This is in contrast to an additive model, which sums the individual effects of several predictors on an outcome. For example, a health researcher could use a multiplicative model to examine the interaction effect of number of cigarettes smoked per day and length of smoking habit on the onset of cancer; the results might be compared to those obtained from an additive model that examines the separate effects of amount of cigarettes and length of a smoking habit on cancer onset.

multiplicity-versus-unity dimension

multiplicity-versus-unity dimension the degree to which a work of art is characterized by complexity (multiplicity) versus harmony (unity). Arousal in the viewer is heightened by complexity factors and lowered by elements of harmony. Multiplicity in art is sometimes held to be associated with historical periods of political or economic insecurity, when tensions are reflected in “deformation” of art styles.

multipolar neuron

multipolar neuron a neuron that has many dendrites and a single axon extending from the cell body. Also called multipolar cell. Compare bipolar neuron; unipolar neuron.

multisensory learning

multisensory learning learning in which the material of interest is presented through several sensory modalities (e.g., seeing, hearing, touching) rather than through only one modality.

multisensory method

multisensory method an approach to teaching reading and spelling that incorporates the visual, auditory, kinesthetic, and tactile modalities. See Fernald method.

multiskilled (multiskill)

Sorry, "multiskilled-multiskill" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

multistage sampling

multistage sampling a technique in which samples are drawn first from higher order groupings (e.g., states) and then from successively lower level groupings (e.g., counties within states, towns within counties) in order to avoid the necessity of having a sampling frame for the entire population. That is, if subunits within a selected unit give similar results, one can select and measure a sample of the subunits in any chosen unit to avoid uneconomically measuring all of them. When two grouping sets are involved, the process is also known as two-stage sampling, when three sets are involved it is also called three-stage sampling, and so on.

multistage theory

multistage theory any theory concerning a process that posits a series of steps or stages operating serially to accomplish that particular process.

multistate information system (MSIS)

Sorry, "multistate-information-system-msis" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

multistore model of memory

multistore model of memory any theory hypothesizing that information can move through and be retained in any of several memory storage systems, usually of a short-term and a long-term variety. The first to propose a multistore model were U.S. cognitive psychologists Richard C. Atkinson and Richard M. Shiffrin (1942– ) in 1968 (see information-processing model), with other researchers subsequently proposing their own such models as well. Also called storage-and-transfer model of memory. See dual-store model of memory; modal model of memory.

multisynaptic arc

multisynaptic arc see polysynaptic arc.

multitrait–multimethod matrix (MTMM)

Sorry, "multitrait-multimethod-matrix-mtmm" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

multitrait–multimethod model (MTMM)

Sorry, "multitrait-multimethod-model-mtmm" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

multivariate

multivariate adj. consisting of or otherwise involving a number of distinct variables. For example, a multivariate study of ability could involve multiple measures of intelligence and achievement. Compare univariate. See also bivariate.

multivariate analysis

multivariate analysis 1. a set of statistical procedures for studying the relationships between one or more predictors and several outcome or dependent variables. Examples include canonical correlation analysis for assessing the relationships among two sets of variables; factor analysis for assessing the relationships among a large set of measures and a small set of underlying factors; multivariate analysis of variance and multivariate analysis of covariance for assessing potential group differences on several dependent variables; and structural equation modeling, which examines a theoretically based pattern of relationships among multiple independent, dependent, and even mediating variables. Also called multivariate statistics. Compare univariate analysis. 2. more generally, any procedure for understanding any large set of variables, whether dependent or independent.

multivariate analysis of covariance (MANCOVA)

Sorry, "multivariate-analysis-of-covariance-mancova" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

multivariate analysis of variance (MANOVA)

Sorry, "multivariate-analysis-of-variance-manova" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

multivariate distribution

multivariate distribution the arrangement of scores obtained on several variables. For example, a health researcher may want to examine the multivariate distribution of scores on level of exercise, cholesterol level, and blood pressure in a sample of individuals at risk for heart disease. Compare univariate distribution.

multivariate normal distribution

multivariate normal distribution a pattern of values on several variables in which a graph of the data forms a bell-shaped normal distribution. Evidence for a multivariate normal distribution may be obtained using a quantile–quantile plot. If the plot shows a series of points along a diagonal line, indicating a lack of any discrepant scores (i.e., any multivariate outliers), then the data have a multivariate normal distribution. Also called multinormal distribution.

multivariate normality

multivariate normality the situation in which the values for a set of variables have an even distribution, with most scores falling in the middle of the range and a smaller number of high and low scores. In other words, a set of scores demonstrating multivariate normality follows a multivariate normal distribution and lacks outliers or extreme scores.

multivariate research

multivariate research a study conducted to simultaneously assess the relationships among multiple dependent variables and independent variables. Compare univariate research.

multivariate statistics

multivariate statistics see multivariate analysis.

multivariate test

multivariate test any of various statistical procedures involving two or more outcome or dependent variables. An example is the multivariate analysis of variance, which extends the analysis of variance examining one dependent variable to include additional dependent variables. Factor analysis and multiple regression sometimes are considered multivariate tests as well, even though the former involves a single set of variables that are not necessarily independent or dependent and the latter allows for multiple independent variables but only one outcome.

mum effect

mum effect see upward communication.

Münchausen syndrome

Münchausen syndrome a severe and chronic form of factitious disorder characterized by repeated and elaborate fabrication of clinically convincing physical symptoms and a false medical and social history (see pseudologia fantastica). Other features are peregrination and recurrent hospitalization, and there may be multiple scars from previous (unnecessary) investigative surgery. The patient’s motivation is a psychological need to assume the sick role. See also pathomimicry. [Baron Karl Friedrich Hieronymus von Münchhausen (1720–1797), German soldier-adventurer famous for his tall tales but not for having the disorder itself]

Münchausen syndrome by proxy (MSP)

Sorry, "munchausen-syndrome-by-proxy-msp" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

mundane realism

mundane realism the extent to which an experimental situation resembles a real-life situation or event. See also experimental realism.

Munsell color system

Munsell color system a method of color notation devised for use mainly in science, industry, and technology. The system uses numerical designations for hue, saturation, and brightness of color for accurate identification and specification. See color value. [Albert H. Munsell (1858–1918), U.S. artist]

murder

murder n. the unlawful killing of one person by another, particularly when the act involves premeditation. See also homicide.

murder–suicide

murder–suicide the intentional killing of another person followed by the suicide of the killer. See also extended suicide.

muscae volitantes

muscae volitantes particles or specks seen as floating before the eyes. Also called mouches volantes. [Latin, literally, “flying flies”]

muscarine

muscarine n. a toxic alkaloid, isolated from fly agaric (Amanita muscaria) and some other fungi, that stimulates certain types of acetylcholine receptors (the muscarinic receptors) in smooth muscle, cardiac muscle, endocrine glands, and the central nervous system. See also nicotine. —muscarinic adj.

muscarinic receptor (mAChR)

Sorry, "muscarinic-receptor-machr" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

muscimol

muscimol n. see fly agaric; GABA agonist; ibotenic acid.

muscle

muscle n. contractile tissue that generates force and moves parts of the body. The main types of muscle are smooth muscle, skeletal muscle, and cardiac muscle.

muscle action potential

muscle action potential a wave of electric potential that sweeps across a muscle when it is stimulated. See action potential.

muscle contraction

muscle contraction a shortening of the muscle fibers in response to electrical stimulation from a motor neuron by which a muscle exerts force on the tissues to which it is attached. This stimulation initiates an electrochemical sequence in which myosin filaments, powered by ATP (adenosine triphosphate), detach from a nearby actin filament, swing forward to reattach further along the actin filament, and then swing back causing the actin and myosin filaments to slide in opposite directions. When this process is repeated in many muscle fibers, the overall muscle becomes shorter but thicker. See isometric contraction; isotonic contraction.

muscle dysmorphia

muscle dysmorphia a form of body dysmorphia characterized by chronic dissatisfaction with one’s muscularity and the perception that one’s body is inadequate and undesirable, although objective observers would disagree with such an assessment. This condition often leads to excessive exercising, steroid abuse, and eating disorders. It is typically found in males, especially bodybuilders. Also called bigorexia; reverse anorexia.

muscle fiber

muscle fiber a microscopic strand of muscle tissue that functions as a molecular machine converting chemical energy into force. Thousands of muscle fibers are linked by connective tissue into a muscle. Each fiber is, in turn, composed of millions of longitudinally aligned protein filaments. It is the interaction of actin and myosin protein molecules (sometimes together referred to as actomyosin) in these filaments that creates muscle contraction.

muscle memory

muscle memory see motor learning.

muscle relaxant

muscle relaxant any of various drugs used in the management of spasms of skeletal muscle generally resulting from mechanical injury, stroke, cerebral palsy, or multiple sclerosis. Most act on the central nervous system or its associated structures to reduce muscle tone and spontaneous activity. Although the precise mode of action varies with the drug, muscle relaxants generally act by depressing spinal reflexes without loss of consciousness. Common muscle relaxants include benzodiazepines, baclofen, dantrolene, and botulinum toxin. Others used for localized muscle spasms include carisoprodol, cyclobenzaprine, methocarbamol, and orphenadrine.

muscle relaxation

muscle relaxation the release of tension from muscle; that is, the alteration of the state of the muscle on a continuum from full contraction to flaccidity.

muscle sensation

muscle sensation a kinesthetic awareness of movements and tensions in muscles, tendons, and joints. See kinesthetic feedback.

muscle spindle

muscle spindle a receptor that lies within skeletal muscle, parallel to the main contractile muscle fibers, that sends impulses to the central nervous system when the muscle is stretched.

muscle tonus

muscle tonus see tonus.

muscle twitch

muscle twitch a small, sudden, and brief involuntary contraction of a muscle, as opposed to sustained contraction.

muscle-contraction headache

muscle-contraction headache a headache arising from increased muscle tension, frequently in the neck. Also called muscle-tension headache.

muscle-tension gradient

muscle-tension gradient the rate of change of muscle tension during performance of a task. It is measured by electromyography.

muscular dystrophy (MD)

Sorry, "muscular-dystrophy-md" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

muscular rigidity

muscular rigidity stiffness in muscles that is resistant to changes in position. Individuals may misinterpret this symptom as weakness, but the condition usually occurs in the presence of normal strength. See cogwheel rigidity; lead-pipe rigidity.

muscular type

muscular type a constitutional type characterized by dominance of the muscular and locomotor systems over other body systems (see Rostan types). It corresponds to the athletic type in Kretschmer typology.

musculocutaneous nerve

musculocutaneous nerve a nerve that innervates the muscles of the upper arm and cutaneous receptors of the lateral forearm.

musculoskeletal disorder

musculoskeletal disorder any disease, injury, or significant impairment of muscles, bones, joints, and supporting connective (soft) tissues.

musculoskeletal system

musculoskeletal system the system of skeletal muscles and bones that generally function together to move the body and its parts and to maintain its general form.

music therapy

music therapy the use of music as an adjunct to the treatment or rehabilitation of individuals to enhance their psychological, physical, cognitive, or social functioning. Music therapy involves singing, writing music, performing music, listening to music, and lyric analysis, among other techniques.

musical intelligence

musical intelligence in the multiple-intelligences theory, the skills used in writing, playing, remembering, and understanding music.

musical interval

musical interval the pitch or frequency spacing between two sounds. Two sounds that are an octave apart (i.e., with an interval of an octave) have a 2:1 ratio of their fundamental frequencies. See also cent.

musician’s cramp

musician’s cramp a type of occupational cramp experienced by musicians, usually in the arm or hand, that prevents them from performing. The condition may be due to electrolyte imbalance. See also repetitive strain injury.

musicogenic epilepsy

musicogenic epilepsy a type of reflex epilepsy in which seizures are precipitated by music.

mussitation

mussitation n. unintelligible muttering, or moving the lips without producing speech.

musturbation

musturbation n. the belief by some individuals that they must absolutely meet often perfectionist goals in order to achieve success, approval, or comfort. Cognitive and behavioral therapies may be useful in bringing awareness and perspective to such maladaptive cognitions. See also rational emotive behavior therapy. [defined by Albert Ellis]

musty

musty adj. denoting one of the seven classes of odorants in the stereochemical smell theory.

mutation

mutation n. a permanent change in the genetic material of an organism. It may consist of an alteration to the number or arrangement of chromosomes (a chromosomal mutation) or a change in the composition of DNA, generally affecting only one or a few bases in a particular gene (a point mutation). Mutations can occur spontaneously, but many are due to exposure to agents (mutagens) that significantly increase the rate of mutation; these include X-rays and other forms of radiation and certain chemicals. A mutation occurring in a body cell (i.e., a somatic mutation) cannot be inherited, whereas a mutation in a reproductive cell producing ova or spermatozoa (i.e., a germ-line mutation) can be transmitted to an individual’s offspring. Most mutations either have no discernible effect or have a deleterious effect; however, a tiny minority are beneficial and thus give an individual and his or her descendants a selective advantage. Genetic testing of families or groups at high risk for single-gene disorders ascertains the presence or absence of mutations responsible for these disorders.

mutilation

mutilation n. 1. the destruction or removal of a limb or an essential part of the body. 2. a destructive act causing a disfiguring injury to the body. See also self-mutilation.

mutism

mutism n. lack or absence of speaking due to physical or psychogenic factors. The condition may result from a structural defect in the organs necessary for speech, congenital or early deafness in which an individual’s failure to hear spoken words inhibits the development of speech, neurological damage or disorder, psychological disorders (e.g., conversion disorder, catatonic schizophrenia), or severe emotional disturbance (e.g., extreme anger). The condition may also be voluntary, as in monastic vows of silence or the decision to speak only to selected individuals. See also akinetic mutism; alalia; selective mutism; stupor.

muttering delirium

muttering delirium a type of delirium in which an individual’s speech is marked by low utterances, slurring, iteration, dysarthria, perseveration, or any combination of these. Typically, the individual’s movements are dominated by restlessness and trembling.

mutual exclusivity assumption

mutual exclusivity assumption in language development, the tendency of children to suppose that an object has only one category label. If a child already knows a label for a whole object and hears a novel label applied, the assumption of mutual exclusivity will block the possibility that the novel label refers to the whole object. The child will then consider other possible referents of the novel label, such as a part of the object. Compare taxonomic assumption; whole object assumption.

mutual gaze

mutual gaze see eye contact.

mutual help

mutual help a form of self-help that is not professionally guided and that involves joining with others similar to oneself to explore ways to cope with life situations and problems. Mutual help can occur in person, by telephone, or through the Internet.

mutual masturbation

mutual masturbation 1. sexual activity in which two individuals stimulate each other’s genitals at the same time for the purpose of sexual gratification. This is more properly considered a type of petting behavior, as masturbation is defined as self-stimulation. 2. sexual activity in which two or more individuals stimulate their own genitals while jointly viewing erotic materials.

mutual pretense

mutual pretense an interaction pattern in which all participants try to act as if they are unaware of the most crucial facts in a situation (e.g., a situation in which one of the participants is terminally ill). This pattern is often regarded by therapists and researchers as an anxiety-driven strategy that inhibits communication, increases tension, and leads to missed opportunities for meaningful mutual support. [first described in Awareness of Dying (1965) by U.S. sociologists Barney G. Glaser (1930– ) and Anselm L. Strauss (1916–1996)]

mutual reward theory

mutual reward theory see reward theory.

mutual storytelling technique

mutual storytelling technique a play therapy technique for communicating metaphorically with children. The therapist instructs a child to tell a fictional story that has a moral or lesson and then assesses the feelings and conflicts communicated in the story. The therapist then makes up a similar story but attempts to introduce a more adaptive resolution to the conflict in the story. [developed by U.S. psychiatrist Richard A. Gardner (1931–2003)]

mutual support group

mutual support group a group composed of individuals who meet on a regular basis to help one another cope with a shared life problem. This term is sometimes used by researchers and practitioners instead of the traditional term self-help group, as it emphasizes the mutual, interdependent nature of self-help group processes.

mutualism

mutualism n. an interaction in which two species live together in close association, to the mutual benefit of both. See also symbiosis. Compare commensalism; parasitism.

mutuality

mutuality n. 1. the tendency of relationship partners to think of themselves as members of a dyadic relationship rather than as distinct individuals. As close relationships, particularly romantic ones, develop over time, partners display increasing levels of mutuality, which may influence their affect, cognition, and behavior. For example, when mutuality is high, people tend to think of their partners’ characteristics and resources as their own. 2. in interdependence theory, the tendency of partners to depend equally on each others’ behavior for the attainment of desirable outcomes. In asymmetric relationships, one partner plays a larger role than the other in determining what outcomes each partner receives, but in relationships characterized by mutuality, their power and influence are approximately equivalent.

mutually exclusive events

mutually exclusive events 1. two or more events that have no common elements. See also disjoint sets. 2. in probability theory, two or more events that cannot co-occur: The occurrence of one precludes the simultaneous or subsequent occurrence of the other(s). For example, the alternatives “heads” and “tails” in a single toss of a coin are mutually exclusive events.

my-

Sorry, "my" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

myasthenia

myasthenia n. muscular weakness or lack of muscular endurance.

myasthenia gravis

myasthenia gravis an autoimmune disorder (see autoimmunity) in which the body produces antibodies against acetylcholine receptors, causing faulty transmission of nerve impulses at neuromuscular junctions. Affected muscles—initially those of the face and neck—are easily fatigued and may become paralyzed temporarily (e.g., muscles involved in eating may fail to function normally toward the end of a meal, speech may become slurred after a period of talking). The disease is progressive, eventually affecting muscles throughout the body.

mydriasis

mydriasis n. excessive dilation (widening) of the pupil of the eye caused by anticholinergic drugs (e.g., atropine and scopolamine) acting on muscarinic receptors or by opioid withdrawal. —mydriatic adj., n.

myel-

Sorry, "myel" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

myelencephalon

myelencephalon n. see medulla oblongata.

myelin

myelin n. the substance that forms the insulating sheath around the axons of many neurons. It consists mainly of phospholipids, with additional myelin proteins, and accounts for the whitish color of white matter.

myelin sheath

myelin sheath the insulating layer around many axons that increases the speed of conduction of nerve impulses. It consists of myelin and is laid down by glia, which wrap themselves around adjacent axons. The myelin sheath is interrupted by small gaps, called nodes of Ranvier, which are spaced about every millimeter along the axon. Also called medullary sheath.

myelinated fiber

myelinated fiber a nerve fiber that is covered by a myelin sheath. The insulating properties of the myelin sheath enable myelinated fibers to conduct nerve impulses much faster than nonmyelinated fibers (see saltatory conduction).

myelination

myelination n. the formation and development of a myelin sheath around the axon of a neuron, which is effected by neuroglia, such as Schwann cells. Researchers look to anomalies in this process to explain some forms of severe mental illness (e.g., schizophrenia). Also called axonal myelination; medullation; myelinization.

myelitis

myelitis n. inflammation of the spinal cord.

myelo- (myel-)

Sorry, "myelo-myel" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

myeloarchitecture

myeloarchitecture n. the development and distribution of the fiber processes of the nerve cells of the brain, particularly the myelinated fibers. See also cortical layers.

myelocele

myelocele n. protrusion of the spinal cord through an abnormal opening in the vertebral column, as found in spina bifida.

myelomeningocele

myelomeningocele n. see meningomyelocele.

myenteric plexus

myenteric plexus a network of nerve fibers and neuron cell bodies located between the inner and outer muscle layers of the digestive tract, including the esophagus, stomach, and intestines. Together with other enteric plexuses, it controls the responses of the digestive tract.

Myers–Briggs Type Indicator (MBTI)

Sorry, "myers-briggs-type-indicator-mbti" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

myesthesia

myesthesia n. the muscle sense; that is, the sensation felt in muscle contractions and the awareness of movement in muscles and joints. See also kinesthesis.

myo- (my-)

Sorry, "myo-my" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

myocardial infarction

myocardial infarction see infarction.

myoclonic

myoclonic adj. of, relating to, or characterized by myoclonus.

myoclonic epilepsy

myoclonic epilepsy epilepsy characterized by myoclonic seizures or myoclonus in conjunction with other types of seizure. Also called myoclonus epilepsy.

myoclonic movements

myoclonic movements movements characterized by rapid, involuntary muscle jerks.

myoclonic seizure

myoclonic seizure a rare type of generalized seizure characterized by rapid, involuntary muscle jerks.

myoclonus

myoclonus n. rapid, involuntary contraction of a muscle or group of muscles. This may occur normally, as when a limb or other part of the body suddenly jerks while falling asleep (see nocturnal myoclonus), or abnormally, as in Creutzfeldt–Jakob disease and other neurological disorders.

myoclonus epilepsy

myoclonus epilepsy see myoclonic epilepsy.

myoelectric prothesis

myoelectric prothesis an artificial limb (see prosthesis), such as a myoelectric arm, that can be manipulated by nerve impulses generated by voluntary muscle movements. The nerve impulses are received by an electronic transducer that amplifies and converts them into appropriate movements of the prosthesis through tiny electric motors.

myofascial pain syndrome (MPS)

Sorry, "myofascial-pain-syndrome-mps" is not in the Dictionary of Psychology. Please report to APA if you believe this is an error.

myography

myography n. a technique that utilizes apparatus to record aspects of muscle activity. Some devices record the small electric potential that accompanies contraction of the muscle fibers. A myograph is an instrument that records the extent, force, or duration of isotonic contractions or the tension and duration of isometric contractions. A myogram is a graphic record of the velocity and intensity of muscle contractions. —myographic adj.

myoneural junction

myoneural junction see neuromuscular junction.

myopathy

myopathy n. any disease or disorder of the muscles, hereditary or acquired. The term is usually qualified by an adjective that specifies the type of myopathy or its cause. For example, acute alcoholic myopathy and hereditary myopathy suggest a cause, whereas ocular myopathy defines the affected area as the muscles that control eye movements, and neuromyopathy refers to a disorder of the nerves and muscles combined.

myopia

myopia n. nearsightedness, a refractive error due to an abnormally long eye: The retinal image is blurred because the focal point of one or both eyes lies in front of, rather than on, the retina. Specific types include chromic myopia, marked by defective color perception of distant objects; progressive myopia, a gradual loss of accommodation for distant vision associated with aging; and prodromal myopia, in which accommodation changes permit a return of normal sightedness after a period of myopia. Compare emmetropia; hyperopia.

myosin

myosin n. see muscle fiber.

myosis

myosis n. see miosis.

myositis

myositis n. inflammation of a muscle.

myotatic reflex

myotatic reflex see stretch reflex.

myotonia

myotonia n. increased tone and contractility of a muscle, with slow or delayed relaxation. —myotonic adj.

myotonic disorder

myotonic disorder any disease, generally inherited, in which voluntary muscles show increased tone and contractility but relax slowly and with great difficulty. The condition often affects the muscles of the hands or is manifested by general muscle stiffness.

myotonic muscular dystrophy

myotonic muscular dystrophy a type of muscular dystrophy marked by increased muscle tone and contractility (myotonia) and muscle wasting, most noticeably in the face and hands, and often accompanied by cataracts and cardiac abnormalities. It is an autosomal dominant disorder (see dominant allele) that is usually first noted in adolescence or early adulthood, although age of onset can vary. Also called dystrophia myotonica; Steinert’s disease.

myriachit

myriachit n. a culture-bound syndrome found in Siberian populations. Similar to latah, it is characterized by indiscriminate, apparently uncontrolled imitations of the actions of other people encountered by the individual. Also called ikota; irkunii; menkeiti; olan. See also imu; jumping Frenchmen of Maine syndrome.

Mysoline

Mysoline n. a trade name for primidone.

mysophilia

mysophilia n. a pathological interest in dirt or filth, often with a desire to be unclean or in contact with dirty objects. Mysophilia may be expressed as a paraphilia in which the person is sexually aroused by a dirty partner.

mystic union

mystic union the feeling of spiritual identification with God, nature, or the universe as a whole. See Buddhism; oceanic feeling; transcendental meditation; yoga; Zen therapy.

mystical participation

mystical participation a mode of engagement or type of mental activity in which the boundaries between the natural and the spiritual, and between oneself and one’s environment, are either overcome or not established in the first place. The term was introduced by French philosopher and ethnologist Lucien Levy-Bruhl (1857–1939), who held that mystical participation is a characteristic of so-called primitive cultures.

mysticism

mysticism n. 1. the view that there are real sources of knowledge and truth other than sensory experience and rational deduction. It is held that such knowledge comes through inspiration, revelation, or other experiences that are not strictly sensory, although there may be a sensory component. A common implication is that such knowledge cannot readily be shared with or conveyed to others but must be individually achieved. Mysticism thus carries a connotation of subjectivism. 2. the belief that an immediate knowledge of, or union with, the divine can be achieved through personal religious experience. Accounts of mystical experiences in the writings of various spiritual traditions typically describe a state of intense, trancelike contemplation in which a sense of profound insight is accompanied by feelings of ecstatic self-surrender. —mystic n., adj. —mystical adj.

Mytelase

Mytelase n. a trade name for ambenomium.

mythology

mythology n. 1. a body of traditional stories (myths) associated with the early history of a particular culture. Such stories generally involve supernatural beings and events and often seek to explain particular natural or cultural phenomena (e.g., the cycle of the seasons, a specific custom) in terms of their supposed origins. Myths are often distinguished from legends as having little or no basis in historical events. 2. the study of myths. Sigmund Freud compared myths to dreams, which contain hidden meanings, and believed they throw unique light on the cultures from which they stem, and in some instances, as in the myth of Oedipus, on human nature in general. 3. in Carl Jung’s analytic psychology, primordial images, or archetypes, that are stored in the collective unconscious. —mythological adj.

mythomania

mythomania n. 1. a tendency to elaborate, exaggerate, and tell lies, including reports of imagined experiences, often involving self-deception. See also factitious disorder; pathological lying. 2. an abnormal interest in myths, in which the individual may believe fantasy to be reality, and a tendency to fabricate incredible stories. Also called pseudologia fantastica.

myxedema

myxedema n. a metabolic disorder that develops in adulthood due to a deficiency of thyroid hormone (see hypothyroidism). The condition is characterized by subnormal heart rate, circulation, body temperature, and most other metabolic activities. Affected individuals tend to be fatigued, listless, and overweight but usually respond to administration of thyroxine. —myxedemic adj.

MZ twins

MZ twins abbreviation for monozygotic twins.

Psychology Terms Starting With 'M'