Find over 25,000 psychological definitions


confluence model

a controversial theory that intelligence of siblings is correlated with family size. According to this model, average intelligence generally declines as the number of children in a family increases. Intelligence is also held to decline with birth order. The one exception is an only child, whose intelligence suffers because he or she does not have an older sibling to serve as a teacher. However, many variables (e.g., spacing of children) could affect and reverse such generalizations. [proposed in 1975 by Robert B. Zajonc and Greg Markus]

Browse dictionary by letter

a b c d e f g h i j k l m n o p q r s t u v w x y z

Psychology term of the day

March 11th 2025

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.