confounded effects

the indivisible effects of two or more predictor or independent variables on a single response or dependent variable. That is, the unique influence of one predictor cannot be separated out from that of the others. For example, assume a researcher is examining the effectiveness of a hunger-reduction pill for weight loss. If some of the participants receiving the pill discover they are part of the treatment group and concurrently adopt better eating habits and increase their exercise levels, these additional healthy activities will also affect weight loss. Since those in the control group (receiving a placebo sugar pill) are not engaging in these same supplemental activities, effects of eating habits, exercise levels, and the actual treatment will have become confounded.

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Psychology term of the day

March 11th 2025

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.