Depression: Motivational deficit versus social manipulation

Abstract

Two hypotheses of depression were tested. One states that depression is a motivational deficit, where motivation equals a person's expectancy of an outcome multiplied by the value of that outcome. An alternative hypothesis states that depression is a social manipulation aimed at eliciting sympathy from others. To test these hypotheses, 60 undergraduates were divided into a depressed, a psychiatric control, and a normal control group. All undergraduates rated a list of outcomes in terms of their expectancies and again in terms of their valuations. Half of each group completed their ratings in a public setting, half in a private setting. A series of 3(groups) ×2(settings) analyses of variance supported none of the social-manipulation predictions: Depressives never exhibited more severe pathology in the public setting than in the private setting. On the other hand, all of the predictions generated by the motivational deficit hypothesis were supported: Depressives exhibited lower reward expectancies, higher punisher expectancies, and lower reward motivation than both control groups, suggesting that these motivational deficits are not the result of psychopathology in general. Further, depressives tended to undervalue rewards and to be underaverse to punishers.