THE MOTIVATIONAL DEFICIT IN DEPRESSION: VALUE VS. INCENTIVE.

摘要

Previous studies have elaborated on the motivational deficit found in depressive disorders. The present experiment attempted to avoid confounding factors by measuring separately the value and incentive properties of motivation as they pertain to depression. Theories of depression tested included those stating depressed people undervalue rewards or are overly averse to punishers. Also investigated were theories which state depression results from faulty expectations of rewards and punishers. Male and female undergraduate students (n = 96) were divided into a depressed group, a psychiatric control group, and a normal control group based on specific criteria. Measures of reward and punisher value as well as expectancy data were gathered for each group. Rational zero point scaling was used to obtain ratio scales of undergraduates' reward values and punisher aversions. Choice frequency and expectancy data were analyzed using analysis of variance techniques. Results showed that depressives as a group neither undervalued all rewards, nor were they overly averse to all punishers. These findings are directly inconsistent with the loss of reinforcer effectiveness hypothesis proposed by Costello. Depressives did not undervalue social rewards but did appear overly averse to social publishers. This provides partial support for the theories of Lewinsohn and Layne. Consistent with the cognitive theories of Beck and Seligman, depressives expected fewer rewards and more punishers than did the control groups. Based on the expectancy data, it was proposed that depressives lack a self-serving expectancy bias which prevents a functional increase in their level of motivation.