E-ISSN : 2733-4538
Two control experiments based on the theory of signal detectability were conducted in an effort to determine whether the illusion of control among nondepressed individuals and depressive realism among depressed individuals are phenomena occurring in the perceptual level or the judgmental level. The results were not clear for the subjects who appeared to be severely depressed on BDI. However, for those who appeared to be nondepressed or mildly depressed on BDI, the degree of depression was negatively related with d' but not at all with β. Moreover, the difference in d' between the mildly depressed and the nondepressed subjects was due to the fact that the mildly depressed subjects committed a larger number of judgmental errors than did the nondepressed subjects in the situations where the task was actually controllable. In other words, the difference in d' between the mildly depressed and nondepressed subjects was resulted from the difference in hit rate between the two groups. The two groups did not differ from each other in false alarm rate. This result casts some doubt to the existence of the phenomena so called "illusion of control" and "depressive realism". Individual differences in attentiveness to and interest in control tasks were discussed as possible explanations for the negative relation between BDI score and d'.