The effects of depression and cognitive vulnerability to depression on judgments of similarity between self and other

The present research was conducted to investigate the effects of mild levels of depression, and cognitive vulnerability to depression, on people's perceptions of their similarity to others. Depression level was assessed using the Beck Depression Inventory, and cognitive vulnerability was measured with the Dysfunctional Attitude Scale. Subjects rated their similarity to others on a 7-point scale and also generated a list of attributes thought to typify the average other person. In terms of similarity judgments, individuals perceived themselves to be less similar to others as depression level increased. Furthermore, and also as predicted, only individuals scoring high on the vulnerability measure exhibited this pattern. Given the consistently positive view of others expressed by all subjects, this latter finding suggests that vulnerable individuals saw themselves as increasingly distinctive with respect to their own negative attributes, as depression level increased. This social comparison interpretation is consistent with previous research indicating that vulnerable individuals change from a focus on self-referent positive traits when nondepressed to a focus on negative traits when depressed. This pattern is also identified as a possible contributor to the social isolation and interpersonal difficulties characteristic of depression.