Abstract
Social comparison is an important process that affects an individual’s self-assessment and subjective well-being. Previous studies have observed abnormal social comparison tendencies among depressed individuals, which may account for their social avoidance behavior. In this study, we asked participants to finish a simple gambling task with a friend, during which they could observe the outcome of their choice and that of their friend’s simultaneously (which were pseudorandomly determined). Behavioral measures and event-related potentials (ERP) elicited by outcome presentation (including the P2, feedback-related negativity, and P3 components) were recorded and analyzed. The whole sample consisted of a depression tendency (DT) group and a non-depressive control group, which were divided according to individual scores on Symptom Checklist-90 and Self-Rating Depression Scale. Compared to the controls, the DT group was generally in a more negative mood both before and after the experiment, as demonstrated by Positive Affect and Negative Affect Scale data. No between-group difference was detected regarding participants’ relationship closeness with their friend (as measured by the Inclusion of Other in the Self Scale) or self-reported outcome satisfaction. In contrast, the influence of depression on the P2 and FRN was significant. Specifically, the P2 elicited by self-win was larger in the controls than the DT group; also, it was sensitive to friend’s outcome in the DT group but not the control group. Finally, the FRN was sensitive to self-outcome in the DT group only when their friends had won. In our opinion, these results reveal that depression has abnormal neural processing patterns in the early attention and middle evaluation stages of social comparison. This model possibly be related to depression-related self-cognitive vulnerability (such as low self-esteem): compared to non-depressive ones, depressed individuals’ self-assessment is more susceptible to other people’s status, indicating more vulnerable self-esteem.