Competition modulates the effects of social comparison on ERP responses during face processing.

Little is known about the effect of prior social performance feedback on face processing. Our previous study explored how equal and unequal social comparison-related outcomes modulate event-related potential (ERP) responses to subsequently-presented faces, where interests between oneself and others were independent (noncompetitive situations). Here, we aimed to extend this investigation by assessing how different unequal social comparison-related outcomes affect face processing under noncompetitive and competitive situations (i.e., a conflict of interest exists between the self and others). To address this issue, 39 participants were exposed with self-related and social comparison-related outcomes, categorized as positive or negative, after performing an attentional task with peers. Rewards and punishments depended on social comparison-related outcomes in the competition condition and on self-related outcomes in the noncompetition condition. ERP results showed that social comparison-related outcomes influenced P100 responses to faces in the self-positive condition. More notably, the effects on N170 responses observed in the noncompetition condition was absent in the competition condition. There was an effect on LPP responses only in the competition and self-negative condition. These findings suggest that social comparison-related outcomes influence early face processing irrespective of competition, while competition subsequently disrupts this processing but later, enhances depending on self-related outcomes.