Electrophysiological correlates of processing facial attractiveness and its influence on cooperative behavior

The present study investigated the temporal features of processing facial attractiveness, and its influence on the subsequent cooperative behavior. Event-related potentials (ERPs) were recorded for both face stimuli (attractive or unattractive faces) and feedback stimuli (loss or gain) while participants performed a modified trust game task, in which participants decided whether to cooperate with fictional partners (attractive or unattractive faces) for a chance to earn monetary rewards; feedback (loss or gain) were presented after their decisions. The behavioral results showed that participants were more likely to cooperate with the attractive partners than with the unattractive partners. The ERP analysis for face stimuli showed that a smaller P2 amplitude was elicited by attractive faces compared to unattractive faces. In addition, attractive faces elicited larger N2 and smaller late positive component (LPC) amplitudes than unattractive faces. More interestingly, a larger feedback related negativity (FRN) was elicited within the attractive face condition compared with the unattractive face condition. Therefore, our findings demonstrate that the discrimination of attractive and unattractive faces occurs at the early P2 stage, reflecting automatic processing of facial attractiveness. Moreover, the present study further demonstrates that facial attractiveness facilitates cooperative behavior, and that FRN elicited by outcome stimuli might be used as an index of how people judge and predict another's behavior in a social game.