Disappearance of self-serving bias: Reward positivity reflects performance monitoring modulated by responsibility attribution in a two-person cooperative task

Abstract Performance monitoring plays a virtual role in individual reinforcement learning. However, it remains unclear how responsibility attribution modulates the individual monitoring process in a social cooperative context. In the present study, 46 participants received feedback on the team's monetary outcome, teammate performance, and their own performance sequentially for a two-person task. Using event-related potential (ERP), we analyze brain activity in response to performance monitoring during team and self feedback, indexed according to reward positivity (RewP). Overall, the participants reported a modest tendency towards causal attribution in terms of taking more responsibility for negative rather than positive team-feedback, thus indicating an opposite pattern to the so-called self-serving bias phenomenon. Based on post-experiment responsibility attribution, participants were further divided into a ‘Modest’ group (N = 23) who reported more responsibility for team failure than success, and an ‘Ordinary’ group (N = 23) who made comparable attribution irrespective of team outcome. The ERP results show that there is no difference in RewP amplitudes between the two groups when the participants were processing the team's monetary feedback. However, the observed RewP amplitudes are notably different in the Modest group when processing self-performance feedback at different levels of responsibility attribution. These findings demonstrate that neural activity during performance monitoring does not differ between the two groups. However, using different responsibility attribution tendencies does affect brain activity during individual performance monitoring. The observed RewP effect sheds light on the automatic and implicit evaluation of one's own performance in a social cooperative context.