Monitoring of one's own and other's performance during social interactions is crucial to efficiently adapt our behavior and to optimize task performance. In the present study we investigated to what extent social factors can modulate behavioral adjustments in performance. For this purpose, participants executed a flanker task and alternated either with a computer program or with a human partner in cooperative and competitive contexts. Modulations in reaction times (RTs) (post-error slowing) and error rates (post-error accuracy) after error observation were analyzed. The results revealed that these behavioral measures were differently affected by the social manipulations. Post-error slowing was modulated by the social context (cooperation vs...