Reward and punishment effects on error processing and conflict control.

Recently, positive affect has been reported to reduce cognitive conflicts and adaptations related to conflict control. van Steenbergen et al. (2009) proposed that the aversive quality of conflicts drives short-term adaptations following a conflict. They reasoned that monetary gain and its positive emotional consequences might counteract the aversive quality of conflict and hence reduce subsequent adaptations. In two experiments, we combined Simon-type conflicts with monetary gains and losses in between trials and analyzed event-related brain potentials. In Experiment 1, gains and losses occurred randomly between trials as a lottery, whereas in Experiment 2 gains and losses were contingent upon performance, either rewarding the 25% fastest responses or penalizing the 25% slowest responses. In Experiment 1, conflict adaptation was completely unaffected by gains or losses; contrary to predictions, in Experiment 2, conflict adaptation in reward blocks was more pronounced after a gain. In Experiment 2 we also investigated the error-related negativity (ERN) - a brain signal proposed to be related to performance monitoring. The ERN and behavioral post-error slowing were enlarged in the context of reward; therefore, reward increases error adaptation, possibly by enhancing the subjective value of errors. In conclusion, affective modulations of conflict adaptations seem to be much more limited than previously asserted and adaptive mechanisms triggered by errors and conflicts dissociate.