How shared goals shape action monitoring.

Cooperation triggers expectations on our partners' contributions to achieve a common goal. A partner, however, may sometimes violate such expectations, driving us to perform immediate adjustments. What neurophysiological mechanisms support these adaptations? We tested the hypothesis of an interaction-specific brain system that can decode a partner's error and promote adaptive responses when cooperating toward a shared goal. During functional magnetic resonance imaging, the participants played short melodies with a virtual partner by performing one note each in turn-taking. A colored cue indicated which melody they had to execute at each trial, thus generating expectations on what notes the partner would play. The participants also performed the task in a perceptually matched Non-Interactive context. The results showed that task interactivity modulates the brain responses to a partner's error in dorsal fronto-temporoparietal and medial cingulo-opercular networks. Multivariate pattern analysis revealed that these neural activations reflect deep decoding of the partner's mistake. Within these networks, the automatic tendency to correct the partner's errors, as indexed by specific reaction times adaptations, depended on the activity of a right-lateralized fronto-opercular system that may enable mutual support during real-life cooperation. Future studies may unveil the role of this putative "interaction monitoring" brain system in social dysfunctions and their motor foundations.