Motor simulation is disturbed when experiencing pain.

While the contribution of social processes to pain perception is well documented, surprisingly little is known about the influence of pain on social perception. In particular, an important question is how pain modulates the processing of other people's actions. To address this question, the current study tests, using automatic imitation, the hypothesis that pain interferes with motor simulation-that is, the processing of observed actions in the motor system. Participants in both experiments performed an automatic imitation task requiring them to abduct their index or little finger while they saw someone else performing either a congruent or incongruent action. Automatic imitation was measured in a pain-free context, a context where pain was coupled to the execution of a movement (experiment 1), and a context where pain occurred randomly (experiment 2). The results revealed that automatic imitation, indexed by slower responses on incongruent compared with congruent trials, was reduced when experiencing pain, both when pain was linked to movement execution and when it was not. Thus, the current study shows that pain leads to reduced motor processing of others' behavior and, as such, has important implications for understanding the social difficulties associated with pain.