Detecting and responding to biological stimuli such as predators or potential mates is a fundamental and adaptive capability, supported by rain areas such as the posterior superior temporal sulcus (pSTS) which is biased for processing biological motion. The pSTS and the parietofrontal mirror system form part of a wider action observation network (AON), which is thought to underlie many social abilities. Motor resonance (MR) is the activation of matching motor representations during observation of action(s) made by others, and could index mirror activity within the wider AON.
Understanding the neural basis of social behavior has become an important goal for cognitive neuroscience and a key aim is to link neural processes observed in the laboratory to more naturalistic social behaviors in real-world contexts. Although it is accepted that mirror mechanisms contribute to the occurrence of motor resonance (MR) and are common to action execution, observation, and imitation, questions remain about mirror (and MR) involvement in real social behavior and in processing nonhuman actions. To determine whether social interaction primes the MR system, groups of participants engaged or did not engage in a social interaction before observing human or robotic actions. During observation, MR was assessed via motor-evoked potentials elicited with transcranial magnetic stimulation. Compared with participants who did not engage in a prior social interaction, participants who engaged in the social interaction showed a significant increase in MR for human actions. In contrast, social interaction did not increase MR for robot actions. Thus, naturalistic social interaction and laboratory action observation tasks appear to involve common MR mechanisms, and recent experience tunes the system to particular agent types.