Cognitive underpinnings of social interaction.

Human social interaction is part of what defines us. Here I present an overview of recent studies of imitation, a subdomain of social interaction that can be dissected and examined in a scientific fashion. I use these studies to test two core claims: (a) that there is more than one copying mechanism in the human brain and (b) that mimicry (a form of copying) is particularly relevant for understanding social behaviour. Evidence in favour of the first claim comes from neuroimaging studies that show distinct brain systems for understanding action kinematics, action goals, and irrational actions. Further studies of participants with autism show abnormal copying of irrational actions. Evidence in favour of the second claim comes from behavioural studies of the social cues that prime mimicry and from neuroimaging studies of the pathways involved in this priming. These studies suggest that medial prefrontal cortex has a core role in controlling mimicry responses and support the STORM (social top-down response modulation) model. Future work should determine what organizing principles govern the control of social responses and how these critical mechanisms for interpersonal connection differ in autism.