Mimicry and social affiliation with virtual partner are decreased in autism.

Copying other people's mannerisms (i.e., mimicry) occurs spontaneously during social interactions, and is thought to contribute to sharing emotions, affiliation with partners and interaction quality. While previous research shows decreased mimicry of emotional facial expressions in autism spectrum disorders (ASD), we know relatively little about how non-emotional, non- facial behavioural mimicry manifests and, more importantly, what it means for autistic individuals' social interactions. In a controlled, semi-naturalistic interaction setting, this study examined how often autistic and neurotypical (NT) children mimicked a virtual partner's non-facial mannerisms as they engaged in an interactive story-telling activity. Subsequently, children reported how affiliated they felt towards their interaction partner using an established implicit measure of closeness and a set of questions. Results revealed reduced mimicry (p =.001, φ =0.38) and less affiliation (p =.01, φ =0.33) in ASD relative to NT children. Mimicry was associated with affiliation for NT (r(23) =0.64, p =.0009), but not ASD, children (r(31) =0.07, p =.72). These results suggest an autism-associated reduction in mimicry and that mimicry during social interactions may not substantially contribute to affiliation in autism.