Interpersonal synchrony and affiliation in typically developing children and children with emerging emotional and behavioural difficulties

Interpersonal synchrony (IS) is the temporal co-ordination of behaviour during social interactions. For typically developing (TD) children, IS has important social consequences, promoting affiliation and prosocial behaviour between social partners, and informing children’s understanding of the relationships of others. However, little is known about the factors that contribute to the affiliative effects of IS; whether IS holds social significance for atypically developing children; and what factors account for variation in social sensitivity to IS. This thesis explored how IS influenced the social judgements of typically and atypically developing children. In Chapter 2, findings from a novel experimental paradigm indicated that both simultaneity and temporal regularity contributed to the affiliative effects of IS when TD children witnessed IS, with this effect mediated by their perceptions of partners’ ‘togetherness’. However, when children experienced IS in a limited social context, no affiliative effects were observed, suggesting that positive social effects arise from experienced IS only when social presence/partner engagement is sufficiently salient. The same tasks were then used to investigate the social effects of IS in children with emerging emotional and behavioural difficulties (EE&BDs) (Chapter 3), finding limited evidence that IS was socially relevant for this group. Chapter 4 profiled two fundamental synchrony-related processes in children with EE&BDs: synchrony perception and motor synchrony. Abilities in both domains varied considerably in the sample, with performance increasing with age. To investigate the processes that might contribute to reduced social sensitivity to IS in children with EE&BDs, Chapter 5 brought together the evidence from Chapter 3 and 4, finding that social sensitivity to IS in children with EE&BDs (Chapter 3) was not related to perceptual and motor synchrony abilities (Chapter 4), or to theory of mind (ToM). Overall, the social judgements of TD children were reliably guided by IS when witnessing IS, but IS had limited social significance for children with EE&BDs. IS likely plays a role in the diverging social experiences of typically and atypically developing children, contributing to differences in social communication commonly observed in atypical development