Musical behaviours, such as singing, dancing and musical production, encourage high levels of interpersonal synchrony. In adults, interpersonal synchrony (i.e. moving in time with others) has been shown to encourage affiliative behaviours among those involved. People are more cooperative, helpful, and trusting toward people with whom they have moved synchronously compared to asynchronously. Until the present thesis, it was unknown if these affiliative effects of interpersonal synchrony influenced social behaviour from an early age. In Chapter 2, I provided the first evidence that 14-month-old infants are more helpful toward synchronously- compared to asynchronously-moving partners. In Chapter 3, I showed that interpersonal synchrony only boosts infant helping directed toward their synchronously-moving partner, but not a neutral stranger. However, in Chapter 4, I showed that infants are more likely to help the positive affiliate (“friend”) of their synchronously-moving partner over the “friend” of their asynchronously-moving partner. Chapter 5 explores how background music in Chapters 2-4 contributed to the overall experience. Here, I found that even in a non-musical context, infants still helped synchronously-moving partners more than asynchronously-moving partners. However, infants were more distressed and took more time to help than in Chapters 2-4, suggesting that music may provide an emotionally regulating context within which interpersonal synchrony can be experienced. Together, these findings suggest that behaviours encouraging high levels of synchronous movement, such as musical behaviours, have important consequences for early social development.

Doctor of Philosophy (PhD)

Dissertation