Multimodal assessment of biobehavioral synchrony in parent–child dyads: A multimethod approach

Dyadic synchrony—the temporal coordination of behavioral and physiological processes between interacting partners—plays a vital role in social development and may reveal biobehavioral mechanisms underlying social difficulties. However, current measures of biobehavioral synchrony vary considerably across studies, limiting our understanding of how different patterns relate to social functioning. This dissertation offers a multimodal assessment of cardiac and behavioral synchrony in parent–child dyads, including those with and without autism, during free play. It combines manual and automated methods to analyze audio, video, and ambulatory electrocardiograph data. It applies advanced time-series analyses to explore the relationships among trend, concurrent, and lagged synchrony measures across cardiac and social-communication processes. Findings suggest that cardiac synchrony and vocal turn-taking patterns may serve as markers of relational engagement that explain variability in children's social communication abilities; however, different synchrony metrics capture distinct temporal dynamics, underscoring that cardiac and behavioral synchrony are multidimensional and that metrics should not be treated as interchangeable.