Social bonding is fundamental to human society, and romantic interest involves an important type of bonding. Speed dating research paradigms offer both high external validity and experimental control for studying romantic interest in real-world settings. While previous studies focused on the effect of social and personality factors on romantic interest, the role of nonverbal interaction has been little studied in initial romantic interest, despite being commonly viewed as a crucial factor. The present study investigated whether romantic interest can be (1) predicted by nonverbal dyadic interactive body sway, and (2) enhanced by movement-promoting ('groovy') background music. Participants' body sway trajectories were recorded during speed dating. Directional (predictive) body sway coupling, but not body sway similarity, predicted interest in a long-term relationship above and beyond rated physical attractiveness. In addition, presence of groovy background music promoted interest in meeting a dating partner again. Overall, we demonstrate that romantic interest is reflected by nonverbal body sway in dyads in a real-world dating setting. This novel approach could potentially be applied to investigate nonverbal aspects of social bonding in other dynamic interpersonal interactions such as between infants and parents and in nonverbal populations including those with communication disorders.
Keywords: Granger causality; groove; interpersonal interaction; mixed effect model; romantic interest.
© The Author(s) 2020. Published by Oxford University Press.