Interpersonal coordination in three-year-old children: Functions, morphology, and temporality.

The temporal dimension of interpersonal macro- and micro-coordinations between young children and social partners, as well as its functions, has been well documented. However, the different morphologies that bodily micro-coordination can adopt during these interactions have received considerably less attention. This research studied the temporality and morphology of spontaneous child-adult micro-coordinations and their associated functions. For this purpose, three-year-old children (N = 35) were randomly assigned to storytelling sessions based on emotional or referential stories. Using motion capture technology, we traced rapid and spontaneous coordinations between torso movements, ranging from 0 to 1000 milliseconds. Results show that both mirror-like and anatomical coordinations spontaneously emerge in interactions between 3-year-old children and unfamiliar adults. Importantly, slightly delayed in time, mirror-like coordinations predominantly occur in emotional interactions, while zero-lag, anatomical coordinations occur in referential interactions. These results suggest that these morphologies might indeed inform different functions of coordination, as previously theorized in the literature. The evidence found could contribute to a better understanding of how interpersonal coordination shapes social interaction very early in development.