Self-regulators - a hidden dimension of interaction: movement similarity and temporal proximity increase the perception of interpersonal coordination in third party observers

In everyday circumstances, humans use a variety of cues to draw rich inferences about the nature of interaction. Among these, we focus on sequences of self-regulatory movements, such as touching behaviours and postural changes, that have long been related to interpersonal coordination understood both in terms of mimicry and synchrony. So far, there has been a severe lack of studies on the third party perception of interactional phenomena, including self-regulators. Here, we investigate which elements of the interactional dynamics induce the perception of interactants' behaviours (represented by self-regulators) as causally related, and show that the most important factor responsible for such attribution is the similarity of observed movements. On a more general plane, we hope to make a step towards uncovering perceptual biases that evolved for interpersonal coordination, thus shedding some light on the human interactional potential and its evolution