Evaluating the dynamics of unintended interpersonal coordination

Past research has shown that interpersonal interactions are characterized by a tacit coordination of motor movements of the participants and has suggested that the emergent. synchrony might be explained by a coupled oscillator dynamic. This study investigates whether unintended between-person coordination can be demonstrated in a laboratory task that will allow an evaluation of whether such dynamical processes are involved. Ten pairs of participants performed a simple rhythmic task in which they had visual information about each other's movements but had no goal to coordinate. A cross-spectral analysis of the movements revealed higher coherence and a distribution of relative phase angles that was dominated by values near 0 degrees and 180 degrees. These results support the hypothesis that dynamical organizing principles are involved in natural interpersonal synchrony.