Social coordination dynamics: Measuring human bonding

Abstract

Spontaneous social coordination has been extensively described in natural settings but so far no controlled methodological approaches have been employed that systematically advance investigations into the possible self-organized nature of bond formation and dissolution between humans. We hypothesized that, under certain contexts, spontaneous synchrony—a well-described phenomenon in biological and physical settings—could emerge spontaneously between humans as a result of information exchange. Here, a new way to quantify interpersonal interactions in real time is proposed. In a simple experimental paradigm, pairs of participants facing each other were required to actively produce actions, while provided (or not) with the vision of similar actions being performed by someone else. New indices of interpersonal coordination, inspired by the theoretical framework of coordination dynamics (based on relative phase and frequency overlap between movements of individuals forming a pair) were developed and used. Results revealed that spontaneous phase synchrony (i.e., unintentional in-phase coordinated behavior) between two people emerges as soon as they exchange visual information, even if they are not explicitly instructed to coordinate with each other. Using the same tools, we also quantified the degree to which the behavior of each individual remained influenced by the social encounter even after information exchange had been removed, apparently a kind of social memory.

Acknowledgements

Work supported by the National Institute of Mental Health (NIMH Grants MH42900 and MH01386 to JASK). The preparation of this manuscript was supported by the Programme Initiative from the Fondation de l'Académie des Sciences (to OO), the Enactive Interfaces European Network (IST contract #002114 to JL) and the National Institute of Neurological Disorders and Stroke Grant (NS48229–01A1 to JASK).

The authors would like to thank Craig Richter (Florida Atlantic University), Thomas Stoffregen (University of Minnesota), and Erwann Michel-Kerjan (The Wharton School of the University of Pennsylvania) for helpful discussions on early versions of this manuscript.

Notes

¹A beautiful example of the same audience clapping in synchrony at two separate moments of a live musical show is seen in the world-famous New Year's Concert given every year by the Vienna Philharmonic Orchestra in Austria while and after the Radetzky March by Johann Strauss Jr. is played. This is an unusual piece of classical music in which the conductor leads not only the orchestra but also the audience. Upon a visual cue from the maestro, the audience claps in synchrony with the music. This collective clapping is intentionally synchronized both with auditory and visual signals coming from stage. Although, at the end of the performance, pacing stimuli are no longer provided by the orchestra and conductor, the audience still applauds in unison. From an external point of view both modes of synchronized clapping might look similar, however they are governed by two different mechanisms: intentional and spontaneous synchronization, respectively.

²This experimental feature is crucial since the presence of a metronome creates the possibility that the pair will synchronize primarily with the metronome and not necessarily spontaneously with each other (see Schmidt et al., 1990).

³Although interesting, the latter result should be considered with caution since it reports a comparison between two eyes-closed segments from two different conditions.