Movement Synchrony in the Mirror Game

Abstract

The significance of the body-mind link and the contribution of nonverbal communication in the context of psychotherapy is enjoying increased interest. Yet, the main measurements used in psychotherapy studies rely mostly on verbal measures, missing other channels of communication that would allow rich and implicit, nonverbal information. The present study is a first step toward using the mirror game (MG) as a standardized mimicry task that involves the assessment of movement synchrony as a nonverbal outcome measure for psychotherapy research. The aims of the study were twofold: (a) to investigate the possibility of automated analysis of synchrony in the MG, detecting the different roles of leadership in the game, and (b) to validate the synchrony quantified by computer algorithms with a human-rated prosocial scale. All participants (N = 33) played the MG with a gender-matched expert player. Body motions of interacting pairs were assessed using motion energy analysis. Frequency of movement synchrony was computed by windowed cross-lagged correlation and a peak-picking algorithm. Independent observers rated items with respect to prosocial parameters, using the MG scales. The algorithm allowed to differentiate quite accurately between the various roles of leadership. Significant correlations were found between the MG human-rated scales and computer-detected synchrony. High frequency of synchronized movements was linked with high levels of having fun, shared affect, and reference to the other, and with low negative affect. The MG provides a standardized and flexible paradigm for the investigation of movement synchrony. The use of both automated detection and human rating reveals the potential application of the MR in research and clinical use.