Self-Organized Complementary Coordination: Dynamics of an Interpersonal Collision-Avoidance Task

^(*) Center for Cognition, Action, & Perception and University of Cincinnati, USA
^(†) Department of Psychology, College of the Holy Cross, USA
E-mail: richamo@ucmail.uc.edu, harri2sv@ucmail.uc.edu, mayrn@mail.uc.edu, kallenrl@ucmail.uc.edu, rschmidt@holycross.edu

Abstract

The current study investigated the movement dynamics of a complementary collision-avoidance task. Participant pairs performed a repetitive targeting task in which they moved computer stimuli back and forth between sets of target locations without colliding into each other. Pairs converged onto a stable relative phase relationship of around 35°, with one participant spontaneously adopting the role of "phase leader" and the other participant adopting the role of "phase follower". In addition, those participants who adopted the role of phase leader tended to exhibit more of a straight-line trajectory between targets, whereas participants who adopted the role of phase follower tended to exhibit a more elliptical trajectory. This role differentiation was essential to task success and reflected the spontaneous relaxation and recruitment of available movement degrees-of-freedom defined across the joint-action system.