Mutual interpersonal postural constraints are involved in cooperative conversation.

The research was designed to evaluate interpersonal coordination during conversation with a new measurement tool. The experiment uses an analysis based on recurrence strategies, known as cross recurrence quantification, to evaluate the shared activity between 2 postural time series in reconstructed phase space. Pairs of participants were found to share more locations in phase space (greater recurrence) in conditions where they were conversing with one another to solve a puzzle task than in conditions in which they conversed with others. The trajectories of pairs of participants also showed less divergence when they conversed with each other than when they conversed with others as well. This is offered as objective evidence of interpersonal coordination of postural sway in the context of a cooperative verbal task.