Rocking together: dynamics of intentional and unintentional interpersonal coordination.

Everyday human actions often occur in a social context. Past psychological research has found that the motor behavior of socially situated individuals tends to be coordinated. Our research performed over the last 20 years has sought to understand how the mutuality, accommodation, and synchrony found in everyday interactional coordination can be understood using a dynamical theory of behavioral order, namely coordination dynamics. Using laboratory interpersonal tasks, we have demonstrated that when two people are asked to rhythmically coordinate their limbs they show behavioral phenomena identical to those found in bimanual interlimb coordination, which has been mathematically modeled as a dynamical process. Research has demonstrated that these same dynamical organizing principles can coordinate the rhythmic movements of two people unintentionally and that the weaker, intermittent coordination that ensues is affected by both perceptual (e.g., attentional focus and information pickup activity of the visual system) and dynamical constraints (e.g., intrapersonal rhythmic synergies and period basin of entrainment). Other research has investigated how traditional social and personality properties of a dyad (rapport, social competence) relate to dynamical properties of a dyad’s coordinated movements and how the stability of coordinated movements mirrors the stability of mental connectedness experienced in social interactions.

Dynamics of Interpersonal Coordination

In investigations into perception-action systems, variability of observable behavior may be considered to (a) interfere with inquiry, (b) be neither detrimental nor particularly useful to inquiry, or (c) play a crucial role in inquiry. The authors underscore recent suggestions that alternative (c) is a preferred strategy for the study of many motor behaviors. In tutorial fashion, the authors review the concepts of variability and determinism with respect to postural and rhythmic movements. Study of the variability of those behaviors has revealed crucial features suggestive of underlying mechanisms and control, such as particular blends of noise and determinism (piecewise determinism). It has also revealed general lessons (for example, more variable does not mean more random and more controllable does not mean more deterministic) that may extend to other classes of perceptual-motor behavior.

Variability and Determinism in Motor Behavior

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 deg. and 180 deg. These results support the hypothesis that dynamical organizing principles are involved in natural interpersonal synchrony.

Evaluating the Dynamics of Unintended Interpersonal Coordination

There is a need for a collective variable that captures the dynamics of team sports like soccer at match level. The centroid positions and surface areas of two soccer teams potentially describe the coordinated flow of attacking and defending in small-sided soccer games at team level. The aim of the present study was to identify an overall game pattern by establishing whether the proposed variables were linearly related between teams over the course of the game. In addition, we tried to identify patterns in the build-up of goals. A positive linear relation and a negative linear relation were hypothesized for the centroid positions and surface areas respectively. Finally, we hypothesized that deviations from these patterns are present in the build-up of goals. Ten young male elite soccer players (mean age 17.3, s=0.7) played three small-sided soccer games (4-a-side) of 8 minutes as part of their regular training routine. An innovative player tracking system, local position measurement (LPM), was us...

Oscillations of centroid position and surface area of soccer teams in small-sided games

In 1:1 frequency locking, the interlimb phase difference phi is an order parameter quantifying the spatial-temporal organization of 2 rhythmic subsystems. Dynamical modeling and experimental analyses indicate that an intentional parameter phi psi (intended coordination mode, phi = 0 degrees or phi = 180 degrees) and 2 control parameters omega c (coupled frequency) and delta omega (difference between uncoupled eigen-frequencies) affect phi. An experiment was conducted on 1:1 frequency locking in which phi psi, omega c, and delta omega were manipulated using a paradigm in which a person swings hand-held pendulums. As delta omega deviated from 0, the observed phi deviated from the phi psi, indicating a displacement in the phi attractor point. The displacements were exaggerated by increasing omega c. The displacements were coordinated with a decrease in the stability of phi and with higher harmonics in power spectrum of phi. Implications of the results for modeling interlimb coordination are discussed.

Barbara K. Shaw

Papers

Coupling dynamics in interlimb coordination.