Stabilizing perceptual-motor asymmetries during social coordination

• We examine spatial asymmetries during social coordination.
• Coordination stability is maintained by spontaneous movements.
• Degree of spontaneous movements reflects inherent movement stability.
• Recruiting or suppressing motor degrees-of-freedom stabilizes social coordination.

The current paper presents two studies that examine how we compensate for asymmetries during interpersonal coordination. It was predicted that destabilizing effects of asymmetries are offset through the recruitment and suppression of motor degrees-of-freedom (df). In Experiment 1, this effect was examined by having participants coordinate line movements of different orientations. Greater asymmetries between participants yielded greater spatial deviation from the intended orientation, suggesting a recruitment of df. In Experiment 2, participants coordinated circle and line movements. Results showed that line became more circular and circles became more linear, specifically along the axis of the line movements. These results suggested that df were both systematically suppressed (in the case of circle movements) and recruited (in the case of line movements) to stabilize an asymmetric coordination task.