Bimanual joint action: Correlated timing of "bimanual" movements accomplished by two people


Many actions at work or play require carefully coordinated movements from a pair of performers. At the individual level, temporal coordination of the limbs has been observed in bimanual pointing movements even when made to targets of different amplitudes. Timing of the arms is not independent; rather there is a natural temporal coupling. The aim of this experiment was to investigate whether the temporal characteristics of pointing movements can be observed under joint conditions. Sixteen pairs of participants made short and long, unimanual and bimanual pointing movements. In the unimanual and bimanual solo conditions, participants made the movements alone. In the joint condition, each participant contributed one arm to the joint "bimanual" movements. Temporal coupling and correlation between the arms were examined. Pointing movements were strongly coupled in the bimanual solo condition, but they were not coupled in the unimanual solo and bimanual joint conditions. The initiation and termination of the arms were not correlated in the unimanual solo condition (initiation r = .01, termination r = .03). Small-to-medium correlations (r = .19, r = .24) were observed in the bimanual joint condition and found to be significantly larger than the unimanual solo condition (p <.01, p =.01). As expected, there were large correlations in the bimanual solo condition (r = .91, r = .81). Our findings suggest that temporal coupling across the arms does not occur between individuals but there is evidence for some synchronisation in the bimanual joint condition.

Acknowledgments: This research was funded NSERC