Visual-spatial and anatomical constraints interact in a bimanual coordination task with transformed visual feedback

There is a debate in the literature about the influence of spatial and anatomical constraints on bimanual coordination dynamics. In the present experiment, participants swung hand-held pendulums about the wrist while attending to visual feedback about relative phase (superimposed phase plots of each pendulum) that was displayed on a screen. Participants were instructed to maintain in-phase or anti-phase coordination in the visual display. Visual-spatial and anatomical constraints were dissociated by introducing a phase shift in the visual display so that visual feedback differed from the movements being performed by the participants in 15 degrees increments from -180 degrees to +180 degrees. Analysis of mean relative phase and its variability suggested that visual-spatial and anatomical constraints interact in bimanual coordination dynamics.