Amplitude differences, spatial assimilation, and integrated feedback in bimanual coordination.

The purpose of the experiment was to determine the influence of Lissajous feedback on 1:1 bimanual coordination patterns (0 degrees , 90 degrees , and 180 degrees phase lags) when the movement amplitudes of the two limbs were different (30 degrees , 60 degrees ). The present data supports the notion that the lead-lag relationship as well as amplitude assimilation observed in the literature can be partially attributed to the visual-perceptual factors present in the testing environment. When participants are provided integrated feedback in the form of Lissajous plots much of the lead-lag and amplitude assimilation effects were eliminated, and relative phase error and variability were also greatly reduced after only 3 min of practice under each condition.