Learning of a new bimanual coordination pattern was investigated by practicing rhythmical arm movements with a required relative phase of ϕ = 90°. To quantify the learning process, we determined the mean and the standard deviation of the relative phase, and the switching lime from a well-established coordination pattern to the to-be-leamed pattern. We then calculated for each parameter the time constant of improvement. We found that with practice, all three parameter improved but each following a significantly different time-course. We therefore conclude that the learning of a new bimanual coordination pattern is governed by three separate processes, which can be visualized in a potential landscape of the intrinsic dynamics as distinct topographical features—namely, the location, depth, and steepness of the attractor basin.
Nicole Wenderoth and Otmar Bock
Isabelle Sallagoïty, Sylvie Athènes, Pier-Giorgio Zanone and Jean-Michel Albaret
Previous studies have shown the existence of preferred stroke directions and shapes in handwriting. Assuming that such a two-dimensional trajectory formation process relies on the nonlinear coordination between two abstract orthogonal oscillators, a recent study (Athènes et al., in press) investigated the relative stability and the temporal accuracy of such coordination patterns in performing various ellipsoids corresponding to different phase and amplitude relationships between the oscillators. Results showed that only a small subset of the patterns was stable and accurate. The present study tested and verified the assumption that more stable coordination patterns deteriorate less under a speed constraint. In addition, differences between the dominant and nondominant hands gave insights into various effects modulating the stability and accuracy of such preferred patterns. Evidence of preferred coordination patterns and the predictability of their deterioration corroborate the existence of dynamics underlying handwriting in terms of nonlinearly coupled oscillators.