Fig. 3.

Change in the adaptation to a pure position- and velocity-dependent force field in experiments 1 and 2. Each point indicates the shape of the force response in a channel trial plotted in coefficient space. The evolution of learning after 0, 2, 6, and 10 trials of the exposure to a force field is shown. As the experiment progressed, the initial response became more position dependent and less velocity dependent. This demonstrates the effect of structural learning, such that once they experience a position-dependent force field for the first time, subsequent adaptation to such a force field was faster and more direct. No significant effect was observed for the velocity-dependent force field.