Proceedings of the Annual Meeting of the Cognitive Science Society

We study the performance of human subjects in a task which requires multi-jointed reaches to be made to targets spaced over a wide area. In accordance with established research, we find that subjects' reaches are not accurate when they carmot see either their hands or the targets. The errors subjects make are different at different targets, suggesting that they are due to an error in the plaiming of movements. However, contrary to existing models of this error, we find that it is highly idiosyncratic. This leads to the rejection of the most straightforward model of how reaching is learned, and poses problems which a future model must address.