Implicit motor learning from target error during explicit reach control.

Many studies have shown adapted reaching in the face of altered visual feedback. These studies typically involve iterative corrections to the error induced by the perturbation until relatively normal performance is achieved. Here, we investigate whether adaptation (indexed by aftereffects) can occur when direct corrections to a target are inhibited by giving participants an explicit reach task. During the exposure phase of our study, participants were instructed to undershoot a target that imperceptibly moved between movement onset and movement end. The size of the target displacement was gradually increased, while the instructed undershoot distance was equivalently increased, such that participants were, unknowingly, aiming to the same location throughout exposure. When participants were subsequently instructed to aim at the target during the post-test, they overshot the target, suggesting that adaptation had occurred in the presence of an explicit task and in the absence of direct corrections to the target perturbation.