Knowledge of results and motor learning: a review and critical reappraisal.

Previous analyses of knowledge of results (KR) and motor learning have generally confounded the transient performance effects as shown when KR is present and the relatively permanent (i.e., learned) effects that we argue should be evaluated on a transfer test without KR. In this review, we classify investigations according to this distinction, and a number of new relations emerge between KR and both learning and performance. In addition to the motivational and associational roles of KR, we emphasize that it also acts as guidance, enhancing performance when it is present but degrading learning if it is given too frequently.