Effects of duration and activity during the post-KR interval on motor learning

Summary The present experiment assessed a traditional assumption regarding the informational role of knowledge of results (KR) in motor learning. The assumption is that learning is facilitated to the degree that KR is used to reduce goal-directed error. To test the assumption we examined two specific predictions that have been made with respect to post-KR interval effects: that the interval should be long enough for action-planning operations to occur and that the interval be free from interpolated activities that might prevent action-planning operations. The present study used a factorial arrangement of post-KR interval durations and interpolated activities during the post-KR interval to test these predictions. Using a movement timing task, we found that, contrary to predictions, learning was not facilitated by lengthening the post-KR interval. Also, in opposition to existing theory, the data revealed that interpolated activities, when combined with longer post-KR durations, were not detrimental to learning and actually improved learning in some instances. These findings are discussed together with recent evidence regarding various KR effects that suggest that many theoretical assumptions about the role of KR need revision.