Abstract
This study aimed to investigate the effects for timing of the presentation of knowledge of results (KR) on performance during training. Three experiments were conducted, and in all of them, the motor task was to achieve a grasping force of 40% of the maximum grasping power. In Experiment 1, the duration between the end of the motor task and the presentation of KR (KR delay) was held constant with no interval, and the duration between the presentation of KR and the next trial (post-KR delay) was varied. In Experiment 2, the intertrial interval was held constant at an interval of 8 sec, and the set of the durations for KR delay and post-KR delay were varied. In Experiment 3, KR delay was held constant at an interval of 7 sec, and the post-KR delay was varied. The results of the above experiments revealed the following two main findings:
(1) Performance degraded when post-KR delay was shortened;
(2) Lengthening KR delay up to 7 sec did not by itself affect performance, however, performance degraded more than (1) when KR delay was lengthened and post-KR delay was shortend at the same time.
