THE LEARNING OF GENERALIZED MOTOR PROGRAMS AND MOTOR SCHEMATA - EFFECTS OF KR RELATIVE FREQUENCY AND CONTEXTUAL INTERFERENCE

Earlier, we found that the learning of generalized motor programs (GMPs) can be enhanced by a reduced relative frequency of knowledge of results (KR), as compared to 100% KR, or by random practice, as compared to blocked practice; at the same time, the learning of movement parameters. i.e., schema learning, tended to be degraded by these factors (Wulf, Schmidt and Deubel, 1992; Wulf and Lee, 1992). The purpose of the present study was to replicate these results, and to determine whether a combination of both factors would yield additive effects. Therefore, the effects of a reduced relative frequency of KR and random practice were examined interactively. Subjects practice three movement patterns with the same relative timing and the same relative amplitudes, but with varied absolute amplitudes. In a 2 (KR) x 2 (Contextual Interference) design, KR was either presented on 67% or on 100% of the practice trials, and the different task versions were practiced either in a random or in a blocked order. Similar to the previous studies, both a reduced relative frequency of KR and random practice enhanced GMP learning; however, there were no effects on parameter learning. Also, there was no evidence for additive effects of a reduced relative KR frequency and random practice.