VARIABILITY OF PRACTICE AND CONTEXTUAL INTERFERENCE IN MOTOR SKILL LEARNING

The purpose of this study was to investigate whether learning benefits in multiple-task learning situations are a result of contextual inter ference or of schema enhancement related to the amount of variability in the practice session. Two experiments were designed that replicated and extended the experiment reported by Wulf and Schmidt (1988). In a 2 (same vs. different relative time) x 2 (blocked vs. random practice schedule) design, 48 right-handed subjects were randomly assigned to one of four experimental conditions. A tapping task was employed that required a right-handed tap of three small brass plates arranged in a diamond pattern. Each segment had a specific time requirement. Target times and response times were provided on a computer screen directly i n front of the subject. Each subject participated in two acquisition s essions (i.e., 198 practice trials) and was tested for learning on sev eral different retention and transfer tests. In Experiment 2, a contro l group was added that received no acquisition phase. Results of both experiments showed a typical centextual interference effect, with depr essed scores by the random groups during acquisition but significantly better scores than the blocked groups on several retention and transf er tests. Certain characteristics of the tests were found to influence the demonstration of the practice schedule effects. These results wer e consistent with predictions from Magill and Hall (1990) that the lea rning benefits of contextual interference are more likely to occur whe n skill variations are from different classes of movement and that the amount of variability in practice is more influential when the to-be- learned tasks are parameter modifications of the same generalized moto r program.