Visual demonstration and movement production: effects of motoric mediation during observation of a model.

The effect of three observational strategies, namely, passive observation, enactive mediation, and delayed mediation, on the accuracy of imitating a modelled throwing action was assessed with a sample of 12-yr.-old schoolboys in a mixed factorial design. 9 boys were assigned to use one of the strategies to produce the pattern of arm movements displayed on a large video-monitor when the speed of the model's movements was varied at three levels. Accuracy of limb displacement and timing of limb movement relative to the model were the performance measures. The results indicated that limb displacement was most accurate when delayed mediation was used with the slowest display. The production of timing was most accurate when enactive mediation was used with the fastest display. Over-all, the use of the passive observation strategy provided the least accurate performance.