Learning and Control of Coordinated Motor Patterns: The Programming Perspective
Steven W. Keele University of Oregon
The component-analysis approach to motor skill leaves the impression that improvement of skill is a mere matter of decreasing decision time and selecting more efficient movements. Yet, even the most cursory look at skill suggests there is more than that. People learn to coordinate several movements into a smooth pattern--a field-goal kick, a dive, and so on. There are two implications. One is that, rather than requiring each movement component to be evaluated and another decision made, a whole series of movements often occurs in response to just a single decision. In other words, as practice proceeds it is not just that decision time is reduced, but some decisions drop out altogether as they become redundant when a pattern of movement can be made. As a result attention is freed for more global decisions about the task. The skilled basketball dribbler, for example, can stop worrying about the dribble itself and look for passing opportunities or detect circumstances that require the dribble to be altered. Second, as movements become coordinated, two or more movements may overlap in time as when one learns to coordinate hands, arms, and legs in a tennis serve.
A formal demonstration of the development of a motor pattern with practice was provided in a very simple study by Pew ( 1966). Subjects attempted to keep a constantly moving dot centered on a line. Pressing a left-hand key accelerated the dot leftward; pressing a right-hand key accelerated it rightward. To keep the dot centered they had to alternately press the keys. The results for two men both early and late in practice are shown in Fig. 7.1. The pulses on the keys send the dot back and forth across the center line, and the graph portrays that movement over time. Early in practice behavior is rather erratic. Note the irregularity in pulse height and in interpulse interval. People appear to make a movement, evaluate