The Relationship between a Relatively Complex Motor Skill and Its Components

Abstract

The present study attempts to analyze certain relationships between two-hand and one-hand tracking performance. In two-hand, or total-task, tracking, the Ss may respond simultaneously with left and right hands; in one-hand, or part-task, tracking, the Ss use only one hand. The scores obtained by groups of Ss performing in the part-tasks were used to predict the scores of the total-task of other Ss. The predictions were made by taking advantage of the geometric relationships between the totaland part-tasks. Analyses of this type are important for understanding the structure or composition of certain complex skills. Over the long run, the general aim is to formulate laws by means of which the composition of relatively complex psychomotor activities can be described in terms of part-skills and relations between part-skills. Though relational terms, or terms of interaction, have been assumed by practically all S-R theorists, no notable data bearing on this issue appear to exist in the field of motor skills. One way of proceeding would be to combine an S's part-scores in some fashion, and then to compare this predicted score with the score of his total-task. Such a method would, of course, deal with the prediction of individual differences in total performance by means of observations of individual differences in separately practiced, component performances. The present treatment is different, the study by the use of individual differences still being incomplete. The method used here was to combine the part-scores of separate groups of Ss in order to estimate what other groups would do on the total task. Thus, a test is made of how successful is the prediction of two-hand performance from data on the difficulty of separately performed constituent responses when the part-scores are combined in a simple additive fashion. The adequacy of the combining rule is then evaluated in terms of the part-part interactions suggested by the data.