SPECTRAL ANALYSIS AND THE STUDY OF INDIVIDUAL DIFFERENCES IN THE PERFORMANCE OF ROUTINE, REPETITIVE TASKS

Abstract

ABSTRACTFor the purpose of studying individual differences in the performance of routine, repetitive tasks, mathematical methods of analysis of data which is ordered along the time dimension are considered. Spectral analysis is chosen as the best method, since it gives a complete summarization of the stationary properties of time‐ordered data, and the measures derived from it possess convenient and orderly statistical properties. Spectral analysis decomposes the total oscillation of a time‐series into oscillations of varying rates, specifying the relative contribution of each of the components of oscillation.Spectral analysis as an analytical tool is applied to available psychological data; in one case, to a study of “mental blocking,” and in another, to a study of serial patterns of response in an auditory discrimination. In both cases, spectral analysis leads to a modification and clarification that had been reached by the previous authors. Spectral analysis is then applied to the experimental data of the present paper.The experimental task was that of jabbing a stylus repeatedly at a target line or lines. The deviations of the jabs from a reference line were measured in serial order, and the series were then subjected to a spectral analysis. Thirty‐three subjects were tested on five variations of the main task. Fifteen of the subjects were retested a month later. Task variations proved unimportant, but reliable individual differences were found in three measures, two of which did not depend on spectral analysis and one of which did.These three measures were related to general personality characteristics by means of an inductive process. An individual who had had considerable contact with the experimental subjects in interview situations over a period of two years was asked to suggest personality factors which might have produced the differences found on each of the three measures. Without knowledge of the nature of the experimental measures, he suggested personality factors corresponding to them. These personality factors and their relation to routine, repetitive tasks are discussed.