On Response-Response Compatibility 1

Abstract

This study was designed as a first step in the investigation of response-response compatibility effects, a compatibility phenomenon hypothesized by Fitts and his associates.

A two-hand cranking task was used in which S could, by manipulating two cranks, adjust a mechanical stylus to any one of one hundred points on a ten-by-ten matrix. The four possible combinations of clockwise and counterclockwise movements of the two cranks made up four response conditions. Three different stimulus types (codes) were used: digital, pictorial, and instructional. The stimuli, projected onto the rear side of a translucent screen located directly in front of S, indicated the point on the matrix to which S was to move the stylus. The target series used for each of the three stimulus types required the use of the four response conditions with equal frequency.

It was found that speed of both total adjustment and initial response was dependent upon the particular stimulus type used, but not dependent upon response conditions. In contrast, number of correct initial movements was dependent upon response conditions but not stimulus types. The latter was, however, a function of response sets rather than compatibility. No evidence of significant interaction was found.

The present findings fail to support the hypotheses of Fitts and his associates and time and motion principles which also, in effect, contend that R-R compatibility effects exist. Furthermore, the existence of response sets with no corresponding effect on the over-all efficiency of the system suggests that sets and compatibility are two different and not necessarily interacting phenomena.