On Response-Response Corn pati bility,

This stu & was designed as a first step in the investigation of response-response compatibility effects, a compatibility phenomenon hypothesixed by Fitts and his associates. A two-hand cranking task was used in which S could, by manipulating two cranks, adjust a mechanical stylm 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 locateddirectly in front of S, indicated the point on the matrix to which S was t o move the sglus. The target series used for each of the three stimulus types required the use of the four response conditions with equal frequency. I t was found that speed of both total adjustment and initialresponse 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 fa i l 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 ejTciency of the system suggests that sets and compatibility are two dzfferent and not necessarily interacting phenomena. A facilitative interaction between the display and the control in a man-machine system has been demonstrated in several investigation