Effects of s-R compatibility and task difficulty on unimaimual movement time.

Using a system in which S controlled a cursor on an oscilloscope screen by moving a lever, the S-R relationship on either hand could be reversed. This system was used in two experiments designed to investigate the effect on unimanual movement time of varying S-R compatibility, and task difficulty as defined by Fitts (1954). The results indicated the necessity of specifying task difficulty in an investigation of S-R compatibility. Further, it was found that as task difficulty increased the difference in performance between the right and left hands became more marked.