Directional stimulus-response compatibility: a test of three alternative principles

The basis of directional stimulus-response compatibility was studied using a task in which 128 participants moved a cursor into targets with a joystick, resembling the operation of certain industrial and construction equipment. Compatible and incompatible versions of three alternative compatibility principles were compared in all combinations. Visual Field (VF) compatibility was present if cursor and controlling limb movement were in the same direction in the visual field, Control Display (CD) compatibility meant that the control motion was in the same direction as, and parallel to, cursor motion, and Muscle Synergy (MS) compatibility was defined as use of the muscle synergy normally associated with the required direction as seen in the visual field. VF-compatible conditions had significantly shorter reaction, movement and homing times, and fewer reversal errors, for males and females, in two testing sites. These advantages were maintained over practice. VF compatibility was confirmed as a robust spatial compatibility principle that is affected by neither the orientation of the operator's limb or head nor the muscle synergy used in executing the task. It offers not only more rapid performance, but also a markedly reduced rate of potentially dangerous directional errors. The relationship between this finding and theoretical aspects of stimulus-response compatibility is discussed.