Handedness and motor programming in manual movement control.

Abstract

Four studies with a unidimensional, cursor-positioning task, employing both response-priming and response-precuing techniques, were performed to evaluate differences in motor control between the preferred and nonpreferred hands. None of the major hypotheses proposed previously to explain these differences (e.g., ones based on practice, force variability, feedback-processing speed, hemispheric specialization, and sequential movement control) was supported. Instead, hand differences may stem from greater automaticity during the execution of motor programs for moving by the preferred hand. Furthermore, the present studies do not support the distinctive-features model of motor programming proposed by Rosenbaum and other investigators. Such programs appear to be hierarchically organized and serially executed, with information about movement direction required before movement-extent information is used. This conclusion is consistent with results obtained during both the initial programming of aimed movements and their reprogramming when the original information for them turns out to be incorrect.