Human Factors and Behavioral Science: Central Control of Movement Timing

A fundamental concern of behavioral science is to understand how we control the movements of our bodies. This paper examines the timing of body movements: As we walk, talk, or type, how are the delays between the phases of these various activities controlled? A popular means of approaching this question has been to consider two extreme views of how movements might be timed. One view holds that delays between the phases of a movement sequence are controlled by using feedback from each phase to trigger the next. Since the feedback can arise from receptors in the peripheral nervous system-- within the muscles, joints, and skin--this view is often referred to as the "peripheralist" theory. 1 The other view holds that movement timing is controlled by plans or "programs" that allow sequences to be performed without the aid of feedback. This view is often called the "centralist" theory. * Work done at Bell Laboratories. Now at School of Language and Communication, Hampshire College, Amherst, Massachusetts. ®Copyright 1983, American Telephone & Telegraph Company. Copying in printed form for private use is permitted without payment of royalty provided that each reproduction is done without alteration and that the Journal reference and copyright notice are included on the first page. The title and abstract, but no other portions, of this paper may be copied or distributed royalty free by computer-based and other informationservice systems without further permission. Permission to reproduce or republish any other portion of this paper must be obtained from the Editor.