Based upon a conference held in Bethesda in 1985, this volume brings together the research and theoretical perspectives of experts in the developmental aspects of motor control, coordination, and skill in the mentally handicapped. This is accomplished within the context of cognition. Section I deals with the dynamics of controlling movement skill and the nature of the variables that mediate the learning of motor skills. Sections II and III examine the traditional area of research in motor behavior, i.e., the speed of information processing and reaction time paradigms. The last section discusses the issue of training to minimize the effects of mental retardation on motor behavior.