motor development are no doubt numerous, but three are especially significant: 1. One concerns a shift from studying either sensory or motor processing to investigation of the relations between the two. 2. The second is connected to the new emphasis on action, and its implications for goal-directed and intentional behaviour extending over time. 3. Lastly, new theories and methodologies provide access to new tools for studying and conceptualizing the developmental process. 1.-One of the most enduring legacies of the behaviorist perspective has been a focus on the stimulus and the response to the exclusion of the relation between them (Pick, 1989). Historically, this bias translated into a research agenda in which the investigator was concerned with either perceptual or motor competence, but rarely the relation between them.