Angular Displacement of Visual Feedback in Motion and Learning

Abstract

The main hypothesis was that angular displacement of the visual feedback of motion produces no disturbance of behavior within a limited “normal” range, but that a breakdown angle can be found beyond this range which will produce disturbance in motion control in proportion to the magnitude of the feedback displacement. Experimental results concerning maze tracing and circle drawing specifically supported the hypothesis. In circle drawing, both compensatory visual displacement errors and direct motor error in control of the pattern of motion conformed to the theoretical assumptions. In addition, data on learning in the two tasks conformed to theoretical assumptions that specific sensory-feedback factors determine differences in motor learning and that the spatial properties of such feedback determine the level of performance during learning. The guiding hypothesis was derived from a neurogeometric conception of brain function, which assumes that each internuncial cell acts as a space detector to record the angular difference between a given neural state of a movement and its sensory feedback. The data contribute positively to our understanding of the brain mechanism of motion and of the sensory process as a neurogeometric detector system. The experiments also define the significance of the methods of sensory-feedback analysis in disclosing the nature of intrinsic geometric relationships between the sensory and motor systems that determine learning and the organization of motion.