The control of two-element, reciprocal aiming movements: Evidence for chunking

This study evaluates the chunking hypothesis in the context of two-element, reciprocal aiming movements. The chunking hypothesis assumes that movements toward small targets require a movement stop while movements toward large targets require a movement reversal. According to the chunking hypothesis, a movement reversal allows for a functional coupling or linkage between the forward and backward movement such that braking energy generated by antagonist activity in the forward movement is stored as elastic energy and re-utilized as acceleration energy in the backward movement (Guiard, 1993). An experiment is reported which examined movement kinematics of left-right reversal movements using four different target combinations; small-small, small-large, large-large, and large-small, for left and right targets, respectively. The results accommodated predictions derived from the chunking hypothesis. Several implications for motor control theory are discussed.