The use of vergence information in the programming of prehension

Human prehension requires accurate information on the properties of an obje ct and on the position of the object relative to the body. In principle, pr ehension might be more accurate with binocular rather than monocular vision . Previous studies have shown that the kinematics of prehension are altered when one eye is covered. Unfortunately, the source of the useful binocular information cannot be established using this approach. In the current stud y, we used a perturbation technique to explore whether the human nervous sy stem uses a signal from vergence in prehension. Perturbing vergence caused predictable changes in the kinematics of prehension. Our results thus provi de clear evidence that the nervous system uses vergence information in the programming of prehensile movement.