The continuous updating of grasp in response to dynamic changes in object size, hand size and distractor proximity

Abstract

Reaching out to pick up an object seems a trivial matter, but selecting the appropriate hand configuration requires a series of complex computations that process the object's dimensions, orientation and environment. A current debate in motor control concerns how and when the motor system responds to unexpected changes in the visual and spatial properties of objects to be grasped. In the current experiment, visual manipulations that increased either target size, distractor proximity or hand size were applied gradually and continuously throughout reach to grasp movements. All manipulations were associated with early and continuous modifications of the grasping component, but only an increase in hand size affected transport characteristics. This suggests that visual information of both the object and the effector are continuously processed in movement computations, in keeping with models of motor control that posit high weighting for online sensory feedback.