The visual control of aimed hand movements to stationary and moving targets.

The present study attempted to determine if during short-duration movements visual feedback can be processed in order to make adjustments to changes in the environment. The effect that varying the importance of monitoring target position has on the relative importance of vision of hand and vision of target (Carlton 1981a; Whiting and Cockerill 1974) was also examined. Subjects performed short- (150 ms) and longer-duration (330 ms) aimed hand movements under four visual feedback conditions (lights-on/lights-off by target-on/target-off) to stationary and moving targets. For the lights-off and target-off conditions, the lights and target, respectively, were extinguished 50 ms after movement initiation. For all moving-target conditions, the target started to move as the movement was initiated. Subjects were able to process visual information in 165 ms, as movement endpoints were biased in the direction of target motion for movements of this duration. Removing visual feedback 50 ms after movement initiation did not alter this finding. Subjects performed equally well with target and lights on or off, independent of whether the target remained stationary or moved. Presumably, during the first 50 ms of the movement subjects received sufficient visual information to aid in movement control.