Manipulation with no or partial vision

The present research investigated the role of vision in closed- and open-lo op processing during manipulation. In Experiment I, participants performed common manipulatory tasks with 100% accuracy in less than 1 s without visio n. In Experiment 2, the effects of extensive practice of a peg-in-hole task were examined within 4 functionally significant stages of manipulation. Pe rformance was consistently Easter with than without vision in the prereach, grasp, and transport + insert stages; reverse effects were observed during the reach stage. In Experiment 3, the effects of practice with partial vis ion were examined: Participants initially learned the peg-in-hole task with full vision and then transferred to learning the same task with vision ava ilable only during 1 functional stage. Overall, performance was fastest whe n vision was limited to the prereach and reach stages.