The utilization of visual information in the control of rapid sequential aiming movements.

Two experiments were conducted to examine the role of vision in the execution of a movement sequence. Experiment 1 investigated whether individual components of a sequential movement are controlled together or separately. Participants executed a rapid aiming movement to two targets in sequence. A full vision condition was compared to a condition in which vision was eliminated while in contact with the first target. The size of the first target was constant, while the second target size was varied. Target size had an influence on movement time and peak velocity to the first target. Vision condition and target size did not affect the time spent on the first target. These results suggest that preparation of the second movement is completed before the first movement is terminated. Experiment 2 examined when this preparation occurred. A full vision condition was compared to a condition in which vision was occluded during the flight phase of the first movement. Movement initiation times were shorter when vision was continually available. Total movement time was reduced with vision in two-target condition, but not in a control one-target condition. The time spent on the first target was greater when vision was not available during the first movement component. The results indicate that vision prior to movement onset can be used to formulate a movement plan to both targets in the sequence [Fischman & Reeve (1992).