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Abstract

Numerous everyday activities require individuals to make rapid movements to specific locations in space (e.g., pointing, reaching and grasping, catching). Although it is generally accepted that vision plays an important role in both the control and acquisition of goal directed movement, it is still not fully understood how vision is used and in what way its role changes as a function of practice. There were two primary goals of the present research. The first was to examine how the reliance on visual feedback in the control of rapid aiming movements changes with practice. The second was to investigate how participants adapt control strategies to optimize performance under different visual feedback conditions. Three experiments were conducted in which we examined (1) the influence of visual feedback on the centrally planned initial impulse and feedback-based error correction phases during acquisition; and (2) the effect of removing visual feedback at different levels of practice. The results indicated that in both the acquisition trials and transfer tests, vision had a major impact on the spatio-temporal properties of the initial impulse and error correction phases. It is proposed that learning involved a dual process of improved programming and increased efficiency of feedback processing. Within this framework, practice not only acted on programming and feedback processes directly, but also indirectly through a reciprocal interplay between both processes. On one side, improvements in the programming of the initial impulse decreased the frequency of error correction phases and facilitated the efficiency of the correction process. On the other side, the proficiency to utilize sensory information influenced the programming of the initial impulse. When participants had visual feedback, they planned their movements to use this effective source of information. As a result, the reliance on visual feedback processing remained even after extensive levels of practice. When visual feedback was not available, movements were planned to minimize the need for sensory-based error correction.