The role of peripheral and central visual information for the directional control of manual aiming movements.

Seeing one's hand in visual periphery has been shown to optimize the directional accuracy of a sweeping hand movement, which is consistent with Paillard's (1980; Paillard & Amblard, 1985) two-channels model of visual information processing. However, contrary to this model, seeing one's hand in central vision, even for a brief period of time, also resulted in optimal directional accuracy. One goal of the present study was to test two opposing hypotheses proposed to explain the latter finding. As a second goal, we wanted to determine whether additional support could be found for the existence of a visual kinetic channel. The results indicated that seeing one's hand in central vision, even for a very short delay, resulted in the same accuracy as being permitted to see one's hand for the duration of the whole movement. This suggests that seeing one's hand around the target might enable one to code its location and that of the target within a single frame of reference and, thus, facilitate movement planning. In addition, the results of the present study indicated that seeing one's hand in motion while in visual periphery permitted a better directional accuracy than when this information was not available. This suggests that the movement vector, which is planned prior to movement initiation, can be quickly updated following movement initiation.