Fig. 1.

Behavioral paradigm. A: arrangement of targets and starting positions in each workspace. Reaches were made from each of 3–4 starting positions to each of 3–4 targets. Initial hand positions were always in the same (middle) row, and targets were either above or below the array of starting positions. In this plot, only required reaches to the upper leftmost target are illustrated. B: sequence of events on a single trial. Two reaches were performed: on no hand vision trials (shown), the first reach served to define the initial hand location for the second reach in such a way that somatic and visual information were never simultaneously available. The sequence of events was identical on concurrent hand vision trials, except that a visual stimulus was present at the starting position after completion of the first reach.