Abstract
Previous studies indicated that saccade latencies are affected by the spatial compatibility between the target position on the screen and the position of a static hand. Further, the modulation of saccade latencies depended on the delay between fixation point offset and target onset. With a 0-ms delay, saccades were slower toward a target close than opposite to the hand location (eye-hand proximity interference), while the opposite pattern was found for a 1000-ms delay (eye-hand proximity facilitation). Time-consuming competition for attentional processes between eye and hand were evoked to account for these results. In the present study, we opposed a code occupation hypothesis (COH) to this attentional explanation. According to COH, once a code is bound to a current action, all other access to this code will be temporarily delayed. We varied the target location with respect to the hand. The hand was laid at a fixed location on the left or right and the target was presented at different eccentricities to the left or right of the screen center. The results indicated that the saccadic modulation did not depend on the spatial proximity between the hand and the target. Rather, similar eye-hand interference (0-ms delay) and facilitation (1000-ms) were found for all targets sharing the same hemi-space as the hand. In agreement with the code occupation hypothesis, the saccadic modulation in the presence of a static hand depended on whether the saccade shared or not the hand-related action code.