Influence de la préparation d’une atteinte manuelle sur l’orientation initiale de l’attention lors d’une tâche de recherche visuelle

This paper deals with the links between spatial attention and reaching movement's motor preparation. During a visual search task, participants prepare to manually reach a button of the numeric keypad and execute it when they find an intruder on the screen. The experimental devices allowed us to control two directions: on the one hand, the direction of the response button's manual reach (on the horizontal plane) and on the other hand, the direction of the intruder's direct attentional reach, starting from the fixation point (on the vertical plane). The results show that: (a) reaction times are shorter when there is a directional congruence between these two directions than when there is incongruence; (b) this effect is significant when attention is voluntarily shifted, whereas it is no longer significant when attention is automatically captured by an intruder. These results suggest that visual search's initial direction is determined by the prepared manual reach. These data are discussed in the premotor theory of attention's framework.