Abstract
Observers distribute their attention to facilitate action. For example, attention is prioritized toward stimuli proximal to their hand if the hand is positioned near the display screen (perihand bias). In the present study (n = 108), using a target detection task, we examined whether the factors of response effector (hand vs foot) and body posture (seated vs standing) could affect the distribution of attention toward perihand space. Observers positioned their right hand near the right edge of the display screen, and the target stimulus could appear proximal or distal to the hand in simulated peripersonal or extrapersonal space. The results revealed a significant interaction between response effector and body posture. For hand-effector responses, the perihand bias was elicited for both seated and standing body postures. However, for foot-effector responses, the perihand bias was only revealed while in the standing body posture, not while seated. We concluded that attention appears distributed in an action-centered framework, with action affordances driving the perihand bias. These results have ramifications for affordance competition hypotheses and the interactive role of body posture with the task-relevant response effector.
