How Pointing Informs Visual Search

Pointing gestures are commonly used to guide the attention of others to objects in the environment, such as an animal hidden in the landscape. This raises the question of how another person's pointing gesture informs the visual search for the referent. We tested the hypothesis that pointing gestures are perceived as marking regions of space that define where participant search for the referent. In three experiments, participants searched for a pointed-at target object that was embedded among distractor objects arranged with different spatial densities while eye movements were tracked. Participants searched in a restricted region surrounding the position they perceived as pointed-at. However, the sizes of the searched regions depended considerably on the density of the search display, refuting the hypothesis that pointing gestures strictly mark the to-be-searched region. In addition, participants sometimes scanned objects that they would not even consider as pointed-at. We suggest that a flexible time-correlated criterion or a hybrid spatiotemporal criterion determines the sizes of the searched region. In summary, even if a pointing gesture was perceived as indicating a region of the search display, it has either a relatively weak or no effect on the size of the region that is eventually searched.