Abstract
Perception, attentional control, and working memory are remarkably influenced by the proximity of the hands to viewed objects. For example, items near the hands receive perceptual, attentional, and memorial priority relative to other objects in the environment. Nevertheless, it remains unclear what mechanism underlies these effects. Here, we propose that the priority given to information near the hands arises because (1) attention is less susceptible to interference from information outside of hand-space, and (2) voluntary shifts of attention between dimensions on which objects may be analyzed (e.g., global shape, local elements) are relatively slow and inflexible near the hands. We tested this hypothesis in two studies. In Study 1, participants performed an Eriksen-type flanker task while holding their hands either around the target, such that the flankers appeared outside of hand-space, or with their hands off to the side and thus not around any of the stimuli. We found that flanker interference was substantially reduced when the hands were held around compared to not around the target. A control condition confirmed that this reduction in interference was not observed when non-hand physical barriers were placed between the target and flankers. In Study 2, participants analyzed objects according to their global shape or local elements while holding their hands near to or far from the objects. Across subsequent objects, participants either maintained the same attentional scope or switched between global and local processing. We found that switches between global and local processing were markedly slowed near the hands. Together, these findings indicate that previously observed alterations in visual processing might be attributed to a mechanism of attention that is resistant to intrusions from external information and to effortful shifts of attention, thereby allowing observers to more deeply "lock in" to processing of objects within the hands.
Meeting abstract presented at VSS 2012