Abstract
Attention operates in the space near the hands with unique, action-related priorities. Here, we examined how attention treats objects on the hands themselves. We tested two competing hypotheses. First, attention on the hands may exaggerate action-related priorities (e.g. faster detection of on-hand stimuli), as though the surface of the hands is the proximal case of near-hand space. Alternatively, we proposed the body boundary hypothesis: Attention should be biased to avoid orienting toward the hands (in order to remain entrained to near-hand space). We employed a spatial cueing paradigm to assess how attention is deployed to the surface of the hands. Stimuli were projected onto participants’ hands such that detecting invalidly cued targets required shifting attention across the surface of the hands. We observed a delayed orienting of attention from near-hand space to the hand (Experiments 1A & 1B) and from hand to hand (Experiment 2). In contrast to typical findings in object-based attention, this delayed orienting also occurred when shifting attention within the space occupied by a hand (Experiment 3). Finally, we show that grasping a tool induced delayed orienting to the end of the tool, as though it were incorporated into the body boundary (Experiment 4). These results support the body boundary hypothesis. We suggest that the body boundary could assist the guidance of action by making attention predisposed to avoid orienting toward the hands and instead toward near-hand space, where the targets of actions are usually located.
Meeting abstract presented at VSS 2013