Hand Position Affects Perceptual Grouping

Over the past decade evidence has accumulated showing that performance of attention, perception, and memory related tasks are influenced by placing the observer's hands near the stimuli. Two theories have been proposed to account for these effects. The attentional account holds performance is altered due to changed attentional prioritization of hands-proximal space, while the differential pathways hypothesis holds processing of stimuli near the hands is dominated by the magnocellular visual pathway resulting in the variety of documented effects. Here we test whether perceptual grouping processes are inhibited in hand-proximal space. Consistent with previous work on object-based attention, we find a benefit for the visual object in the hands-distal, but not the hands-proximal, condition suggesting perceptual grouping is impaired near the hands. This change in perceptual grouping processes cannot be explained solely by an attentional account of visual processing changes near the hands.M.A