Right hand presence modulates shifts of exogenous visuospatial attention in near perihand space.

To investigate attentional shifting in perihand space, we measured performance on a covert visual orienting task under different hand positions. Participants discriminated visual shapes presented on a screen and responded using footpedals placed under their right foot. With the right hand positioned by the right side of the screen, mean cueing effects were significantly greater for targets presented on the right compared to the left side, at the shortest stimulus onset asynchrony. The right hand still affected attention when the left foot was used to respond and when the right hand was crossed over the midline, indicating that this effect is not restricted to the right hemifield and cannot be accounted for by greater stimulus-response compatibility with the right (responding) foot. These experiments provide preliminary evidence that the presence of the right hand can modulate shifts of visual attention but emphasise the importance of stimulus-response compatibility effects in such investigations. Copyright 2010 Elsevier Inc. All rights reserved.