Embodied Cognition and Peripersonal Space
The idea of embodied cognition emphasizes the role of action in visual perception and attention. So, assuming the purpose of vision is to inform action planning, then it is possible that action-relevant cues in the environment may be more attentionally salient (implicit or explicit).
My former advisor Bruce Bridgeman and I investigated how actions, such as pointing (finger) and grabbing (entire hand), can alter the way we perceive the visual scene by creating a stronger attentional engagement (a phenomenon originally discovered by Catherine Reed, 2006, and Richard Abrams, 2008). Intending to perform an action also works similarly (Tseng et al., 2010 Perception). Interestingly, this attentional engagement helps people encode more information from a scene, but disappears when one's hand(s) can no longer touch the display (Tseng & Bridgeman, 2011 Exp Brain Res).
My good friend (and incredible colleague) Chris Davoli and I together have organized a Research Topic for this hand effect in Frontiers in Psychology, which includes 12 articles from 34 researchers who represent 23 institutions worldwide. For more information, or a free download of the e-book, please take a look at the Frontiers webpage: Taking a hands-on approach: Current perspectives on the effect of hand position on vision.
Tseng, P., Yu, J., Tzeng, O.J.L., Hung, D.L., Juan, C.H. (2014) Hand proximity facilitates spatial discrimination of auditory tones. Frontiers in Psychology, Perception Science, 5:527. [PDF]
Tseng, P., Bridgeman, B., Juan, C.H. (2012) Take the matter into your own hands: A brief review of the effect of nearby-hands on visual processing. Vision Research, 72, 74-77. [PDF]
Tseng, P., Bridgeman, B. (2011) Improved change detection with nearby hands. Experimental Brain Research, 209, 257-269. [PDF]
Tseng, P., Tuennermann, J., Roker-Knight, N., Winter, D., Scharlau, I., Bridgeman, B. (2010) Enhancing implicit change detection through action. Perception, 39, 1311-1321. [PDF]