Hemispheric differences in attentional orienting by social cues.

Research points to a right hemisphere bias for processing social stimuli. Hemispheric specialization for attention shifts cued by social stimuli, however, has been rarely studied. We examined the capacity of each hemisphere to orient attention in response to social and nonsocial cues using a lateralized spatial cueing paradigm. We compared the up/down orienting effects of eye gaze cues, arrow cues, and peripheral cues (change in luminance). Results revealed similar cueing effects in each visual field for nonsocial cues, but asymmetric effects for social cues. At both short (150 ms) and long (950 ms) cue-target intervals, gaze cueing was significant in the LVF, but not in the RVF. Thus, there is a right hemisphere bias for attentional orienting cued by social stimuli, but not for attentional orienting cued by nonsocial stimuli. This supports a theory of a separate neural system for socially cued orienting of attention, as well as a theory of separate parallel and simultaneous neural systems for attention in the two cerebral hemispheres.