THE primate visual system is adept at identifying objects embedded within complex displays that contain a variety of potentially distracting elements. Theories of visual perception postulate that this ability depends on spatial selective attention, a mechanism analogous to a spotlight or zoom lens, which concentrates high-level processing resources on restricted portions of the visual field1,2. Previous studies in which attention was pre-cued to specific locations in the visual field have shown that the spotlight has a single, unified focus2,3, even in the disconnected hemispheres of patients who have undergone surgical transection of the corpus callosum4,5. Here we demonstrate that an independent focus of attention is deployed by each of the surgically separated hemispheres in a visual search task, such that bilateral stimulus arrays can be scanned at a faster rate by 'split-brain' subjects than by normal control subjects. The attentional system used for visual search therefore seems to be functionally and anatomically distinct from the system that mediates voluntary orienting of attention.
|Original language||English (US)|
|Number of pages||3|
|State||Published - 1989|
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