Guided Visual Search Is a Left-Hemisphere Process in Split-Brain Patients
作者研究了裂脑（胼胝体切断）患者的视觉搜索能力。此前研究发现，当视觉刺激均匀分布在左右视野时，裂脑患者的搜索速度是正常人的两倍，仿佛每个半球都有独立的注意扫描系统。本实验对3名裂脑患者进行测试，发现将搜索限制在相关子集的能力（即引导搜索）仅存在于左半球，右半球即使搜索速度更快也无法完成引导搜索。正常对照者的两个半球均能进行引导搜索。这表明，像语言等高级认知过程一样，策略性视觉空间注意过程也优先偏侧化于左半球；胼胝体在正常人右半球的引导搜索中起中介作用。
Previous research has shown that split-brain (callosotomy) patients search through visual displays twice as fast as normal observers when items are divided evenly between visual hemi-fields, as though each disconnected hemisphere possessed its own attentional scanning system (Luck, Hillyard, Mangun, & Gazzaniga, 1989, 1994) Results from 3 split-brain patients in the present study indicate that the ability to limit search to a relevant subset of the visual display is lateralized to the left cerebral hemisphere This ability to perform guided search was not shown in the right hemisphere, even when the search time in that hemisphere was superior to search time in the left Furthermore, guided search was observed for both hemifields in normal control observers These findings suggest that, as with higher cognitive processes such as language, strategic visuospatial attentional processes are preferentially lateralized to the left cerebral hemisphere The findings also imply that the callosum mediates guided search in the right hemisphere of normal subjects