大脑两半球与整体和局部性质的选择性加工

HEMISPHERE ASYMMETRY AND SELECTIVE PROCESSING OF GLOBAL AND LOCAL PROPERTIES

研究大脑两半球在加工整体和局部性质中的优势以及两半球能否同时分别选择两个复合刺激的整体和局部性质。实验中把一个复合字母随机呈现在左视野或右视野 ,或者把两个复合字母同时分别呈现在左视野和右视野。实验一发现 ,在单侧呈现条件下 ,被试检测左右视野的整体或局部靶目标的反应时没有显著差别 ,但在双侧同时呈现条件下 ,检测右视野局部靶目标比检测左视野局部靶目标时的反应时短。实验二要求被试检测同时呈现在左右视野的整体或局部靶目标 ,发现当两个视野的靶目标处于同一水平时 (整体或局部 )反应时较短 ,两个视野的靶目标处于不同水平时 (一侧处于整体水平而另一侧处于局部水平 )反应时较长。这些结果提示 ,当两个复合刺激同时呈现在左右视野时 ,大脑左半球在选择性加工局部性质时具有优势 ;左右两半球更容易选择两个复合刺激同一个水平的性质 ,分别选择两个复合刺激不同水平的性质比较困难。

The current study examined the hemisphere asymmetryic advantage of selective processing of global and local properties and whether the two hemispheres are able to select simultaneously the global property of one compound stimulus and the local property of another compound stimulus. We presented one compound stimulus randomly in the left or right visual fields or two compound stimuli simultaneously in the left and right visual fields, respectively. Experiment 1 showed that reaction times (RTs) to global or local targets did not differ between the left and right visual field stimuli in the unilateral presentation condition. However, RTs to local targets were shorter to the right than left visual field stimuli in the bilateral presentation condition. In Experiment 2 subjects detected global or local targets that appeared in both hemifields. We found that RTs were shorter when targets appeared at the same than different levels of compound stimuli presented simultaneously in both hemifields. The results suggest a left hemisphere advantage in local processing in the bilateral presentation condition. Moreover, it is easier to select targets at the same than different levels of two compound stimuli simultaneously presented bilaterallyin two hemifields.