东西方面孔异族效应机理的电生理学证据

采取事件相关电位方法研究东西方面孔记忆编码的差异（DM效应），从而阐明异族效应的神经机制。14名被试学习和再认东西方面孔照片的实验结果表明，无论记住与否，西方面孔产生的早期成分（潜伏期70~220ms）在头皮额部有一个比东方面孔更为正向的变化，表明在此阶段更多的资源分配于异族面孔，支持异族效应产生的特征选择假说。无论东方面孔还是西方面孔，记住与未记住相比较，则在额部和顶部产生潜伏期在晚期正成分（LPC）范围的正走向变化，但西方面孔在240~320ms潜伏期范围内，DM效应较小。另外，东方面孔在枕部诱发出一个明显的负波N260，而西方面孔产生的N260很小甚至没有，反映了大脑对不同种族面孔的编码机制有所不同，因而可能被称为“种族特异波”

THE MECHANISM OF OTHER RACE EFFECT BETWEEN EASTERN AND WESTERN FACES REVEALED BY ELECTROPHYSIOLOGY STUDY

The difference of memory encoding on eastern and western faces (DM effect) and the neural mechanisms of other race effect were studied by using event-related potential (ERP) experiments. The present results showed that the early components (peak latency 70~120ms) at frontal scalp elicited by western faces have a more positive-going than those elicited by eastern faces regardless of recalling or not. This suggests that more resources are cost to other race faces in the early stage of processing, and thus supports the characteristic selective theory of other race effect. The late positive component (LPC) evoked by recognized faces is more positive-going than that by not memorized regardless of eastern or western faces. However, the DM effect elicited by western faces is smaller at the latency range 240 to 320 ms. Moreover, there is an obvious N260 at occipital area for the eastern faces, but none or very small N260 for the western faces. The N260 reflects the different encoding manner to different race faces in the brain and we are reasonable to call it “Specific Race Component”