The Brain Mechanism Of Other Race Effect: An ERP Study

Face recognition is one of the most important skills in our daily life. We usually have the sense that we perceive individuals belonging to "other races" (such as the Asians perceive Caucasian faces) as all looking alike. This commonly experienced all look alike illusion for other-race faces exists in different race crowds, and is named as other race effect (ORE). Many scholars make a comprehensive range of studies, and reach kinds of explanations, which get behavioral and neurophysiologic support. However, why other races all look alike has not been investigated by direct neurological evidence. The existed studies all approve that the distinctiveness of representations can be reflected by the amplitude of N270. Therefore, in this paper, using delayed matching-to-sample paradigm, we adopted an ERP experiment to investigate the neural mechanism of the other race effect by taking N270 as an index.This study included three experiments. Adopting a delayed match-to-sample paradigm, the first experiment investigated if there is difference between own race and other race faces in comparison stage reflected by N270. The second experiment further investigated whether the result of experiment one was caused by the low-level salience of different pictures. The third experiment validated the effectiveness of our indicator and paradigm.The main findings of this study are as follows:(1) N270 was elicited when faces were changed, regardless of their races. However, the N270 elicited by own race faces, had a more negative-going than that elicited by other race faces, and mainly appeared in the right hemisphere.(2) Reversing the faces had no effect on the low-level salience, but the ORE disappeared. The differences of N270 between own race and other race faces also disappeared with it. (3) It was effective that N270 could reflect the difference between the mental representations of faces.