The Neural Machanism Of The Own-group Bias And The Effect Of Group Size

The Own Group Biases (OGB) refer to the tendency to better recognize own-group than other-group. The own-race bias (ORB) or the tendency to better recognize own-race than other-race, is one of the best replicated phenomena in face perception. It is consistent across various racial/ethnic groups; it is generally replicable across studies; and it is also significant across different types of memory tasks. However, the ORB is only one of the OGB that has recently been observed in face recognition. There are some other similar phenomena reflect the OGB, such as own-gender bias, own-age bias, own-sexual orientation and so on. The explanations of the OGB originated from the theoretical models that explain the ORB. The present research attends to explore the neural machanism of the OGB and the effect of group size.By using event-related potentials(ERP), the present study provided electrophysiological evidence that mere social categorization is sufficient to elicit in-group face recognition advantage. We excluded the effect of perceptual expertise and used traditional facial learning-recognition paradigm in this research. Consistent with predictions, participants recognized in-group faces more correctly and rapidly than out-group faces. This indicated the own-group bias (OGB) in face recognition is an effect that can be generally repeated across cultures. The ERP results showed that in learning phase, more negative N100 was observed for in-group relative to out-group faces. Compared with in-group/hits, N170 and VPP were enhanced for out-group/hits in recognition phase. The results indicated that the OGB occurred not only in the encoding stage, but also in the retrieval stage of memory.In the second part of our study explored the effect of group size on the OGB in both minimail-group and natural-group.In minimail-group, the OGB in minority group was significant,but was not significant in mojority group.In natural-group, the OGB was more significant in minority group than mojority group. The result indicated that the group size would affect the OGB, and the minority group was more likely to exibit the OGB.