Cognitive And Neural Mechanism Of Self-advantage In Face Recognition

To distinguish the self from others is a fundanmental cognitive ability for human beings and crucial for conducting appropriate social communication. Individuals generally have stable self-advantages, one of examples of which is an advantage of self-face percpetion. That is, the individuals response to own faces more fastly and accurately than those to the faces of others, which is called self-advantage effect in face recognition.Although there is considerable evidence that self-face has an advantage relative to others’faces in face perception and recognition, it remains unclear which factor(s) contributes to such advantage. To answer this issue is key to understanding the nature of self-face perception. A typical account of the effect is that self-face with a biological and sociological properties as the salient stimuli relative to others’faces automatically attract one’s attention, facilitating the self-face processing or interfering with other tasks.In this thesis, we proposed the self-reference frame is key to the occuring of self-advantage effect in face recogniton. In object recognition, the relationship between agency and targets include processing objects from self-reference frame and other-reference frame, and the former have a higher performance than the latter. To test this hypothesis, four studies were carried out, we explored the cognitive and neural mechanisms of self-face advantage by using behavior, ERPs and fMRI techonology.In study 1, we reported two experiments to assess the role of the self-reference frame in the self-advantage by manipulating the judgment-reference frame (self- vs. other-reference) and the attentional level (exp.1 explicit face-recognition task vs. exp.2 implicit face-perception task). The results showed that the self-advantage effect resulted from a self-reference frame in either explicit face-recognition or implicit face-perception task. In contrast, such self-advantage was eliminated in the other-reference frame in both explicit and implicit face perception. The findings indicate that self-advantage effect benefits from a self-reference frame, independent of the face contexts.Since the self-reference frame facilitates the processing of self-face, whether it could facilitate the processing of others’faces? The two experiments (exp.3 and exp.4) in study 2 added another kind of face stimuli which was taken from the back of individuals when the face was turned from the front to back, to examine if the trun-back face would reduce the self-advantage effect. The results showed that, the self-advantage effect was found in mirror face condition(the same face stimuli as study 1), but not in turn-back face condition in explicit task(exp.3). And in implicit task of exp.4, there was no self-advantage effect neither in the mirror nor in the turn-back face condition. The findings indicate that the disappeared self-advantage effect results from the facilitating of self-reference frame to familiar turn-back face.The results in study 1 and study2 indicate that, self-advantage effect benefits from self-reference frame which may facilitate not only the processing of self-face, but also the processing of self-irrelevant information such as familiar faces. Moreover, the self-advantage effect was not irrelavant to the attentional levels.To further prove the neural mechanisms of self-advantage effect benefits from self-reference frame, we explored the time course of face processing by using ERP in study 3 (exp.5 and exp.6). Exp.5 showed that self-face advantage on the one hand owing to the propersities of stimulus itself, while modulated by judgment-reference frame. For further evidence, Exp.6 employed the turn-back face to explore its temporal processing features, the results showed the differece wave between self and famialir face was significant both in mirror face and turn-back face condtition, the self sense in face processing plays a key role to the occurrence of self-face advantage effect.In Study 4 (exp.7), we performed an event-related functional magnetic resonance (fMRI) to further identify brain regions involved in self-face advantage effect. The participants were asked to judge the face orientation from self-reference or other-reference frame. Compared with the familair face, activation selective to the self face was observed in the bilateral anterrior frontal gyrus and inferior frontal gyrus, the right middle frontal gyrus, inferior parietal lobule, precuneus, anterior cingulate gyrus, as well as left insula in self-reference frame condition, while only left insula in other-reference condition, the results indicate that self-reference frame plays a key role in self-face processing. Moreover, the interact contrast between judgment-reference frame and self-relevance showed the activation in the right medial frontal gyrus , anterior cingulate, sub-gyrus and left cuneus, of which regions may be involved in self-face advantage effect.In summary, self-reference frame determines the emergence of self-face advantage, and we separated the neural substrates of self-face advantage effect from other regions involved in self-face processing by manipulating the judement-reference frame. The brain regions involved in self-face advantage effect reflects the unique of self-face , also revealed the nature of self face processing, which plays a significant contribution to the self-awareness inquiry.