羞怯与非羞怯大学生在早期面孔加工中的差异——来自ERP的电生理学证据

Differences in Early Face Processing between Shy and Nonshy Undergraduates:Electrophysiological Evidence from an ERP Study

羞怯与社会认知密切相关,而面孔识别是人们社会生活中的一项重要的社会认知功能。目前关于羞怯的电生理学研究大多关注表情的效价效应和面孔的新旧效应对羞怯个体面孔加工的影响,却忽视了羞怯个体在基本的面孔识别能力——面孔-物体识别中可能存在的认知神经差异。因此,本研究采用ERP技术,使用GO/Nogo范式的面孔-物体识别任务,对17名羞怯大学生和17名非羞怯大学生在面孔结构编码中的N170成分进行考察,以期发现不同羞怯水平大学生在早期面孔加工中的认知神经差异。本研究发现,非羞怯大学生对面孔结构具有加工优势,识别面孔时,非羞怯大学生的N170波幅显著大于羞怯大学生的N170波幅,识别物体时则不存在组间差异;N170是面孔识别的特异性成分,面孔诱发的N170波幅显著大于物体诱发的N170波幅;识别面孔时,N170表现出大脑右半球的加工优势。

Shyness refers to individual＇s behavioral inhibition in social situations and a fear for negative evaluation in social situations which is closely associated with social cognition.Face recognition is an important type of social cognitive abilities in social life.In recent years,the majority of the neurophysiologic studies on shyness have focused on the effect of expressional valence and facial new-old effects upon face processing of shy individuals.It has been found that shyness predicted significantly smaller N400 amplitudes in response to anger and to a neutral expression （Marco,et al.,2005）.In addition,it has also been reported that there existed greater functional MRI signal response within the amygdala to novel than to familiar faces among healthy young adults who were originally categorized as behaviorally inhibited and temperamentally shy in early childhood （Schwartz,Wright,Shin,Kagan, Rauch,2003）.Shy adults exhibited greater bilateral amygdala activation during the presentation of strange faces and greater left amygdala activation during personally familiar faces than their bold counterparts （Beaton,et al.,2008）.Although these results revealed that shy individuals and nonshy individuals had cognitive and neural differences in facial expression recognition and old-new face recognition,whether there exist cognitive and neural differences in the basic face recognition ability （e.g.,face and object recognition） between shy and nonshy individuals remains an issue to be examined.This study investigated into N170 component via the face-object recognition tasks in order to explore the neurophysiologic differences in the early face processing between shy and nonshy undergraduates.The subjects were 17 shy undergraduates and 17 nonshy undergraduates.The major findings of the present study were：（1） the level of shyness interacted significantly with the types of stimuli,with the N170 amplitude of shy undergraduates being greater than that of nonshy undergraduates in face recognition,but this difference did not exist in object recognition.（2） There existed a significant effect of types of stimuli,such that the N170 amplitude elicited by face images was higher than that elicited by object images,and the N170 latency elicited by face images was shorter than by object images.（3） There was significant interaction between the hemispheres of the brain and the types of stimuli.Compared with left hemisphere,the N170 amplitude of right hemisphere was greater in face recognition,but the difference wasn＇t significant between left and right hemisphere in object recognition.The findings of this study suggest that nonshy undergraduates have processing dominance in facial configuration,and the N170 amplitude of the nonshy undergraduates is greater than that of the shy undergraduates in face recognition.N170 is the special component in face recognition.The right hemisphere manifests processing dominance in N170 in face processing.