卡通面孔分类与知觉加工的ERP比较研究

A Comparative Event-related Potential Study on Cartoon Face Classification and Perception Processing

通过ERP方法,考察卡通面孔分类(人和动物)的脑机制及其与卡通面孔知觉(人与车)的差异。结果表明,分类任务中,动物面孔VPP潜伏期显著长于人,N170波幅半球效应显著,LPP波幅在顶叶和中央区最大;分类任务VPP和LPP波幅均显著大于知觉任务。结论:卡通面孔分类比面孔知觉速度慢、强度大,消耗心理资源多。顶叶和中央区可能是执行分类任务的主要脑区,且加工人类面孔具有速度优势。面孔加工中结构编码与特征编码可能部分是并行的。

The ERP technique was used to study the brain mechanism of cartoon face classification processing, and to investigate the differences between cartoon face classification and perception processing. The cartoon face classification experiment： All the volunteers （ aged from 18 to 23 ） were right - handed and had normal vision or corrected vision. None of them were color - blinded or had any his- tory of mental illness. A total of 450 human and animal cartoon faces were used as stimuli. A 32 - channel EEG was recorded at a sam- piing rate of 1000Hz using averaged mastoids reference by the Neuroscan EEG acquisition system. The amplitude and latency of N170 （ T5, T6）, VPP （Cz） and LPP （ F3, Fz, F4, FC3, FCz, FC4, C3, Cz, C4, P3, P2, P4, O1, O2 and O2 ） components were obtained by off - line analysis. Behavioral data and ERP data were analyzed by SPSS 13.0 through multivariate repeated measure of ANOVA. The results： The reaction time （RT） for human faces was significantly shorter than the RT for animal faces. RT for square faces was significantly shorter than those for round faces and triangle faces. RT for females was shorter than RT for males. The amplitude of VPP of square faces was significantly larger than those of round faces and triangle faces. RT for animals was significantly longer than RT for humans, and VPP latency of girls was significantly shorter than VPP latency of boys. The amplitude of N170 showed right hemi- sphere dominance in face classification; the average amplitude of LPP in parietal lobe and central area were larger than those in frontal lobe, post frontal area and occipital lobe. The cartoon face perception experiment： Participants were the same as those tested in the classification experiment. In total, 50 human cartoon faces and 50 car cartoon pictures were used as stimuli. The subjects＇task was to tell if the picture was about a car or a face. Data recording and analysis were the same as used in the previous experiment. The results： The RT of perception task was significantly shorter than that of classification task; N170 showed right hemisphere dominance in face classification; the amplitudes of VPP and LPP of perception task were significantly lower than those of classification task ; the VPP latency of females was shorter than that of males ; the average amplitude of LPP in parietal lobe and central area were lar- ger than those in the frontal lobe, post frontal area and occipital lobe. The conclusion： Face classification processing in the brain is slower and stronger than the perception processing, which may be be- cause the former processing needs more psychological resources. People are better at processing human faces than animal faces. Parietal lobe and central area are probably the principal brain regions for face classification processing. Females have an advantage over males in face processing speed. Structural coding and feature coding may be parallel during the face processing. LPP is an important indicator to reflect face classification processing.