The Cognitive Neural Mechanism Of Positive Classification Advantage Of Facial Expression:Behavioral And Electrophysiological Evidence

Generally,faces with positive expressions were classed more correctly and quickly than faces with negative expressions such as sad,fear,and angry,which is also known as positive classification advantage(PCA).This phenomenon has been widely confirmed by behavioral experiments.To date,however,few studies explored the cognitive neural mechanism underlying the PCA.Previous studies have suggested that the PCA effect is based on configural processing,and face inversion will affect the configuration processing of faces.Face inversion is considered to be a specific indicator of configuration processing and is widely used in many studies.Therefore,this study inverted the face pictures,and systematically studied the classification characteristics of happy expressions and sad expressions under the condition of upright and inverted faces through behavior and electrophysiology,so as to explore the cognitive neural mechanism of positive expression classification advantages.The paper includes three studies,behavioral research of facial expression classification,event-related potential research and neural oscillation research.In study 1,a 3(expression: happy,neutral,sad)× 2(direction: upright,inverted)two-factor within-subject design were used to record and analyze the response time,accuracy,ERP and EEG of the subjects.The results of behavioral research showed that happy faces were classified faster than sad faces under upright conditions,while the PCA effect disappeared under inverted conditions,and there was no significant difference in the classification accuracy between sad faces and happy faces.Because face inversion affects the configuration processing of faces,the dominant faces of positive expression classification exist under upright conditions and disappear under face inversion conditions,which indicates that the processing method of PCA is mainly configuration processing.Study 2 by analyzing the amplitude and latency of ERPs components,it was found that EPN and N170 had longer latency under inverted conditions,indicating that the configuration processing of upright faces mobilized more cognitive resources and made the classification of happy faces faster,while the configuration processing of inverted faces affected the classification of faces,which required more time;At the same time,ERPs components were active in the temporal occipital region,indicating that the temporal occipital region was involved in the PCA effect.In study 3,EEG time-frequency analysis found that expression classification induced significant theta band activity,and sad faces induced stronger theta activity than neutral faces,suggesting that sad faces caused stronger cognitive activity,and theta is related to emotional face processing.Moreover,there was no significant difference in theta band activity induced by happy faces and sad faces,and there was no significant difference in theta band activity induced by the placement direction of faces,indicating that theta activity(Induced)may not be related to the PCA effect.