Facial Expression Processing Under Different Perceptual Loading

Facial expression is an important emotional stimulus in interpersonal communication.When individuals process faces,they are often accompanied by other perceptual tasks.At this time,attention resources are limited.Previous studies have explored the processing of threatening emotions,such as anger and fear,under perceptual load tasks,but not disgust,which is also a threatening emotion.Similarly,how are non-threatening sad faces processed under perceptual load tasks? In addition,how are the surprise and neutrality of ambiguous valence processed under different perceptual loads? In this study,we manipulated the perceptual load by controlling the length difference between two bars on the face,and used ERP techniques to explore the temporal dynamic characteristics of facial expression processing under different perceptual loads.Experiment 1 investigated the processing of threatening negative facial expressions under different perceptual load.The facial emotions were neutral,fear,anger and disgust.Behavior data showed that compared with low load,high load produced shorter response time and higher accuracy,and the accuracy under neutral expression was greater than disgust and fear,but had no difference with anger.Meanwhile,under high load,neutral accuracy was significantly greater than fear,but had no difference with anger and disgust.The ERP results showed that under low perceptual load,fear and anger induced a larger N170 amplitude than neutral load,but did not differ from disgust,while under high perceptual load,there was no such effect.In addition,the low load induced a larger LPP amplitude than the high load,and only in disgust did the low load induced a larger LPP amplitude than the high load.In Experiment 2,we investigated the processing of non-threatening negative facial expressions under different perceptual loads,including neutral and sad facial emotions.The result showed that the response time was shorter and the correct rate was higher under low load,and the correct rate of neutral was higher than that of sadness under high load.ERP results showed that sadness induced N170 amplitude was larger than neutral,and was not regulated by perceptual load.LPP component showed that the amplitude under low load was significantly greater than that under high load.Experiment 3 investigated the processing of ambiguous valence facial expressions under different perceptual loads.The facial emotions included neutral and surprise.The result showed that the response time was shorter and the correct rate was higher under low load.The ERP results showed that the P1 amplitude of low load was larger than that of high load.Compared with neutral load,the N170 and EPN amplitude induced by surprised expression was larger.The LPP component showed that the P1 amplitude of low load was significantly greater than that of high load.In conclusion,the following conclusions can be drawn from this study:(1)Compared with fear and anger,there was an opposite attentional processing pattern for disgust expressions,but this phenomenon only occurred under low perceptual load;(2)Under different perceptual load,the processing of sad expression only affected the task accuracy,but it was not adjusted at the electrophysiological level;(3)Compared with neutral expression,surprised expression requires more attention resources and is not regulated by perceptual load.