An Event-related Potential Study Of Facial Expression Perception

Face is the most frequent thing in our life. Facialexpressions, as an important non-verbal intercoursemeans, are strongly associated with the socialcommunication and eavironment adaptation. This researchused the behavior and event-related potentials toinvestigate the response differences among the happy,angry, neutral faces and object pictures, hnd it used thepicture recognition paradigm and two experiments toinvestigate the face perception. The statistics wererecorded from the college students (13males, 12 females).The first experiment was to discriminate the expressionpictures and the non-expression pictures among 4 kindsof pictures (implicit facial expression processing).Happy and angry faces were expression faces; neutralfaces and object pictures were non-expression faces. Thesecond experiment was to decide whether face was happyor not between happy and angry faces (explicit facialexpression processing).We found that there were no significant differencesamong happy, angry and neutral face pictures' N170amplitude, but the amplitude of neutral facepictures' N170 was significantly higher than the objectpictures. The activation of N170 was earlier on the leftoccipitotemporal cortex. The face pictures were elicitedobvious late positive components in the parietal centralareas, from about 350ms to 750ms. The activation areas were from the posterior to the anterior areas. Besidesthat, the neutral faces elicited higher amplitude thanthe expression faces, and didn't find any significantdifferences between the happy and angry faces inexperiment one. The other experiment found happy faces'amplitude was much higher than the angry faces, only inthe first time window. Later on, there were no dramaticdifferences between happy and angry faces. There was aninversion effect between the two experiments: angryfaces elicited higher amplitude than the happy faces inthe first experiment, but the results reversed in thesecond experiment.The following conclusions could be drawn from theresearch: (1)N170 was correlated with the face-specificprocessing; (2)The facial expression processing'sdifferences were mainly among the late positivecomponents, and the implicit facial expressionsprocessing and the explicit facial expressionsprocessing had reversion effect.