Interaction Of Gaze Direction And Facial Information Without Awareness

Eyes are important organs for human to convey information.In social communication,the awareness of individual's gaze direction is of great significance to the understanding of psychological state and the prediction of behavior.Previous research have found that the processing of gaze direction and facial information(e.g.,Facial expression and facial attractiveness)were correlated with each other,which indicated that multifacet information can be integrated in the processing of facial information.Previous research about the integration mechanism of gaze direction and facial information(e.g.,facial expression and facial attractiveness)has not reached an agreement.The issue whether high-level configuration-information of face(such as eye direction,facial expression and facial attractiveness etc.)can be processed unconsciously has been contentious.Although different paradigms have been applied to explore unconscious processing of facial information,the following inadequacies still exist:(1)In terms of the research content,previous studies mainly investigated whether different facial information(gaze direction,facial expression,facial attractiveness)can be processed unconsciously,with few studies focusing on whether gaze direction and other facial information(such as facial expression and facial attractiveness)can be integrated and processed unconsciously.(2)In terms of research paradigm,previous research mainly adopted visual crowding paradigm,attention blink paradigm and visual masking paradigm.However,both visual crowding paradigm and attention blink paradigm have the disadvantage that stimulus cannot be kept totally unconscious in spite of the restriction of attention.With regard to the visual masking paradigm,although stimulus can be kept in totally unconscious condition,the duration of stimulus presentation is too short to allow unconscious processing of high level configuration-information.(3)In terms of research techniques,previous studies concerning unconscious processing of facial information mainly rely on behavioral index,namely,accuracy and reaction time.Results of behavioral studies can only answer whether or not facial information can be processed unconsciously,but not how facial information is processed in unconscious situation.Concerning the deficiencies of previous studies,the present study adopted continuous flash suppression paradigm(CFS),which allows stimulus in unconscious state for a long time.With the technique of event-related potentials(ERP),this study aims to explore the mechanism of integration processing of eye direction and facial information(facial expression and attractiveness)under unconscious condition.The present study attempts to explore the following four questions through conducting four studies and eight experiments respectively from two aspects,namely,gaze direction and facial expression(study 1,2),gaze direction and facial attractiveness(study3,4):(1)Whether gaze direction and facial information can be integrated and processed under unconscious condition?(2)If yes,whether the integration pattern of gaze direction and facial information is the same under different conditions of facial expression and facial attractiveness?(3)Whether the integration processing of gaze direction and facial information depends on the holistic facial information?(4)Whether gaze direction has independent processing mechanism in the processing of facial information?Study 1,by adopting b-CFS paradigm,attempted to investigate whether the integration of gaze direction and facial expression would influence the unconscious processing of face.Results showed that angry faces combined with direct gaze overcame suppression more rapidly than angry faces with averted gaze,which indicated that gaze direction and facial expression were integrated before individual's awareness(Experiment 1,2).Further studies were conducted to identify the neural correlates of the integration processing of gaze direction and facial expression under unconcious condition.It was found that the integration processing of gaze direction and facial expression occurred at an early stage of facial processing(Experiment 3).Study 2 investigated whether the integration processing of gaze direction and facial expression is dependent on the holistic facial information.Results showed that the information of gaze direction and facial expression could be integrated even when other facial information was removed and only the eyes region was remained(Experiment 4).Study 3 investigated whether the interaction of gaze direction and facial attractiveness would influence the unconscious processing of face.It was found that high attractive faces with averted gaze overcame suppression more rapidly than high attractive faces with direct gaze.No significant difference between low attractive faces with direct gaze and averted gaze was observed,which showed that gaze direction and facial attractiveness can be integrated before reaching consciousness(Experiment 5,6).The current research further identified the neural correlates of integration processing of gaze direction and facial attractiveness under unconscious condition.ERP components related to the interaction of gaze direction and facial attractiveness were found.However,the time window was rather short and only few brain regions were involved.In addition,under completely unconscious condition,the interactive effect of gaze direction and facial attractiveness emerged at a late stage(Experiment 7).Study 4,by employing time-frequency analysis,investigated whether the integration processing of gaze direction and facial attractiveness would modulate the amplitude of theta band.It was found that the integrated process of gaze direction and facial attractiveness occurred at an early stage of facial processing.In the processing of high-attractive face,direct gaze induced higher theta-band amplitude than averted gaze.On the contrary,in the processing of low-attractive face,averted gaze induced higher theta-band amplitude than direct gaze(Experiment 8).In conclusion,the above results suggested that gaze direction,facial expression and facial attractiveness can be processed under unconscious condition.Besides,the lack of awareness reduced the processing speed of the above three types of facial information and also the speed of integration processing of gaze direction and facial information.In addition,the present research found that the holistic facial information would interfere with the perception of gaze direction.The gaze direction and facial expression has a relatively independent processing mechanism in the processing of facial information.Different patterns were found in the integration of gaze direction and facial expression under the conditions of two threatening face expressions(angry and fearful).The information of facial attractiveness was processed at an early stage of facial processing.The information of gaze direction was integrated into the perception of high-attractive face and low-attractive face in different ways.The results of the present study supported the shared signal hypothesis,and provided revision for the model of distributed human neural system for face perception.