The Effect Of Face Orientation And Face Gender On Emotional Lateralization: Evidence From The Chimeric Face Paradigm

Objective: The ability of the two hemispheres in face processing is different. Study on emotional faces has an important significance for human survival and development.However, there is no agreement to current study results The present study explores the functional differences between the two hemispheres in processing emotional faces using the chimeric face test, especially for processing the face direction and gender.Methods: In the chimeric face test, pairs of faces were presented, one above the other, with one showing emotion in the left half face and the other showing emotion in the right half face. It is to test 110 college students, with 50 males and 60 females. The experiment adopts a multi-factored design with 2 Face Orientation (Upright, Inversion) ×2 Face Gender (Male, Female) ×4 Emotional Type (Happy, Sad, Surprise, anger). Participants had to decide which face is more emotive.Results: (1) When presenting all four upright versions of the male and female chimeric faces, participants tend to pick the face that emotional expression presented in the left visual field, and they significantly had a faster response than the right visual field decisions.But, when presenting all four upright versions of the male chimeric faces, these were no differences in the left visual field (right hemisphere) bias. When presenting all four upright versions of the female chimeric faces, these were differences in the left visual field (right hemisphere) bias, and sadness had a greater left visual field (right hemisphere) bias than happiness, surprise and anger. (2) When presenting all four inverted versions of the male and female chimeric faces, participants tend to pick the face that emotional expression presented in the right visual field, and they had a faster response than the left visual field decisions, but not significant. However, when presenting all four inverted versions of the male chimeric faces, these were differences in the right visual field (left hemisphere) bias.and happiness had a greater right field (left hemisphere) bias than sadness, surprise and anger. When presenting all four inverted versions of the female chimeric faces, these were differences in the right visual field (left hemisphere) bias, and happiness had a greater right field (left hemisphere) bias than anger, surprise had a greater right field (left hemisphere)bias than sadness and anger. (3) This study found that in general, laterality quotients and reaction time bias were significantly positive correlation. That is if an individual had a greater left visual field bias, then his choice was faster to emotion presented in left visual field. If an individual had a greater right visual field bias, then his choice was faster to emotion presented in right visual field. And in regression analysis, laterality quotients could significantly predict reaction time bias.Conclusions: (1) In processing facial emotions, all four upright versions of the chimeric faces have a significantly left visual field (right hemisphere) bias, all four inverted versions of the chimeric faces have a significantly right visual field (left hemisphere) bias. The findings of this study provide support for the hypothesis that each hemisphere is differently specialized for processing of facial information. That is right hemisphere has an advantage in structure processing and the left hemisphere has an advantage in the characteristics processing. And this pattern has been supported by studies of face recognition. (2) In all four upright versions of the male chimeric faces, the face gender information doesn't impact the structure processing, but in all four upright versions of the female chimeric faces, the face gender information impacts the structure processing, and sad female face has a greater processing advantage in right hemisphere. In all four inverted versions of the male chimeric faces, the face gender information impacts the characteristics processing,and happy male face has a greater processing advantage in left hemisphere. In all four inverted versions of the female chimeric faces,the face gender information impacts the characteristics processing, and happy and surprise female faces have a greater processing advantage in left hemisphere. (3) This study has found that there is a positive correlation between the two measures of asymmetric bias in the chimeric faces test - laterality quotients and reaction time bias. This analysis suggests that both laterality measures provide concordant asymmetry results.