Effects Of The Face Expression And Different Gray Background On Pupil Size

In Emotional study, emotion elicitation is the important issue that concerns the experiment could develop successfully, and that the research could be well controled. The emergence of the standardization emotional stimulis seems to be enough helpful to resolve this problem. Facial expression photo is commonly used as visual material, which can be applied to cross-cultural research. Sketch type of expression faces can also decrease the impact of gender differences. Apart from being emotional stimuli, the face studies also include face recognition, face expression surveys. As applied research of face material developed fast, studies to the face expression are moving slowly. Studies about the relation of the facial expression and its emotional effects are rarely reported.In this study, happiness, anger, sad and fear—four categories of emotional expression of sketch faces were used as experimental material. Pupil size were used as the indicator of the visual effect. Objective of this study was to discuss the impact of different gray background on the face visual effect, and to search the interaction between the facial expression level and background gray level.Eye tracking system was used to record the pupil size. To validate eye movement recording of the pupil size can accurately reflect the emotional changes, pupil size was measured when volunteers were watching positive, negative and neutral type pictures. The result was that pupil size of positive and negative group were both significantly greater than the neutral group.Our study showed that two factors of different gray background and different type of emotionl face could impact the pupil size result, and proved the existence of the interaction between the gray level of background and the emotionl type of faces. Also the interaction between the gray level of background and the emotionl level of faces was found. All the result above indicated that gray background played a important role on face visual effect.In another experiment, 40 volunteers were told to choose the emotion type of the neutral emotional face with different gray background among happiness, anger, sad and fear. Results showed that different gray background influent recognition of the neutral face by different emotional classification tendencies. Gray background factors could affect face recognition.