Dynamic Face Movement Texture Enhances the Perceived Realism of Facial Expressions of Emotion

Most socially interactive virtual agents that generate facial expressions lack critical visual features such as expressive wrinkles, which could reduce their realistic appearance. Here, we examined the impact of dynamic facial texture on perceptions of realism of facial expressions of emotion and identified the emotion-specific features that enhance this perception. In a human perceptual judgment task, participants (20 white Westerners, 10 female) viewed pairs of facial expressions of the six classic emotions - happy, surprise, fear, disgust, anger and sad - with and without dynamic textures and selected the most realistic one from the pair. Analysis of participant choices showed that facial expressions with dynamic texture are perceived significantly more often as more realistic for all emotions except sad. Further analysis of the facial expression signals showed that emotion-specific features, such as darker forehead furrows in surprise, unilateral nose wrinkling in disgust, and shade variations around the cheeks in happy, enhanced perceptions of realism. Together, our results highlight the importance of equipping virtual agents with dynamic face movement texture to produce realistic facial expressions of emotion.