Micro-expressions in Animated Agents

Abstract

The purpose of this research was to examine the perception of micro-expressions in animated agents with different visual styles. Specifically, the work reported in the paper sought to examine: (1) whether people can recognize micro-expressions in animated agents, (2) the extent to which the degree of exaggeration of micro-expressions affects recognition, perceived naturalness and intensity of the animated agents’ emotions, and (3) whether there are differences in recognition and perception based on the agent’s visual style (realistic vs stylized). The research work involved two experiments: a recognition study and an emotion rating study; 275 participants participated in each experiment. In the recognition study, the participants watched eight micro-expression animations representing four different emotions. Four animations featured a stylized character and four a realistic character. For each animation, subjects were asked to identify the character’s emotion conveyed by the mi-cro-expression. Results showed that all four emotions for both characters were recognized with an acceptable degree of accuracy. In the emotion rating study, participants watched two sets of eight animation clips. Eight animations in each set featured the characters performing both macro- and micro-expressions, the difference between these two sets was the exaggeration degree of micro-expressions (normal vs exaggerated). Participants were asked to recognize the character’s true emotion (conveyed by the micro-expressions) and rate the naturalness and intensity of the character’s emotion in each clip using a 5-point Likert scale. Findings showed that the degree of exaggeration of the micro-expressions had a significant effect on emotion’s naturalness rating, emotion’s intensity rating, and true emotion recognition, and the character visual style had a significant effect on emotion’s intensity rating.