Role of Dynamic Facial Expressions in Judgement of Attractiveness: AI and Human Analysis

Facial attractiveness plays a crucial role in social interactions and mate selection, influencing judgments and behaviors in various contexts. While extensive research has examined structural facial features such as symmetry and averageness, the dynamic and modifiable nature of facial expressions remains underexplored. This study explores the influence of dynamic, modifiable facial expressions on perceived attractiveness through two experiments utilizing both human raters and artificial intelligence (AI) to analyze the relationship between facial expression positivity and attractiveness. In Experiment 1, we examined the effects of the experimenter’s control over the facial expressions on the facial expression and attractiveness ratings using two types of videos: one in which the stimulus models introduced themselves and another in which the subjects were controlled to be expressionless. Results revealed that the positivity and intensity of facial expressions, as assessed by facial expression analysis software, fluctuated based on the experimenter’s manipulation. Additionally, the variation in raters’ evaluations of facial expression positivity led to corresponding changes in attractiveness ratings. In Experiment 2, we investigated the relationship between facial expression ratings by humans and AI and their connection to attractiveness. The positivity of facial expressions in the video stimuli was analyzed by students and an AI-based facial expression analysis software, whereas a separate group of students rated the attractiveness of the same stimuli. Findings showed a positive correlation between the attractiveness ratings for both male and female stimuli and the positivity of facial expressions rated by both humans and AI. This indicates that attractive faces were perceived as having positive expressions and the actual positivity of the expressions themselves influenced attractiveness evaluations. These findings indicate that positivity in facial expressions plays a significant role in attractiveness perception. Future research should investigate how the relationship between attractiveness and expressions may be shaped by evolutionary pressures and social behaviors.