Culturally diverse facial expression signals diminish the precision of emotion communication across cultures

Abstract Communicating emotional intensity provides rich information both about the nature and likelihood of helpful or harmful behaviors. How human facial expressions achieve this complex signalling task remains unknown. Here, using the six classic emotions—happy, surprise, fear, disgust, anger, sad—in two distinct cultures (East Asian, Western European; total N = 120 individual observers), we mathematically modelled the specific facial movements that signal emotion categories and emotion intensity. In both cultures, specific facial movements cascade emotion category and intensity information over time via a distinct temporal structure. Cross-cultural analysis revealed systematic cultural variance in these facial signals that diminishes cross-culture communication but preserves communication of priority threat-related information. Together, our results provide new insights into how facial expressions can achieve complex signalling tasks via compositional and dynamic structures.