Role of facial familiarity and emotional expression intensity in ensemble emotion perception

Deep learning reveals what facial expressions mean to people in different cultures

Cross-cultural studies of the meaning of facial expressions have largely focused on judgments of small sets of stereotypical images by small numbers of people. Here, we used large-scale data collection and machine learning to map what facial expressions convey in six countries. Using a mimicry paradigm, 5,833 participants formed facial expressions found in 4,659 naturalistic images, resulting in 423,193 participant-generated facial expressions. In their own language, participants also rated each expression in terms of 48 emotions and mental states. A deep neural network tasked with predicting the culture-specific meanings people attributed to facial movements while ignoring physical appearance and context discovered 28 distinct dimensions of facial expression, with 21 dimensions showing strong evidence of universality and the remainder showing varying degrees of cultural specificity. These results capture the underlying dimensions of the meanings of facial expressions within and across cultures in unprecedented detail.

Perceiving the outlier in the crowd: The influence of facial identity

The accurate perception of groups with outliers can help us identify potential risks. However, it is unclear how outliers affect the perception of group emotion. To address this question, we conducted a study on group emotion perception in the context of facial identity. We presented 74 participants with pictures of crowds, and asked them to evaluate the valence ratios and intensity of the crowd by means of the Emotional Aperture Measure. The results revealed that outlier emotions were often overestimated within crowds. Moreover, we found that the emotional expression of a close friend modulated the perception of outliers. Specifically, when a close friend expressed the group emotion, participants overestimated the outlier less than when a close friend expressed the outlier emotion. These results suggest that people can detect outliers within groups, and that their perception of group emotion is influenced by close friends. Thus, we provide evidence that facial identity affects group emotion perception.