Professional actors demonstrate variability, not stereotypical expressions, when portraying emotional states in photographs

Tuan Le Mau,Emery N Brown,Jennifer M B Fugate,Katie Hoemann,Lisa Feldman Barrett,Sam H Lyons,Maria Gendron

doi:10.1038/s41467-021-25352-6

Abstract

It is long hypothesized that there is a reliable, specific mapping between certain emotional states and the facial movements that express those states. This hypothesis is often tested by asking untrained participants to pose the facial movements they believe they use to express emotions during generic scenarios. Here, we test this hypothesis using, as stimuli, photographs of facial configurations posed by professional actors in response to contextually-rich scenarios. The scenarios portrayed in the photographs were rated by a convenience sample of participants for the extent to which they evoked an instance of 13 emotion categories, and actors’ facial poses were coded for their specific movements. Both unsupervised and supervised machine learning find that in these photographs, the actors portrayed emotional states with variable facial configurations; instances of only three emotion categories (fear, happiness, and surprise) were portrayed with moderate reliability and specificity. The photographs were separately rated by another sample of participants for the extent to which they portrayed an instance of the 13 emotion categories; they were rated when presented alone and when presented with their associated scenarios, revealing that emotion inferences by participants also vary in a context-sensitive manner. Together, these findings suggest that facial movements and perceptions of emotion vary by situation and transcend stereotypes of emotional expressions. Future research may build on these findings by incorporating dynamic stimuli rather than photographs and studying a broader range of cultural contexts.

Highlights

It is long hypothesized that there is a reliable, specific mapping between certain emotional states and the facial movements that express those states
The scenarios in a given cluster were each associated with corresponding facial poses, and we computed intra-cluster match scores (m) for every pair of facial poses within each cluster as the number of activated action units (AUs) shared by the poses, over the total number of activated AUs across both[9], as in Eq 1: m
We examined in photographs how professional actors, who have functional expertise in conveying emotion, pose their faces to portray instances of anger, sadness, disgust, and other emotion categories across a variety of scenarios

Summary

Introduction

It is long hypothesized that there is a reliable, specific mapping between certain emotional states and the facial movements that express those states. In a typical study designed to test this hypothesis, untrained human participants are provided with a single impoverished scenario that is thought to be representative of a given emotion category (e.g., “You have been insulted, and you are very angry about it”9), and are asked to pose the facial configuration they believe they make to express that emotion[9,14,15] This approach limits the possibility of discovering expressive variation by encouraging participants to pose a stereotypical set of facial movements. The basic emotion view hypothesizes that not that all people scowl in anger on all occasions, but that people scowl when angry reliably and enough for one to infer that a person is angry when she is scowling

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Results

Conclusion