Automatic Facial Reactions to Emotional Body Expressions Are Not Driven by Emotional Experience

Perceiving emotional expressions automatically triggers a tendency to react with a matching facial expression. Although it is considered fundamental for healthy social interactions, the mechanism behind it is unclear. One prevalent explanation suggests that perceiving emotional expressions induces emotions in the observer and that it is these emotions that elicit the facial reactions. This study directly tested this hypothesis, investigating whether emotion elicitation is what drives the effect. Two experiments used a facial stimulus-response compatibility (SRC) paradigm-a widely used measure of the tendency to facially match emotional expressions-in which the irrelevant stimuli were happy and angry body postures. Reaction times were measured using facial electromyography. Experiment 1 replicated the known SRC effect to body postures using a simpler task with only one, prespecified, response. This established a novel variant of the paradigm in which the facial effects cannot be attributed to motor matching or response selection and which focuses specifically on the automatic components of the effect. Experiment 2 then added to this paradigm a habituation protocol and self-report ratings of affective valence. Results indicated that emotional body postures elicited limited emotional reactions, which were further habituated following repeated presentations. However, the facial SRC effect did not undergo such habituation, suggesting that reducing emotional reaction to observed expressions does not reduce the tendency to match those expressions. Our findings do not support the emotion elicitation hypothesis and suggest that automatic facial reactions to emotional body postures are not driven by emotional reactions to the stimuli.