The intensity of emotion: Altered motor simulation impairs processing of facial expressions in congenital facial palsy

Abstract

According to the models of sensorimotor simulation, we recognize others' emotions by subtly mimicking their expressions, which allows us to feel the corresponding emotion via facial feedback. In this contest, facial mimicry, which requires the implicit activation of the motor programs that produce a specific expression, is a crucial phenomenon occurring in emotion recognition, also concerning expression intensity. Consequently, difficulties to produce facial expressions would affect the experience of emotional understanding. In the present investigation, we recruited a sample (N = 11) of patients with Moebius syndrome (MBS), characterized by congenital facial paralysis, and a control group (N = 11) of healthy participants. By leveraging the MBS unique condition, we aimed at investigating the role of facial mimicry and sensorimotor simulation in creating a precise embodied concept of each emotion. The two groups underwent a sensitive facial emotion recognition task, optimally tuned to test sensitivity to emotion intensity and emotion discriminability in terms of their confusability with other emotions. Our study provides evidence of a deficit in recognizing emotions in MBS patients, expressed by a significant decrease in the rating of the intensity of three specific emotion categories, namely sadness, fear and disgust. Moreover, we observed an impairment in detecting these emotions, resulting in a stronger confusability of such emotions with the neutral and the secondary blended emotion. These findings provide support for embodied theories, which hypothesize that sensorimotor systems are involved in the detection and discrimination of emotions.