Beyond Faces: the Relevance of Moebius Syndrome to Emotion Recognition and Empathy

Embodied simulation theories propose that recognizing the emotions of other individuals relies on mimicry of perceived behaviour in parallel with internal simulation of that behaviour. An application of this view, reverse simulation, predicts that the inability to make facial expressions impairs recognition of emotional faces. However, behavioural studies of adults with Moebius Syndrome (MS), a congenital condition of bilateral facial palsy and impaired lateral eye movement, show that such individuals recognize emotional facial expressions. Hence, facial feedback does not causally inform recognition of emotional faces. A limitation of such behavioural studies is that they only show that individuals with MS can perform emotion recognition under favorable presentation conditions. The participants passively observed facial stimuli in recognition tasks presenting simple and common emotional faces. It is conceivable that facial mimicry may play a causal role in recognition tasks that are either complex or novel. While MS cannot realise this possibility, qualitative studies of MS individuals do support process-theories of embodiment and the contributions of non-facial simulations to emotion recognition and empathy. These studies report that MS individuals embody self and other emotional expressions in non-facial motor activity during complex and novel interactions with others, and that MS individuals use such simulations as signals to enable extended interactions with others. These findings are consistent with evidence showing that bodily embodiment is often required in emotion recognition and empathy.