Rethinking the bodily self: evidence from the enfacement illusion in women at risk for eating disorders

Bodily illusion research has demonstrated that altered bodily-self-perception in eating disorders (EDs) may be linked to abnormalities in the integration of sensory bodily signals. Experiencing bodily illusions can also temporarily reduce body image disturbance. Whether similar alterations in multisensory integration processes extend to self-face representation and whether face-based multisensory illusions can reduce face or body image disturbance remains unclear. This study investigated whether susceptibility to the enfacement illusion differs based on ED risk status and whether experiencing the illusion reduces face and body image disturbance.

The sample included 226 women classified as high (n = 102) or low (n = 124) ED risk, who underwent an enfacement illusion induction procedure involving synchronous (ilillusion-inducing) versus asynchronous (control) visuo-motor stimulation (via facial mimicry) between their own face and an unfamiliar person's face. Illusion strength was assessed subjectively (via self-report) and objectively (via a self-face recognition task), alongside pre- and post-illusion face and body image outcomes.

Synchronous interpersonal visuo-motor stimulation led to modest changes in self-face recognition (i.e., the other person's face came to be perceived as more similar to one's own); however, these changes were not modulated by ED risk status (high versus low). Cognitive-affective responses to the illusion diverged in unexpected ways. Low ED-risk participants reported reduced body dissatisfaction and dysmorphic concern following synchronous interpersonal visuo-motor stimulation, whilst high ED-risk participants reported increased head and body dissatisfaction following both synchronous and asynchronous stimulation.

These findings suggest that the multisensory processes underlying self-face representation, and ultimately supporting self-recognition and the integrity of self-other boundaries, may not be disrupted in individuals with elevated ED symptomatology. This observation may challenge the notion of a globally disrupted sense of bodily self in EDs, at least with respect to self-face processing. Instead, current results suggest that ED-related body image disturbance may reflect altered higher-order evaluative or affective processing of self-related social information rather than a fundamental deficit in multisensory integration.