Divergent Effects of the Enfacement Illusion on Face and Body Image Disturbance Across Female Eating Disorder Risk Groups

Embodiment illusion research suggests impaired multisensory integration in individuals with eating disorders (EDs), whilst offering potential therapeutic applications. However, face-related illusions remain unexplored. This study investigated the relationship between ED risk, susceptibility to the enfacement illusion, and improvements in face and body image disturbance after experiencing enfacement. Female Caucasian and Asian participants ( N = 226), categorised as high ED risk ( n = 102, 45.1%) or low ED risk ( n = 124, 54.9%), completed an online assessment featuring a novel enfacement illusion task involving synchronous and asynchronous facial mimicry. We assessed subjective (self-report) and objective (self-face recognition task) enfacement, alongside pre- and post-task self-reported face and body image disturbance. Multilevel modelling revealed successful enfacement induction across participants, with models explaining 3–11% unique variance in enfacement measures. While both groups showed similar illusion susceptibility, the effects of enfacement diverged significantly: high ED-risk participants experienced increased body and head dissatisfaction, whereas low ED-risk participants demonstrated reduced body dissatisfaction and dysmorphic concern (20-29% unique variance explained). These findings suggest a potential dissociation between face and body perception processes, whereby face-related multisensory integration processes may remain intact in ED populations, despite potentially adverse effects of enfacement on face and body image in high-ED-risk individuals.