From ears to waist: the influence of non-naturalistic sounds on body perception in relation to eating disorders symptomatology

Abstract Background People with clinical and subclinical eating disorders (EDs) show abnormalities in integrating multisensory bodily auditory information, which may contribute to the development and maintenance of body image disturbance. However, it remains unclear whether these impairments are specific to bodily auditory signals or extend to other auditory cues, and whether they differentially affect body parts depending on emotional salience. Methods Eighty-seven participants were recruited and allocated to either a subclinical ED group or a control group based on the Eating Disorder Examination Questionnaire (EDE-Q). We assessed the strength of two auditory-driven body illusions: a finger length illusion (Experiment 1) and a waist size illusion (Experiment 2). Illusion strength was measured using explicit measures (estimates of finger length and waist size) and self-report questionnaires. As a secondary aim, we examined individual differences in interoceptive awareness and sensory-processing sensitivity. Results Consistent with prior findings, sound had an overall effect on fingertip position and derived finger length estimates. However, the effect of sound on finger estimates did not differ significantly between groups. In contrast, the subclinical ED group did not show a waist-shrinking effect in response to sound, whereas the control group did. Discussion The task-specific pattern suggests that auditory-driven updating may be reduced for emotionally salient body regions in individuals with elevated ED symptomatology, although this interpretation should be confirmed in studies directly comparing body-part differences. The findings also suggest that attitudinal factors contribute to body image distortions alongside perceptual factors, particularly for emotionally salient body regions. Future studies should further validate the waist illusion as a tool to target body image disturbances and explore its potential as a complementary component in cognitive-behavioural interventions. Plain summary People with eating disorder (ED) symptoms may process body-related information differently, which can affect how they experience their body shape and size. In this study, we tested whether sounds can temporarily change how people perceive their body, and whether this depends on the body part. Eighty-seven participants were grouped as either having higher ED symptoms or being controls, based on a questionnaire. They took part in two sound-based body illusion experiments: one involving the perceived length of a finger and another involving perceived waist size. Everyone experienced the finger illusion in a similar way. However, in the waist experiment, sound-related differences were statistically detectable in the Control group but not in participants with higher ED symptoms. This task-specific pattern raises the possibility that sound-based changes in body perception may be reduced for an emotionally sensitive body region such as the waist. However, direct comparisons between body parts are needed to confirm this interpretation. These findings may help develop new ways to assess and potentially support early interventions for body image disturbance. Trial Registration https://link.springer.com/article/ https://doi.org/10.1186/s40337-023-00749-4