ABSTRACT
OBJECTIVE: Interpersonal problems have been identified as a plausible mechanism underlying the onset and maintenance of eating disorders. The Interpersonal Relationships in Eating Disorders (IR-ED) scale is the first eating disorders-specific measure of interpersonal problems, which was developed in a nonclinical sample. The aims of the current study were to (a) confirm the factor structure of the IR-ED within a large clinical sample, (b) investigate measurement invariance of the IR-ED across nonclinical and clinical samples, (c) examine the convergent validity of the IR-ED using a generic measure of interpersonal problems, and (d) investigate the incremental clinical utility of the IR-ED in uniquely predicting eating disorder symptomatology. METHOD: Treatment-seeking individuals (N = 437) completed the IR-ED at their initial assessment appointment at a specialist eating disorder outpatient service. RESULTS: A multiple-group confirmatory factor analysis supported an invariant bifactor structure comprising a general interpersonal problems factor and two group factors-Avoidance of Body Evaluation and Food-Related Interpersonal Tension. Convergent validity was demonstrated by a large, statistically significant correlation with a generic measure of interpersonal problems (r = 0.62, p < 0.001). A series of structural equation models further revealed unique incremental predictive utility of the IR-ED for eating disorder symptomatology. DISCUSSION: The IR-ED has strong psychometric properties and may prove beneficial in the assessment, formulation, and treatment of eating-specific interpersonal problems among patients with eating disorders.
ABSTRACT
Introduction: Body size judgements are frequently biased, or inaccurate, and these errors are further exaggerated for individuals with eating disorders. Within the eating disorder literature, it has been suggested that exaggerated errors in body size judgements are due to difficulties with integration. Across two experiments, we developed a novel integration task, named the Ebbinghaus Illusion for Bodies in Virtual Reality (VR), to assess whether nearby bodies influence the perceived size of a single body. VR was used to simulate the appearance of a small crowd around a central target body. Method and Results: In Experiment 1 (N = 412), participants were required to judge the size of a central female target within a crowd. Experiment 1 revealed an Ebbinghaus Illusion, in which a central female appeared larger when surrounded by small distractors, but comparatively smaller when surrounded by large distractors. In other words, the findings of Experiment 1 demonstrate that surrounding crowd information is integrated when judging an individual's body size; a novel measure of spatial integration (i.e., an Ebbinghaus Illusion for Bodies in VR). In Experiment 2 (N = 96), female participants were selected based on high (n = 43) and low (n = 53) eating disorder symptomatology. We examined whether the magnitude of this illusion would differ amongst those with elevated versus low eating disorder symptomatology, in accordance with weak central coherence theory, with the high symptomatology group displaying less spatial integration relative to the low group. The results of Experiment 2 similarly found an Ebbinghaus Illusion for Bodies in VR. However, illusion magnitude did not vary across high and low symptomatology groups. Discussion: Overall, these findings demonstrate that surrounding crowd information is integrated when judging individual body size; however, those with elevated eating disorder symptomatology did not show any integration deficit on this broader measure of spatial integration.
