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Turnbull G, Lego S, Kennedy BL, Alexi J, Li YR, Engel MM, Mann G, Bayliss DM, Farrell S, Bell J. Sizing up the crowd: Assessing spatial integration difficulties in body size judgements across eating disorder symptomatology. Front Psychol 2023; 13:1003250. [PMID: 36687820 PMCID: PMC9853910 DOI: 10.3389/fpsyg.2022.1003250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 11/30/2022] [Indexed: 01/07/2023] Open
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.
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Affiliation(s)
- Georgia Turnbull
- School of Psychological Science, University of Western Australia, Crawley, WA, Australia,*Correspondence: Georgia Turnbull,
| | - Sophia Lego
- School of Psychological Science, University of Western Australia, Crawley, WA, Australia
| | - Briana L. Kennedy
- School of Psychological Science, University of Western Australia, Crawley, WA, Australia
| | - Joanna Alexi
- School of Psychological Science, University of Western Australia, Crawley, WA, Australia
| | - Yanqi R. Li
- School of Psychological Science, University of Western Australia, Crawley, WA, Australia
| | - Manja M. Engel
- Faculty of Social and Behavioural Sciences, Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands
| | - Georgina Mann
- School of Psychological Science, University of Western Australia, Crawley, WA, Australia
| | - Donna M. Bayliss
- School of Psychological Science, University of Western Australia, Crawley, WA, Australia
| | - Simon Farrell
- School of Psychological Science, University of Western Australia, Crawley, WA, Australia
| | - Jason Bell
- School of Psychological Science, University of Western Australia, Crawley, WA, Australia
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Turnbull G, Alexi J, Mann G, Li Y, Engel M, Bayliss DM, Farrell S, Bell J. EXPRESS: The Influence of Three-Dimensional Cues on Body Size Judgements. Q J Exp Psychol (Hove) 2022; 75:2318-2331. [PMID: 35034530 DOI: 10.1177/17470218221076850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Research has shown that body size judgements are frequently biased, or inaccurate. Critically, judgement biases are further exaggerated for individuals with eating disorders, a finding that has been attributed to difficulties integrating body features into a perceptual whole. However, current understanding of which body features are integrated when judging body size is lacking. In this study, we examine whether individuals integrate three-dimensional (3D) cues to body volume when making body size judgements. Computer-generated body stimuli were presented in a 3D Virtual Reality (VR) environment. Participants (N = 412) were randomly assigned to one of two conditions: in one condition the to-be-judged body was displayed binocularly (containing 3D cues to body volume), in the other, bodies were presented monocularly (2D cues only). Across 150 trials, participants were required to make a body size judgement of a target female body from a third-person point of view using an unmarked visual analogue scale (VAS). It was found that 3D cues significantly influenced body size judgements. Namely, thin 3D bodies were judged smaller, and overweight 3D bodies were judged larger, than their 2D counterpart. Furthermore, to reconcile these effects, we present evidence that the two perceptual biases, regression to the mean and serial dependence, were reduced by the additional 3D feature information. Our findings increase our understanding of how body size is perceptually encoded and creates testable predictions for clinical populations exhibiting integration difficulties.
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Affiliation(s)
- Georgia Turnbull
- School of Psychological Science, University of Western Australia (M304), 35 Stirling Highway, Crawley WA 6009, Australia 2720
| | - Joanna Alexi
- School of Psychological Science, University of Western Australia (M304), 35 Stirling Highway, Crawley WA 6009, Australia 2720
| | - Georgina Mann
- School of Psychological Science, University of Western Australia (M304), 35 Stirling Highway, Crawley WA 6009, Australia 2720
| | - Yanqi Li
- School of Psychological Science, University of Western Australia (M304), 35 Stirling Highway, Crawley WA 6009, Australia 2720
| | - Manja Engel
- Utrecht University, Faculty of Social and Behavioural Sciences, Experimental Psychology/Helmholtz Institute. Heidelberglaan 1, 3584 CS Utrecht, Netherlands 8125
| | - Donna M Bayliss
- School of Psychological Science, University of Western Australia (M304), 35 Stirling Highway, Crawley WA 6009, Australia 2720
| | - Simon Farrell
- School of Psychological Science, University of Western Australia (M304), 35 Stirling Highway, Crawley WA 6009, Australia 2720
| | - Jason Bell
- School of Psychological Science, University of Western Australia (M304), 35 Stirling Highway, Crawley WA 6009, Australia 2720
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