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Provenzano L, Ciccarone S, Porciello G, Petrucci M, Cozzani B, Cotugno A, Bufalari I. Embodiment of underweight and normal-weight avatars affects bodily self-representations in anorexia nervosa. Heliyon 2024; 10:e32834. [PMID: 38988549 PMCID: PMC11233954 DOI: 10.1016/j.heliyon.2024.e32834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 06/05/2024] [Accepted: 06/10/2024] [Indexed: 07/12/2024] Open
Abstract
Body image distortion (BID) is a crucial aspect of anorexia nervosa (AN), leading to body overestimation, dissatisfaction, and low self-esteem. BID significantly influences the onset, maintenance, and relapse of the pathology. We assessed whether a Full Body Illusion (FBI) using under and normal-weight avatars' bodies affects perceptual body image and body schema estimations in both individuals with anorexia nervosa (AN) and healthy controls (HC). After each embodiment procedure, we asked participants to estimate the width of their hips (Perceptual Body Image Task) and the minimum aperture width of a virtual door necessary to pass through it (Body Schema Task). Additionally, we asked participants to rate the avatars in terms of self-similarity, attractiveness, and implicit disgust (i.e., pleasant/unpleasant body odour). Whereas participants with AN (N = 26) showed changes in body schema estimations after embodying the normal-weight avatar, no changes were found in HC (N = 25), highlighting increased bodily self-plasticity in AN. Notably, individuals with AN rated the normal weight avatar as the most similar to their real body, which was also considered the least attractive and the most repulsive. These ratings correlated with BID severity. Furthermore, at the explicit level, all participants reported feeling thinner than usual after embodying the underweight avatar. Overall, our findings suggest that BID in AN engages multiple sensory channels (from visual to olfactory) and components (from perceptual to affective), offering potential targets for innovative non-invasive treatments aimed at modifying flexible aspects of body representation.
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Affiliation(s)
| | - Sofia Ciccarone
- Dipartimento di Psicologia, Sapienza Università degli studi di Roma, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Giuseppina Porciello
- Dipartimento di Psicologia, Sapienza Università degli studi di Roma, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Manuel Petrucci
- Department of Human Sciences, Guglielmo Marconi University, Rome, Italy
| | - Barbara Cozzani
- Eating Disorders Unit, Department of Psychiatry, ASL Roma1, Rome, Italy
| | - Armando Cotugno
- Eating Disorders Unit, Department of Psychiatry, ASL Roma1, Rome, Italy
| | - Ilaria Bufalari
- Department of Developmental and Social Psychology, Sapienza Università degli studi di Roma, Rome, Italy
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Boucher JD, Bourgin J, Lassiaz J, Propice K, Metral M. The impact of weight and negative body image on the body schema in undergraduate women. Exp Brain Res 2024; 242:1373-1385. [PMID: 38565782 DOI: 10.1007/s00221-024-06827-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 03/19/2024] [Indexed: 04/04/2024]
Abstract
BACKGROUND AND OBJECTIVES Alterations of the sensory-motor body schema question the origins of such distortions. For example, in anorexia nervosa where patients think they are broader than they really are (body image) but act as if it was really the case (body schema). To date, the results of studies about what hinders the updating of the body schema so much (weight, body image) have been contradictory. METHODS We therefore conducted two studies that aimed to assess the impact of weight and body image problems on body schema in 92 young women without anorexia nervosa. For this purpose, we used a new body schema assessment tool (SKIN) that is sensitive enough to detect fine alterations of body schema in seven different body parts. RESULTS In Study 1, the thinness or overweight of the young women had a major impact on their tactile perception, especially because the assessed body part was a sensitive area for body dissatisfaction in young women (e.g., belly, thigh). In Study 2, the level of body dissatisfaction of the participants in its attitudinal and perceptual dimension also had a negative impact on their body schema, again in interaction with weight and body part. CONCLUSIONS These results imply that body dissatisfaction and thinness are predictors of massive body schema distortions. An oversized body schema could maintain various weight-control behaviors, thus risking the development, maintenance, or relapse of an eating disorder.
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Affiliation(s)
- Jean-David Boucher
- Univ. Savoie Mont Blanc, Univ. Grenoble Alpes, LIP/PC2S, 38000, Grenoble, France
| | - Jessica Bourgin
- Univ. Savoie Mont Blanc, Univ. Grenoble Alpes, LIP/PC2S, 38000, Grenoble, France
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France
| | | | - Klervi Propice
- Univ. Savoie Mont Blanc, Univ. Grenoble Alpes, LIP/PC2S, 38000, Grenoble, France
| | - Morgane Metral
- Univ. Savoie Mont Blanc, Univ. Grenoble Alpes, LIP/PC2S, 38000, Grenoble, France.
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Gadsby S, Zopf R, Brooks KR, Schumann A, de la Cruz F, Rieger K, Murr J, Wutzler U, Bär KJ. Testing visual self-misperception in anorexia nervosa using a symmetrical body size estimation paradigm. Int J Eat Disord 2023; 56:2149-2154. [PMID: 37578207 DOI: 10.1002/eat.24030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 07/11/2023] [Accepted: 07/11/2023] [Indexed: 08/15/2023]
Abstract
OBJECTIVE Individuals diagnosed with anorexia nervosa (AN) often report seeing themselves as overweight. While body size estimation tasks suggest that such individuals overestimate their body size, these tasks have failed to establish whether this misestimation stems from visual misperception. Misestimation might, instead, be due to response bias. We designed a paradigm to distinguish between visual and response bias contributions to body size misestimation: the symmetrical body size estimation (s-BSE) paradigm. METHOD The s-BSE paradigm involves two tasks. In the conventional task, participants estimate the width of their photographed body by adjusting the size of a rectangle to match. In the transposed task, participants adjust the size of a photograph of their body to match the rectangle. If overestimation stems exclusively from visual misperception, then errors in each task would be equal and opposite. Using this paradigm, we compared the performance of women diagnosed with AN (n = 14) against women without any eating disorder (n = 40). RESULTS In the conventional task, we replicated previous findings indicating that both women with AN and women without any eating disorder overestimate their body size. In the transposed task, neither group adjusted the bodies to be narrower than the rectangle. Participants with AN set their photographs to be significantly wider. DISCUSSION While we replicated previous findings of body size overestimation amongst women with AN and those without any eating disorder, our results are inconsistent with the hypothesis that such overestimation stems exclusively from visual misperception and instead suggest a substantial response bias effect. PUBLIC SIGNIFICANCE Women with anorexia nervosa overestimate their own body size. Research has not yet determined whether this overestimation stems from them seeing themselves as larger or other, non-visual factors. We employ a new method for distinguishing these possibilities and find that non-visual factors influence size estimates for women with and without anorexia nervosa. This method can help future research control for non-perceptual influences on participant responses.
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Affiliation(s)
- Stephen Gadsby
- Centre for Philosophical Psychology, Department of Philosophy, University of Antwerp, Antwerp, Belgium
| | - Regine Zopf
- Lab for Autonomic Neuroscience, Imaging and Cognition (LANIC), Department of Psychosomatic Medicine and Psychotherapy, Jena University Hospital, Jena, Germany
| | - Kevin R Brooks
- School of Psychological Sciences, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
- Lifespan Health & Wellbeing Research Centre, Macquarie University, Sydney, New South Wales, Australia
| | - Andy Schumann
- Lab for Autonomic Neuroscience, Imaging and Cognition (LANIC), Department of Psychosomatic Medicine and Psychotherapy, Jena University Hospital, Jena, Germany
| | - Feliberto de la Cruz
- Lab for Autonomic Neuroscience, Imaging and Cognition (LANIC), Department of Psychosomatic Medicine and Psychotherapy, Jena University Hospital, Jena, Germany
| | - Katrin Rieger
- Lab for Autonomic Neuroscience, Imaging and Cognition (LANIC), Department of Psychosomatic Medicine and Psychotherapy, Jena University Hospital, Jena, Germany
| | - Julia Murr
- Asklepios Fachklinikum Stadtroda, Clinic for Psychotherapy and Psychosomatic Medicine, Stadtroda, Germany
| | - Uwe Wutzler
- Asklepios Fachklinikum Stadtroda, Clinic for Psychotherapy and Psychosomatic Medicine, Stadtroda, Germany
| | - Karl-Jürgen Bär
- Lab for Autonomic Neuroscience, Imaging and Cognition (LANIC), Department of Psychosomatic Medicine and Psychotherapy, Jena University Hospital, Jena, Germany
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Longo MR, Medina S. Stimulus intensity modulates perceived tactile distance. Perception 2023; 52:774-781. [PMID: 37691587 DOI: 10.1177/03010066231200434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Several features of tactile stimuli modulate the perceived distance between touches. In particular, distances are perceived as farther apart when the time interval between them is longer, than when it is shorter. Such effects have been interpreted as a form of 'psychological relativity', analogous to Einstein's conception of a four-dimensional space-time. We investigated whether similar effects occur for stimulus features other than time, specifically stimulus intensity. We hypothesised that perceived distance would be increased when the two stimuli differed in intensity, since they would then be farther apart in a multi-dimensional feature space. Participants made verbal estimates of the perceived distance between two touches on their left hand. Intensity was manipulated such that both stimuli could be intense, both could be light, or one could be intense and the other light. We found no evidence for change in perceived tactile distance when stimuli intensity mis-matched. In contrast, there were clear effects of average stimulus intensity on perceived distance. Intense stimuli were judged as farther apart than light stimuli, and mixed stimuli were intermediate. These results are consistent with theories of general magnitude representation, which argue that multiple dimensions of magnitude are dependent on a shared underlying representation of domain-general magnitude.
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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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