title: Independent Aftereffects of Fat and Muscle: Implications for neural encoding, body space representation, and body image disturbance.
abstract: Although research addressing body size misperception has focused on socio-cognitive processes, such as internalization of the "ideal" images of bodies in the media, the perceptual basis of this phenomenon remains largely unknown. Further, most studies focus on body size per se even though this depends on both fat and muscle mass - variables that have very different relationships with health. We tested visual adaptation as a mechanism for inducing body fat and muscle mass misperception, and assessed whether these two dimensions of body space are processed independently. Observers manipulated the apparent fat and muscle mass of bodies to make them appear "normal" before and after inspecting images from one of four adaptation conditions (increased fat/decreased fat/increased muscle/decreased muscle). Exposure resulted in a shift in the point of subjective normality in the direction of the adapting images along the relevant (fat or muscle) axis, suggesting that the neural mechanisms involved in body fat and muscle perception are independent. This supports the viability of adaptation as a model of real-world body size misperception, and extends its applicability to clinical manifestations of body image disturbance that entail not only preoccupation with thinness (e.g., anorexia nervosa) but also with muscularity (e.g., muscle dysmorphia).
authors.affiliation: Department of Psychology, Macquarie University, Sydney, Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sturman
authors.affiliation: Department of Psychology, Macquarie University, Sydney, Australia.|ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, Australia.|Perception in Action Research Centre (PARC), Faculty of Human Sciences, Macquarie University, Sydney, Australia.
authors.forename: Ian D
authors.initials: ID
authors.lastname: Stephen
authors.affiliation: Centre for Health Research, School of Medicine, Western Sydney University, Sydney Australia.|Centre for Rural Health, University of Tasmania, Launceston Tasmania.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Mond
authors.affiliation: Department of Psychology, Macquarie University, Sydney, Australia.|Perception in Action Research Centre (PARC), Faculty of Human Sciences, Macquarie University, Sydney, Australia.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Stevenson
authors.affiliation: Department of Psychology, Macquarie University, Sydney, Australia.|Perception in Action Research Centre (PARC), Faculty of Human Sciences, Macquarie University, Sydney, Australia.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Brooks
mesh_terms: D000328:Adult; D000856:Anorexia Nervosa / Q000473:pathology / Q000523:psychology; D001828:Body Image / Q000523:psychology*; D049628:Body Size / Q000502:physiology*; D005260:Female; D018594:Human Body; D006801:Humans; D008297:Male; D008402:Mass Media; D009132:Muscles / Q000502:physiology*; D013851:Thinness / Q000523:psychology