Experimental manipulation of visual attention affects body size adaptation but not body dissatisfaction

The effect of an odd-one-out visual search task on attentional bias, body size adaptation, and body dissatisfaction

Body image disturbance is a both a risk factor for, and a symptom of, many eating disorders and refers to the misperception of and dissatisfaction with one's own body. Women with high body dissatisfaction have been shown to direct more attention to low body mass index (BMI) bodies, which results in the overestimation of body size via body size adaptation. Therefore, attention may have a causal role in body image disturbance. We conducted a novel training visual search task with 142 young adult women who we trained to attend to either high or low BMI bodies. We assessed the effects of this training on attention to bodies of different sizes, body size adaptation, and body dissatisfaction. Women trained to attend to low BMI bodies decreased their perceptions of a 'normal' body size via adaptation from pre- to post-training (p < 0.001); however, women trained to attend to high BMI bodies showed no change in their perception of a 'normal' body size. We found no lasting effects of the training on attention to body size or body dissatisfaction; however, our visual search task showed poor internal consistency as a measure of attention. These findings indicate that attention to low BMI bodies may exacerbate body image disturbance in women. However, more reliable measures of attentional are required to confirm this finding.

Did you skip leg day? The neural mechanisms of muscle perception for body parts

While the neural mechanisms underpinning the perception of muscularity are poorly understood, recent progress has been made using the psychophysical technique of visual adaptation. Prolonged visual exposure to high (low) muscularity bodies causes subsequently viewed bodies to appear less (more) muscular, revealing a recalibration of the neural populations encoding muscularity. Here, we use visual adaptation to further elucidate the tuning properties of the neural processes underpinning muscle perception for the upper and lower halves of the body. Participants manipulated the apparent muscularity of upper and lower bodies until they appeared 'normal', prior to and following exposure to a series of top/bottom halves of bodies that were either high or low in muscularity. In Experiment 1, participants were adapted to isolated own-gender body halves from one of four conditions; increased (muscularity) upper (body half), increased lower, decreased upper, or decreased lower. Despite the presence of muscle aftereffects when the body halves the participants viewed and manipulated were congruent, there was only weak evidence of muscle aftereffect transfer between the upper and lower halves of the body. Aftereffects were significantly weaker when body halves were incongruent, implying minimal overlap in the neural mechanisms encoding muscularity for body half. Experiment 2 examined the generalisability of Experiment 1's findings in a more ecologically valid context using whole-body stimuli, producing a similar pattern of results as Experiment 1, but with no evidence of cross-adaptation. Taken together, the findings are most consistent with muscle-encoding neural populations that are body-half selective. As visual adaptation has been implicated in cases of body size and shape misperception, the present study furthers our current understanding of how these perceptual inaccuracies, particularly those involving muscularity, are developed, maintained, and may potentially be treated.

The relationship between body dissatisfaction and attentional bias to thin bodies in Malaysian Chinese and White Australian women: a dot probe study

Studies suggest that an attentional bias to thin bodies is common among those with high levels of body dissatisfaction, which is a risk factor for, and symptom of, various eating disorders. However, these studies have predominantly been conducted in Western countries with body stimuli involving images of White people. In a preregistered study, we recruited 150 Malaysian Chinese women and 150 White Australian women for a study using standardized images of East Asian and White Australian bodies. To measure attentional bias to thin bodies, participants completed a dot probe task which presented images of women who self-identified their ethnicity as East Asian or as White Australian. Contrary to previous findings, we found no evidence for an association between body dissatisfaction and attentional bias to thin bodies. This lack of association was not affected by participant ethnicity (Malaysian Chinese versus White Australian) or ethnic congruency between participants and body stimuli (own-ethnicity versus other-ethnicity). However, the internal consistency of the dot probe task was poor. These results suggest that either the relationship between body dissatisfaction and attentional bias to thin bodies is not robust, or the dot probe task may not be a reliable measure of attentional bias to body size.

Mirror exposure following visual body-size adaptation does not affect own body image

Prolonged visual exposure to large bodies produces a thinning aftereffect on subsequently seen bodies, and vice versa. This visual adaptation effect could contribute to the link between media exposure and body shape misperception. Indeed, people exposed to thin bodies in the media, who experience fattening aftereffects, may internalize the distorted image of their body they see in the mirror. This preregistered study tested this internalization hypothesis by exposing 196 young women to an obese adaptor before showing them their reflection in the mirror, or to a control condition. Then, we used a psychophysical task to measure the effects of this procedure on perceptual judgements about their own body size, relative to another body and to the control mirror exposure condition. We found moderate evidence against the hypothesized self-specific effects of mirror exposure on perceptual judgements. Our work strengthens the idea that body size adaptation affects the perception of test stimuli rather than the participants' own body image. We discuss recent studies which may provide an alternative framework to study media-related distortions of perceptual body image.

Perception of the non-dominant hand as larger after non-judgmental focus on its details

We investigated whether brief non-judgmental focus on the details of one's non-dominant hand might lead to changes in perception of its size, and if such a change would be related to central coherence, body dissatisfaction, or how much participants liked their hand. After two pilot experiments (N = 28 and N = 30 respectively: Appendix 1), a within-subject experiment (N = 82) was conducted. Subjects were mainly university students. They were asked to rate the size of their non-dominant hand and how much they liked it, and the size of an external object (a X-box controller) on a visual-analog scale before and after focusing on their details for 5 min, as well as the size of another object (a calculator) before and after a 5 min long distraction task. After completing the tasks, they were asked to respond to a brief questionnaire on body dissatisfaction. A s significant interaction between time and factors (non-dominant hand, X-box controller and calculator) emerged (F(2, 78) = 6.41, p = .003). Participants rated their hand as larger after focusing on its details compared to baseline, and this change was significantly larger than those reported for the X-box controller. No significant change in how they liked their hand was observed, and contrary to the pilot experiments, the perceived change in size of the hand was not related to body dissatisfaction. The significant change in reporting of the size of the hand after focusing on its details seems to be an interesting finding, worth further replications.

A Retrospective Literature Review of Eating Disorder Research (1990–2021): Application of Bibliometrics and Topical Trends

Despite the growing importance of eating disorders in society and academic literature, only a few bibliometric review studies using bibliometric analysis were available. Hence, this study aimed to explore and uncover hidden research topics and patterns in articles in terms of eating disorders over the last 30 years. In total, 4111 articles on eating disorders were analyzed using bibliometrics, network analyses, and structural topic modeling as the basis of mixed methods. In addition to general statistics about the journal, several key research topics, such as eating disorder (ED) treatment, ED symptoms, factors triggering ED, family related factors, eating behaviors, and social factors, were found based on topic correlations. This study found the key research variables that are frequently studied with EDs, such as AN, BN, BED, and ARFID. This study may help clinicians comprehend important risk factors associated with EDs. Moreover, the findings about key ED research topics and their association can be helpful for future studies to construct a comprehensive ED research framework. To our knowledge, this is the first study to use topic modeling in an academic journal on EDs and examine the diversity in ED research over 30 years of published research.

Changes in the perceived size of the body following exposure to distorted self-body images

Inaccurate perceptions, such as under- or over-estimation of body size are often found in clinical eating disorder populations but have recently been shown also in healthy people. However, it is not yet clear how body size perception may be affected when the internal body representation is manipulated. In this study, visual adaptation was used to investigate whether exposure to distorted visual feedback alters the representation of body size and how long any such effects might last. Participants were exposed for five minutes to a distorted life-size image of themselves that was either 20% wider or 20% narrower than their normal size. Accuracy was measured using our novel psychophysical method that taps into the implicit body representation. The accuracy of the representation was assessed at 6, 12 and 18 min following exposure to adaptation. Altered visual feedback caused changes in participants' judgements of their body size: adapting to a wider body resulted in size overestimation whereas underestimations occurred after adapting to a narrower body. These distortions lasted throughout testing and did not fully return back to normal within 18 min. The results are discussed in terms of the emerging literature indicating that the internal representation of the body is dynamic and flexible.

Psychometric investigation of the Attention to Body Shape Scale in Brazilian adults

The objectives of the study were to develop a Portuguese version of Attention to Body Shape Scale (ABS), estimate the psychometric properties of the ABS for Brazilian data, and compare the ABS scores between the sexes and the different sample characteristics. The Portuguese version was developed following a standardized protocol. The factorial and convergent validity were evaluated using goodness-of-fit parameters and average variance extracted. Composite reliability and ordinal coefficient alpha were calculated. The invariance of the fitted model was investigated across independent subsamples using multigroup analysis. The scores were compared between variables using two-way ANOVA. A total of 1,056 individuals (71% female) with a mean age of 26.1 (SD=6.4) years participated in the study. Item 3 was removed due to low factor loading. The refined model presented good psychometric properties for the data. Different characteristics contributed to greater attention to body shape. The Portuguese version of the ABS will be useful to investigate attention to body shape in Brazil. The validity and reliability of the data supported the adequacy of the refined model. Specific characteristics influenced attention to body shape, and therefore, should be considered in future protocols.

The effect of attention on body size adaptation and body dissatisfaction

Attentional bias to low-fat bodies is thought to be associated with body dissatisfaction-a symptom and risk factor of eating disorders. However, the causal nature of this relationship is unclear. In three preregistered experiments, we trained 370 women to attend towards either high- or low-fat body stimuli using an attention training dot probe task. For each experiment, we analysed the effect of the attention training on (i) attention to subsequently presented high- versus low-fat body stimuli, (ii) visual adaptation to body size, and (iii) body dissatisfaction. The attention training had no effect on attention towards high- or low-fat bodies in an online setting (Experiment 1), but did increase attention to high-fat bodies in a laboratory setting (Experiment 2). Neither perceptions of a 'normal' body size nor levels of body dissatisfaction changed as a result of the attention training in either setting. The results in the online setting did not change when we reduced the stimulus onset-asynchrony of the dot probe task from 500 to 100 ms (Experiment 3). Our results provide no evidence that the dot probe training task used here has robust effects on attention to body size, body image disturbance or body dissatisfaction.

Self-Perception and Self-Acceptance Are Related to Unhealthy Weight Control Behaviors in Catalan Adolescents: A Cross-Sectional Study

Adolescence is associated with a higher vulnerability that may result in a high dissatisfaction, the practice of unhealthy weight-control behaviors (UWCB) and, eventually, the onset of body image-related mental disorders. These factors are strongly associated with the social context, so it is important to characterize them in local or regional studies. To assess the relationship between body image and UWCB presence, a cross-sectional study was performed among 2496 schooled adolescents from Lleida (Spain) between 2017 and 2019. Their perceived and desired images were evaluated and compared with the real image in order to obtain the body distortion and the body dissatisfaction and relate them with UWCB. The studied individuals perceived themselves thinner than they actually were, with no differences between males and females. However, differences were found regarding body dissatisfaction, showing that females desired to be thinner, while males desired a more corpulent body image. Furthermore, one out of ten individuals reported UWCB, with higher prevalence among females. UWCB was associated with a desire to be thinner and with distorted body images. It is essential to work on self-perception and self-acceptance in early adolescence from an interdisciplinary perspective at educational, social and health levels to promote health in adolescence.

Implicit mechanisms of body image alterations: The covert attention exposure effect

Visual exposure to extreme-sized bodies elicits explicit self-body image variations. Several features of such modulation remain to be clarified. In this study we explored whether this effect: (i) acts on implicit mechanisms in modifying one's body-size perception, (ii) is body-exposure-specific also at the implicit level, and (iii) is modulated by interoceptive sensibility. We assigned a covert attention task to 100 women, exposing them to extreme-sized bodies (thin and fat) or extreme-sized objects (thin and fat bottles). Before and after the attentional exposure, we tested the association between the "self/others" and "thin/fat" concepts using an Implicit Association Test. We also collected a measure of interoceptive sensibility by means of a self-report questionnaire. Results showed that participants exposed to fat bodies implicitly presented a stronger association between the "self" and "thin" concepts. This association was significantly weaker in the group exposed to thin bodies. This effect was absent after exposure to thin and fat bottles. Notably, participants with a higher tolerance of negative bodily interoceptive signals were less susceptible to the malleability of body image exerted by the exposure attentional task. Our findings shed new light on the relationship between the perception of internal (e.g., visceral) and external (e.g., visual) signals in the representation of our body.

Does repeatedly viewing overweight versus underweight images change perception of and satisfaction with own body size?

Body dissatisfaction is associated with subsequent eating disorders and weight gain. One-off exposure to bodies of different sizes changes perception of others' bodies, and perception of and satisfaction with own body size. The effect of repeated exposure to bodies of different sizes has not been assessed. We randomized women into three groups, and they spent 5 min twice a day for a week completing a one-back task using images of women modified to appear either under, over, or neither over- nor underweight. We tested the effects on their perception of their own and others' body size, and satisfaction with own size. Measures at follow-up were compared between groups, adjusted for baseline measurements. In 93 women aged 18-30 years, images of other women were perceived as larger following exposure to underweight women (and vice versa) (p < 0.001). There was no evidence for a difference in our primary outcome measure (visual analogue scale own size) or in satisfaction with own size. Avatar-constructed ideal (p = 0.03) and avatar-constructed perceived own body size (p = 0.007) both decreased following exposure to underweight women, possibly due to adaptation affecting how the avatar was perceived. Repeated exposure to different sized bodies changes perception of the size of others' bodies, but we did not find evidence that it changes perceived own size.

Muscle and fat aftereffects and the role of gender: Implications for body image disturbance

Body image disturbance - a cause of distress amongst the general population and those diagnosed with various disorders - is often attributed to the media's unrealistic depiction of ideal bodies. These ideals are strongly gendered, leading to pronounced fat concern amongst females, and a male preoccupation with muscularity. Recent research suggests that visual aftereffects may be fundamental to the misperception of body fat and muscle mass - the perceptual component of body image disturbance. This study sought to establish the influence of gender on these body aftereffects. Male and female observers were randomly assigned to one of four adaptation conditions (low-fat, high-fat, low-muscle, and high-muscle bodies) and were asked to adjust the apparent fat and muscle levels of male and female bodies to make them appear as 'normal' as possible both before adaptation and after adaptation. While neither the gender of observers nor of body stimuli had a direct effect, aftereffect magnitude was significantly larger when observers viewed own-gender (compared with other-gender) stimuli. This effect, which may be due to attentional factors, could have implications for the development of body image disturbance, given the preponderance of idealized own-gender bodies in media marketed to male and female consumers.

Are attitudinal and perceptual body image the same or different? Evidence from high-level adaptation

We used a high-level adaptation paradigm to distinguish between two hypotheses: (1) perceptual and attitudinal body image measurements reflect conceptually different mechanisms which are statistically independent of each other; (2) attitudinal (e.g., questionnaire) and perceptual (e.g., visual yes-no) body image tasks represent two different ways of measuring exactly the same construct. Forty women, with no history of eating disorders, carried out the experiment. Each participant carried out five adaptation blocks, with adapting stimuli representing female bodies at: extreme-low body mass index (BMI), mid-low BMI, actual BMI of the observer, mid-high BMI, and extreme-high BMI. Block order was randomized across participants. The main outcome variable was percentage error in participants' self-estimates of body size, measured post-adaption. In regressions of this percentage error on the strength of the adapting stimuli together with observers' attitudinal body image as a covariate, we found positive regression slopes and no evidence for any interaction between the fixed effects. Therefore, we conclude that perceptual and attitudinal body image mechanisms are indeed independent of each other. In the light of this evidence, we discuss how people with eating disorders, like anorexia nervosa, may come to over-estimate their body size.

Looking at the Figures: Visual Adaptation as a Mechanism for Body-Size and -Shape Misperception

Many individuals experience body-size and -shape misperception (BSSM). Body-size overestimation is associated with body dissatisfaction, anxiety, depression, and the development of eating disorders in individuals who desire to be thinner. Similar symptoms have been noted for those who underestimate their muscularity. Conversely, individuals with high body mass indices (BMI) who underestimate their adiposity may not recognize the risks of or seek help for obesity-related medical issues. Although social scientists have examined whether media representations of idealized bodies contribute to the overestimation of fat or underestimation of muscle, other scientists suggest that increases in the prevalence of obesity could explain body-fat underestimation as a form of renormalization. However, these disparate approaches have not advanced our understanding of the perceptual underpinnings of BSSM. Recently, a new unifying account of BSSM has emerged that is based on the long-established phenomenon of visual adaptation, employing psychophysical measurements of perceived size and shape following exposure to "extreme" body stimuli. By inducing BSSM in the laboratory as an aftereffect, this technique is rapidly advancing our understanding of the underlying mental representation of human bodies. This nascent approach provides insight into real-world BSSM and may inform the development of therapeutic and public-health interventions designed to address such perceptual errors.

Editorial to the virtual issue highlighting neuroscience based research in eating disorders to mark the 49th Society for Neuroscience Annual Meeting

OBJECTIVE

This virtual issue of the International Journal of Eating Disorders highlights recently published research that is based on neuroscience concepts, to mark the 49th Society for Neuroscience Annual Meeting in Chicago, IL, in November 2019.

METHODS AND RESULTS

The collection of articles includes research published between 2018 and 2019 that fall within the broader field of clinical neuroscience. Those articles span a broad range of themes, including food intake regulation and reward circuitry, taste perception, decision-making, cognitive and emotional bias, and targeting altered brain circuits using novel therapeutic methods.

DISCUSSION

The eating disorders field as a whole is increasingly incorporating neuroscience-based concepts when studying those disorders and developing disease models. We hope that this virtual issue will further stimulate discussion and research that is focused on brain circuits and neurobiology to study etiology and pathophysiology of eating disorders to develop more effective treatments.