Mirror feedback and judgments of 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.

Factorial Model of Obese Adolescents: The Role of Body Image Concerns and Selective Depersonalization-A Pilot Study

BACKGROUND

The relationship binding body weight to psychological well-being is unclear. The present study aims at identifying the contribution, and specificity, of some dimensions (i.e., eating-related symptoms, body image disorders, eating habits, personality traits, and emotional difficulties) characterizing the psychological profile of obese adolescents (749 participants, 325 females; 58.3% normal-weight, 29.9% overweight, and 11.7% obese; mean age = 16.05, SD = 0.82).

METHODS

By introducing the scores obtained by standardized self-report tools into a generalized linear model, a factorial reduction design was used to detect the best fitting discriminant functions and the principal components explaining the higher proportion of the variance.

RESULTS

We found two discriminant functions correctly classifying 87.1% of normal-weight, 57.2% of overweight, and 68.2% of obese adolescents. Furthermore, two independent factors, explaining 69.68% of the total variance, emerged.

CONCLUSIONS

The first factor, "Body Image Concerns", included the drive for thinness, body dissatisfaction, and interpersonal distrust. The second factor, "Selective Depersonalization", included a trend toward depersonalization and dissatisfaction with the torso. The neurophysiological implications of our findings will be discussed.

Higher general executive functions predicts lower body mass index by mitigating avoidance behaviors

BACKGROUND

The present study examines the relationship between obesity, executive functions, and body image in a nonclinical population from southern Italy.

METHODS

General executive functioning (Frontal Assessment Battery-15), and body image disturbances (Body Uneasiness Test) were assessed in a sample including 255 participants (138 females, M age = 43.51 years, SD = 17.94, range = 18-86 years; M body mass index (BMI) = 26.21, SD = 4.32, range = 18.03-38.79).

FINDINGS

Multiple Linear Regression Analysis indicated that age, years of education, FAB15 score, body image concerns, and avoidance predicted the variance of BMI. A subsequent mediation analysis highlighted that the indirect effect of FAB15 on BMI through avoidance was statistically significant.

INTERPRETATION

Our results suggest that more performing executive functioning predicts a decrease in BMI that is partially due to the mitigation of avoidance behaviors.

Body size estimation in obesity: a systematic review and meta-analysis

Previous research about body size estimation in obesity reported heterogeneous results. This might be related to the fact that the tasks adopted explored different body representations. Classifying the previous studies according to the specific body representation probed (i.e. implicit, explicit or both) might clarify discordant findings. A systematic review and meta-analysis of research articles assessing body size estimation in individuals affected by obesity compared with healthy weight individuals were performed in PubMed and Web of Science. Additional records were identified by reference lists inspection. The last search was run in May 2021. Two independent authors performed data extraction according to predefined criteria. Both groups either overestimated or underestimated the implicit body representation depending on the task used and the body part considered. Conversely, the explicit representation of the body was mainly overestimated by both individuals with obesity and healthy weight. In tasks relying on both these representations, overestimation and underestimation were reported in both groups, possibly depending on the degree of which each procedure relied on the explicit and/or implicit representation of the body. According to the meta-analysis, individuals with obesity tended to be significantly less accurate in body size estimations than participants with healthy weight. We confirmed that heterogeneous findings in body size estimation in obesity are related to the adoption of different tasks, which likely involve different body representations. We discussed the role of body dissatisfaction and altered somatosensation in the lower accuracy observed in obesity.

The Virtual Hand Illusion in Obesity: Dissociation Between Multisensory Interactions Supporting Illusory Experience and Self-Location Recalibration

The Rubber Hand Illusion (RHI) is used widely to investigate the multisensory integration mechanisms that support bodily self-consciousness and, more specifically, body ownership and self-location. It has been reported that individuals affected by obesity show anomalous multisensory integration processes. We propose that these obesity-induced changes could lead to an unusual susceptibility to the RHI and anomalous bodily self-experience. To test this hypothesis, we administered a modified version of the RHI (using a picture of the participant's hand) to individuals affected by obesity and participants with a healthy weight. During synchronous and asynchronous stimulation, we compared the subjective experience of the illusion (using a questionnaire) and the effect of the illusion on self-location (i.e., proprioceptive drift). In accordance with the illusion phenomenology, both groups had a comparable subjective illusory experience after the synchronous stimulation. Nevertheless, individuals affected by obesity showed less recalibration of self-location than healthy weight participants. In light of a recent interpretation of the multisensory integration mechanisms that underpin the RHI, our findings suggest that in obesity visuo-tactile integration supporting the subjective experience of the illusion is preserved, whereas visuo-proprioceptive integration for self-location is reduced.

Women With Obesity Are Not as Curvy as They Think: Consequences on Their Everyday Life Behavior

Two studies explore the impact of body size on daily life activities of women with obesity. In the first study, ethnographic techniques (first-person perspective video recordings) and subsequent interviews based on the video recordings were used. Results showed atypical behavior of women with obesity and ex-obese women related to memories of embarrassing experiences regarding personal body size (sitting, passing doors sideways, over-careful navigation in public space, and choosing clothes sizes too large.) Women with obesity seem to behave as if they thought they had a larger body than it actually was. These atypical behaviors are related to memories of embarrassing experiences regarding personal body size and stigma. Overweight women exhibit the same behavior but to a lesser and less systematic degree. In the second study, the represented (imagined) body size was compared to the perceived (in a mirror) body size with digital morphing techniques. In the mirror condition, the perceived image is accurate, while in the absence of a mirror women with obesity overestimate their body size by about 30%. Moreover, overestimation of imagined body size increased according to the weight status. Finally, women who had bariatric surgery had poorer estimates than women who had not. This would result of being continuously reminded of obesity and its stigma by daily embarrassing experiences, by being confronted with an environment designed for normal weight (e.g., narrow seats, turnstiles etc.) that makes obesity salient. We suggest that body size overestimation is a case of accentuation where things that matter are perceived bigger. These results could also been explained by the allocentric lock theory.

Weight-Related Selves and Their Relationship With Body Mass Index Among Young Individuals in Curaçao

Based on the assumptions of self-discrepancy theory, the present study examined the degree of overweight, weight-related body images, and the relation between these images and body mass index (BMI) among two samples of young people from Curaçao (secondary school students, n = 176; undergraduate students, n = 205). In addition to BMI, participants reported their current, ideal, and most feared body sizes, the thinnest and largest body sizes still acceptable to them, and the body size they considered the healthiest by means of the Contour Drawing Rating Scale. We expected females to show a larger discrepancy between current and ideal body size than males (Hypothesis 1) and that this discrepancy (as an indicator of body dissatisfaction) would be related more strongly to BMI among females than among males (Hypothesis 2). Results yielded support for Hypothesis 1 among secondary school students only. Only in the undergraduate sample, BMI and body dissatisfaction were related, but equally so for males and females. Possible explanations are discussed as well as implications for weight management interventions.

The Role of Visual Information in Body Size Estimation

The conscious representation of our physical appearance is important for many aspects of everyday life. Here, we asked whether different visual experiences of our bodies influence body width estimates. In Experiment 1, width estimates of three body parts (foot, hips, and shoulders) without any visual access were compared to estimates with visual feedback available in a mirror or from a first-person perspective. In the no visual access and mirror condition, participants additionally estimated their head width. There was no influence of viewing condition on body part width estimates. Consistent with previous research, all body part widths were overestimated with greater overestimation of hip and head width. In Experiment 2, participants estimated the size of unfamiliar noncorporeal objects to test whether this overestimation was partially due to the metric body size estimation method or our experimental conditions. Object width was overestimated with visual feedback in a mirror available as compared to when directly looking at the object, but only for objects placed at shoulder and head height. We conclude that at least some of the overestimation of body part width seems to be body specific and occurs regardless of the visual information provided about the own body.

Body-scaled action in obesity during locomotion: Insights on the nature and extent of body representation disturbances

OBJECTIVE

Conscious perception of our own body, also known as body image, can influence body-scaled actions. Certain conditions such as obesity are frequently accompanied by a negative body image, leaving open the question if body-scaled actions are distorted in these individuals.

METHODS

To shed light on this issue, we asked individuals affected by obesity to process dimensions of their own body in a real action: they walked in a straight-ahead direction, while avoiding collision with obstacles represented by door-like openings that varied in width.

RESULTS

Participants affected by obesity showed a body rotation behavior similar to that of the healthy weighted, but differences emerged in parameters such as step length and velocity.

CONCLUSION

When participants with obesity walk through door-like openings, their body parts rotation is scaled according to their physical body dimensions; however, they might try to minimize risk of collision. Our study is in line with the hypothesis that unconscious body-scaled actions are related to emotional, cognitive and perceptual components of a negative body image.

Errors in Judging Information about Reflections in Mirrors

We investigated people's perception and knowledge of planar mirror reflections. People were accurate at deciding when they could first see their reflection as they approached a mirror from the side, but only if their reflection was visible. Most people stopped too early if the mirror was covered up. People also overestimated the size of the reflection of their face on the surface of a mirror if they were shown a covered mirror. Their accuracy improved somewhat if their reflection was visible but, unlike the first task, they still made striking errors. Perceptual feedback thus improved performance at predicting the behaviour of mirror reflections in both tasks but failed to eliminate errors in the second task. The overestimation of reflection size was not face-specific as it generalised to novel stimuli (paper ellipses) and it was found with both a matching response and for verbal size estimations. The early error in the first task appears to be due to an inaccurate belief that can be overridden by perceptual feedback. The overestimation in the second task is primarily caused by a powerful size-constancy effect.

External self-representations improve self-awareness in a child with autism

We have previously suggested that the social symptoms of autism spectrum disorder (ASD) could be caused in part by a dysfunctional mirror neuron system (MNS). Since the recursive activity of a functioning MNS might enable the brain to integrate visual and motor sensations into a coherent body schema, the deficits in self-awareness often seen in ASD might be caused by the same mirror neuron dysfunction. CL is an autistic adolescent who is profoundly fascinated with his reflection, looking in mirrors at every opportunity. We demonstrate that CL's abnormal gait improves significantly when using a mirror for visual feedback. We also show that both the fascination and the happiness that CL derives from looking at a computer-generated reflection diminish when a delay is introduced between the camera input and screen output. We believe that immediate, real-time visual feedback allows CL to integrate motor sensations with external visual ones into a coherent body schema that he cannot internally generate, perhaps due to a dysfunctional MNS.

Tactile mental body parts representation in obesity

Obese people׳s distortions in visually-based mental body-parts representations have been reported in previous studies, but other sensory modalities have largely been neglected. In the present study, we investigated possible differences in tactilely-based body-parts representation between an obese and a healthy-weight group; additionally we explore the possible relationship between the tactile- and the visually-based body representation. Participants were asked to estimate the distance between two tactile stimuli that were simultaneously administered on the arm or on the abdomen, in the absence of visual input. The visually-based body-parts representation was investigated by a visual imagery method in which subjects were instructed to compare the horizontal extension of body part pairs. According to the results, the obese participants overestimated the size of the tactilely-perceived distances more than the healthy-weight group when the arm, and not the abdomen, was stimulated. Moreover, they reported a lower level of accuracy than did the healthy-weight group when estimating horizontal distances relative to their bodies, confirming an inappropriate visually-based mental body representation. Our results imply that body representation disturbance in obese people is not limited to the visual mental domain, but it spreads to the tactilely perceived distances. The inaccuracy was not a generalized tendency but was body-part related.

Weight status and the perception of body image in men

Understanding the role of body size in relation to the accuracy of body image perception in men is an important topic because of the implications for avoiding and treating obesity, and it may serve as a potential diagnostic criterion for eating disorders. The early research on this topic produced mixed findings. About one-half of the early studies showed that obese men overestimated their body size, with the remaining half providing accurate estimates. Later, improvements in research technology and methodology provided a clearer indication of the role of weight status in body image perception. Research in our laboratory has also produced diverse findings, including that obese subjects sometimes overestimate their body size. However, when examining our findings across several studies, obese subjects had about the same level of accuracy in estimating their body size as normal-weight subjects. Studies in our laboratory also permitted the separation of sensory and nonsensory factors in body image perception. In all but one instance, no differences were found overall between the ability of obese and normal-weight subjects to detect overall changes in body size. Importantly, however, obese subjects are better at detecting changes in their body size when the image is distorted to be too thin as compared to too wide. Both obese and normal-weight men require about a 3%–7% change in the width of their body size in order to detect the change reliably. Correlations between a range of body mass index values and body size estimation accuracy indicated no relationship between these variables. Numerous studies in other laboratories asked men to place their body size into discrete categorizes, ranging from thin to obese. Researchers found that overweight and obese men underestimate their weight status, and that men are less accurate in their categorizations than are women. Cultural influences have been found to be important, with body size underestimations occurring in cultures where a larger body is found to be desirable. Methodological issues are reviewed with recommendations for future studies.

Effectiveness and feasibility of a cognitive-behavioral group intervention for body image disturbance in women with eating disorders

OBJECTIVE

The present study investigated the effectiveness and feasibility of a cognitive-behavioral group intervention for the treatment of body image disturbance in women with eating disorders.

METHOD

The study used a multiple-baseline design and enrolled 38 participants with a range of eating disorders. The intervention targeted attitudinal and behavioral components of body image disturbance using psychoeducation, self-monitoring, systematic desensitization, and cognitive restructuring. Primary outcomes included multidimensional body image assessment (effectiveness) and treatment adherence and satisfaction (feasibility).

RESULTS

Participants undergoing manualized group treatment reported significantly less body image disturbance than participants randomized to a waitlist control condition. However, differences disappeared after both groups had been through intervention. Participants also reported less depression and eating disorder pathology from baseline to posttreatment, however this difference was not considered statistically significant. Feasibility outcomes suggest the intervention was well received and highly acceptable to participants.

CONCLUSIONS

Findings emphasize the importance of adding an evidence-based body image component to standard eating disorder treatment.

Body perception and satisfaction in obese, severely obese, and normal weight female patients

The objective of this study was to investigate body perception and the associated level of dissatisfaction among obese patients. Twenty patients from each category of obese, severely obese, and normal weight individuals had their pictures enlarged or thinned using a computer program to manipulate photographs taken from the front, profile angle, and back. The pictures were shown to patients to represent both the way they thought they appeared and the way they would like to appear. Our results show that severely obese patients correctly perceived themselves as being more corpulent than obese patients, who in turn correctly perceived themselves as being more corpulent than normal weight females. These results remained stable regardless of whether the pictures were taken from the front, profile angle, or back. These results are discussed in terms of clinical and therapeutic interventions.

Assessment of adolescent body perception: development and characterization of a novel tool for morphing images of adolescent bodies

We developed a computer-based method of distorting adolescent body images, which incorporates the covariation between body parts found during growth and sexual maturation. An adolescent body-shape database (AdoBSD) and adolescent body morphing tool (AdoBMT) are described; the AdoBSD comprises real (n=320) and morphed (n approximately 41,000) images (front and side view) of 160 adolescents (9-17 years). We used a point distribution model, based upon principal components analysis, to characterize the covariation between predefined body tag-points manually positioned on the body images and to morph the body images in a realistic manner. Eight principal components (PCs) were found to characterize 96.3% of the covariation between body tag-point. Application of the PCs to the body images resulted in the manipulation of body parts including shoulder width, waist, hip, belly, thigh and calf sizes. The AdoBMT and AdoBSD may be used to investigate changes in body perception during adolescence, and the role of body perception in adolescent obesity and eating disorders. The AdoBSD is available to the research community (www.brainbody.nottingham.ac.uk).

A computer program for measuring body size distortion and body dissatisfaction

A computer program is described that measures body size distortion and body dissatisfaction. The program is written using Visual Basic development tools and will run on any Windows 98 or more current system. The width of a static digital image of the participant can be manipulated using three separate psychophysical methods. In the method of adjustment, the participant adjusts the image wider or thinner to match his or her perceived size. The participants may also be required to adjust the image to their ideal size, with the discrepancy between perceived and ideal size being used as a measure of body dissatisfaction. In the staircase method, participants see an image that is continuously expanding or contracting. The participants change the direction of the distortion when the image matches their perceived size. In the adaptive probit estimation procedure, participants judge whether a static image is distorted too wide or too thin. Analysis of the responses permits a determination of the point of subjective equality (PSE) and the difference limen (DL) values. The DL reflects the amount of body size distortion necessary for the participant to detect the distortion 50% of the time. The PSE reflects the participant's subjective judgment of his or her body size. These two values are reflective of the sensory and nonsensory components, respectively, that contribute to body size judgments.

Obesity and body image

Modern western culture emphasizes thinness, denigrates excess weight, and stigmatizes obese individuals, making it likely that obese people internalize these messages and feel badly about the physical presence that brands them. There is clear evidence that obesity is linked with poor body image, but not all obese persons suffer from this problem or are equally vulnerable. Risk factors identified thus far are degree of overweight, being female, and binge eating, with some evidence of risk increasing with early age of onset of obesity, race, and several additional factors. Treatments do exist for improving body image in overweight individuals. Key questions are how to identify those in need of body image intervention, how such programs can be integrated with weight loss treatments, and ultimately, how body image distress can be prevented.

Body size estimation: testing a new mirror-based assessment method

OBJECTIVE

The aim of the current study was to compare a new ecologically valid method of body size estimation with an existing, commonly used method.

METHOD

The new method uses a "mirror-sized" image and measures perception rather than memory of body size. Fifty-five healthy women participated in the study.

RESULTS

Body size estimations with the new method were significantly larger than with the existing method (p <.001). This difference was specific to body size and was not seen for estimation of neutral images.

DISCUSSION

The results of the study show that different body size estimations are made with the new more ecologically valid method compared with the existing method. This finding has important implications for research into the factors influencing the perception of body size.

A new ecologically valid method to assess body size estimation and body size dissatisfaction

OBJECTIVE

The primary aim of the present study was to develop an ecologically valid method for assessing the perception of body size (as opposed to the memory of body size).

METHOD

Women with clinical eating disorders (N = 14) and no eating disorder (N = 24) estimated their actual and desired body size while looking in a mirror. Estimations were made using projected images that were the same height as the participants' reflections in the mirror.

RESULTS

This new method assessed the perception of body size under conditions that resembled the real-life situation of viewing oneself in a mirror. Participants with eating disorders significantly overestimated their body size relative to controls (p <.05) and tended to be more dissatisfied with their body size (p =.07).

DISCUSSION

It is argued that the new method assesses the perception of body size, is ecologically valid, and is the most clinically relevant of the methods developed to date.

Body-size estimation by obese subjects

The present aim was to explore the body-image perception of a group of 60 hospitalized obese subjects, aged between 25 and 50 years, undergoing a weight loss treatment and 60 normal-weight persons. The 1978 modified version of the Askevold perception test by Allamani, Marasco, Michele, and Morandi was given. This nonverbal test is aimed at evaluating subjects' perception of the dimensions of different parts of the body by exploiting their projection into space. Each body area (head, the thoracic area, the abdominal area, and the pelvic area) perceived by a subject was calculated using a specifically designed software program (AREA.BASIC2); the same program was used to calculate actual body area. After obtaining the percentage deviation index for each individual [(perceived area/real area) x 100], mean values were analyzed. Obese subjects significantly underestimated the four body areas, unlike the normal weight subject who largely overestimated the abdominal and pelvic areas.

Body image assessment in anorexia nervosa patients and university students by means of video distortion: a reliability study

It is well known that anorexia nervosa is characterized by a disturbed body image. The video distortion method is one of the many methods to systematically study the perceptual aspect of this body image. Using a distorted image of her own appearance, the subject is asked to reconstruct the 'exact' measures of her body and to indicate her ideal image. The reliability of this method has been assessed in a study involving 67 anorexic patients and 105 female university students. Test--retest results within the same session and over a one-week interval were sufficiently constant. Nonetheless, for both anorexics and controls, significant differences were found between estimates with a narrowed (thin) image initially and those with a widened (fat) image initially. Both groups underestimate their body measures and only significantly differ on estimates of their ideal image, with anorexics clearly less underestimating their ideal image than students.

Effect of a mirror on body-size estimation

This study investigated the effect of mirror feedback on body-width estimation in 66 normal adolescent girls. The presence of the mirror had no substantive effect on their estimating behaviour. The authors argue that the result cast further doubt on width estimation as a valid method for accessing the internalized image of the self.