The relevance of the side-view in body image scales for public health: an example from two African populations

Development and validation of the body shape scale (BOSHAS) for assessing body shape perception in African populations

Background

As a consequence of ‘Western’ acculturation, eating disorders and body image disturbances, such as fatness phobia and body dysmorphic disorders towards musculature and body shape, are emerging in Africa, with young people the most affected. It is therefore important to accurately assess perceptions of body shape. However, the existing body image assessment scales lack sufficient accuracy and validity testing to compare body shape perception across different African populations. The purpose of this study was to develop and validate the Body Shape Scale (BOSHAS) to evaluate body shape perceptions related body image disorders in African populations.

Methods

To develop the BOSHAS, anthropometric measures of 80 Cameroonians and 81 Senegalese (both sexes included; 40.1% females overall) were taken for three body shape criteria: somatotype components, body mass index (BMI) and waist-to-hip ratio. Subjects were selected to cover a wide variability in body shape and were photographed in full face and profile positions. To validate the BOSHAS, the scale was administered twice (2 weeks apart) to 106 participants (aged 31.2 ± 12.6 years) to assess its reliability. In addition, a questionnaire measuring different aspects of body shape (e.g. musculature) was also administered (n = 597; aged 36.7 ± 15.6 years) to assess its convergent validity.

Results

The BOSHAS includes two sex-specific subscales of 10 photographs each. Most participants were able to repeat their BOSHAS preference order. Test-retest reliability was also consistent in estimating Current Body Shape (CBS), Desired Body Shape and Ideal Body Shape for participants and their partners. CBS was correlated with BMI, and different BOSHAS indices were consistent with declarations obtained by questionnaire.

Conclusions

The BOSHAS is the first sex-specific scale of real African models photographed in face and profile, including large body shape variability. The validation protocol showed good validity and reliability for evaluating body shape perceptions and dissatisfaction of Africans.

The Representation of Body Size: Variations With Viewpoint and Sex

Perceived body size is a fundamental construct that reflects our knowledge of self and is important for all aspects of perception, yet how we perceive our bodies and how the body is represented in the brain is not yet fully understood. In order to understand how the brain perceives and represents the body, we need an objective method that is not vulnerable to affective or cognitive influences. Here, we achieve this by assessing the accuracy of full-body size perception using a novel psychophysical method that taps into the implicit body representation for determining perceived size. Participants were tested with life-size images of their body as seen from different viewpoints with the expectation that greater distortions would occur for unfamiliar views. The Body Shape Questionnaire was also administered. Using a two-alternative forced choice design, participants were sequentially shown two life-size images of their whole body dressed in a standardized tight-fitting outfit seen from the front, side, or back. In one image, the aspect ratio (with the horizontal or vertical dimension fixed) was varied using an adaptive staircase, while the other was undistorted. Participants reported which image most closely matched their own body size. The staircase honed in on the distorted image that was equally likely as the undistorted photo to be judged as matching their perception of themselves. From this, the perceived size of their internal body representation could be calculated. Underestimation of body width was found when the body was viewed from the front or back in both sexes. However, females, but not males, overestimated their width when the body was viewed from the side. Height was perceived accurately in all views. These findings reveal distortions in perceived size for healthy populations and show that both viewpoint and sex matter for the implicit body representation. Though the back view of one’s body is rarely–if ever–seen, perceptual distortions were the same as for the front view. This provides insight into how the brain might construct its representation of three-dimensional body shape.

View-dependent accuracy in body mass judgements of female bodies

A fundamental issue in testing body image perception is how to present the test stimuli. Previous studies have almost exclusively used images of bodies viewed in front-view, but this potentially obscures key visual cues used to judge adiposity reducing the ability to make accurate judgements. A potential solution is to use a three-quarter view, which combines visual cues to body fat that can be observed in front and profile. To test this hypothesis, 20 female observers completed a 2-alternative forced choice paradigm to determine the smallest difference in body fat detectable in female bodies in front, three-quarter, and profile view. There was a significant advantage for three-quarter and profile relative to front-view. Discrimination accuracy is predicted by the saliency of stomach depth, suggesting that this is a key visual cue used to judge body mass. In future, bodies should ideally be presented in three-quarter to accurately assess body size discrimination.

Brazilian Photographic Figure Rating Scale for Men: Psychometric Investigation

As a follow-up to an earlier study from this research group involving women, this study examined the reliability and validity of the Brazilian Photographic Figure Rating Scale for Men (BPFRS-M) for evaluating men's body perception and dissatisfaction. In both versions of the Brazilian Photographic Figure Rating Scale (BPFRS), respondents viewed eight photographic images (seven distorted and one accurate) of themselves in standard poses and then offered self-ratings. In both versions, 10 experts assessed content validity and demonstrated high agreement (defined by ratings of 4-5 on a 5-point scale) that BPFRS items measured underlying constructs: and experts showed high (>70%) interrater agreement. For this version, participants were 149 Brazilian men (Mean = 22.4; SD = 2.7 years). Pearson correlations demonstrated convergence between the BPFRS-M and two related scales of men's body image. Positive correlations ( p = .0001) were found between actual and respondent-perceived body mass index (BMI). Test-retest and Kappa Index confirmed temporal stability. The BPFRS-M can accurately and reliably assess body perception and dissatisfaction in young men.

Development and Validation of the Body Size Scale for Assessing Body Weight Perception in African Populations

Background

The social valorisation of overweight in African populations could promote high-risk eating behaviours and therefore become a risk factor of obesity. However, existing scales to assess body image are usually not accurate enough to allow comparative studies of body weight perception in different African populations. This study aimed to develop and validate the Body Size Scale (BSS) to estimate African body weight perception.

Methods

Anthropometric measures of 80 Cameroonians and 81 Senegalese were used to evaluate three criteria of adiposity: body mass index (BMI), overall percentage of fat, and endomorphy (fat component of the somatotype). To develop the BSS, the participants were photographed in full face and profile positions. Models were selected for their representativeness of the wide variability in adiposity with a progressive increase along the scale. Then, for the validation protocol, participants self-administered the BSS to assess self-perceived current body size (CBS), desired body size (DBS) and provide a “body self-satisfaction index.” This protocol included construct validity, test-retest reliability and convergent validity and was carried out with three independent samples of respectively 201, 103 and 1115 Cameroonians.

Results

The BSS comprises two sex-specific scales of photos of 9 models each, and ordered by increasing adiposity. Most participants were able to correctly order the BSS by increasing adiposity, using three different words to define body size. Test-retest reliability was consistent in estimating CBS, DBS and the “body self-satisfaction index.” The CBS was highly correlated to the objective BMI, and two different indexes assessed with the BSS were consistent with declarations obtained in interviews.

Conclusion

The BSS is the first scale with photos of real African models taken in both full face and profile and representing a wide and representative variability in adiposity. The validation protocol proved its reliability for estimating body weight perception in Africans.