Is symmetry a visual cue to attractiveness in the human female body?

Associations of observer's gender, Body Mass Index and internalization of societal beauty ideals to visual body processing

We examined whether visual processing mechanisms of the body of conspecifics are different in women and men and whether these rely on westernised socio-cultural ideals and body image concerns. Twenty-four women and 24 men performed a visual discrimination task of upright or inverted images of female or male bodies and faces (Experiment 1) and objects (Experiment 2). In Experiment 1, both groups of women and men showed comparable abilities in the discrimination of upright and inverted bodies and faces. However, the gender of the human stimuli yielded different effects on participants’ performance, so that female faces, and male bodies appeared to be processed less configurally than female bodies and male faces, respectively. Interestingly, the reduction of configural processing for male bodies was significantly predicted by participants’ Body Mass Index (BMI) and their level of internalization of muscularity. Our findings suggest that configural visual processing of bodies and faces in women and men may be linked to a selective attention to detail needed for discriminating salient physical (perhaps sexual) cues of conspecifics. Importantly, BMI and muscularity internalization of beauty ideals may also play a crucial role in this mechanism.

Source dipole analysis reveals a new brain response to visual symmetry

Visual regularity activates a network of brain regions in the extrastriate cortex. Previous EEG studies have found that this response scales parametrically with proportion of symmetry in symmetry + noise displays. The parametric symmetry response happens in many tasks, but it is enhanced during active regularity discrimination. However, the origins and time course of this selective enhancement are unclear. Here we answered remaining questions with new source dipole analysis. As assumed, the parametric symmetry response found at the sensor level was generated by a pair of dipoles in the left and right extrastriate cortex. This bilateral activity was itself enhanced during regularity discrimination. However, we identified a third, and later, symmetry response in the posterior cingulate during regularity discrimination. Unlike the extrastriate response, this previously unknown activation only indexes strong, task relevant regularity signals. This clarifies the neural circuits which mediate the perceptual and cognitive aspects of symmetry discrimination.

Symmetry Modulates the Amplitude Spectrum Slope Effect on Visual Preference

Within the spectrum of a natural image, the amplitude of modulation decreases with spatial frequency. The speed of such an amplitude decrease, or the amplitude spectrum slope, of an image affects the perceived aesthetic value. Additionally, a human observer would consider a symmetric image more appealing than they would an asymmetric one. We investigated how these two factors jointly affect aesthetic preferences by manipulating both the amplitude spectrum slope and the symmetric level of images to assess their effects on aesthetic preference on a 6-point Likert scale. Our results showed that the preference ratings increased with the symmetry level but had an inverted U-shaped relation to amplitude spectrum slope. In addition, a strong interaction existed between symmetry level and amplitude spectrum slope on preference rating, in that symmetry can amplify the amplitude spectrum slope’s effects. A quadratic function of the spectrum slope can describe such effects. That is, preference is an inverted U-shaped function of spectrum slope whose intercept is determined by the number of symmetry axes. The modulation depth of the quadratic function manifests the interaction between the two factors.

Cognitive basis for the development of aesthetic preference: Findings from symmetry preference

Where is the visual aesthetic preference rooted from and what's its relationship with the perceptual preference that is emerging early? Do young children naturally prefer some visual stimuli or do they learn to appreciate visual stimuli for aesthetic pleasure? Here, for young preschool children who are on the age that the preferences are developing, we provide findings from a study to show that the interplay between early emerging perceptual sensitivity and perceptual exposure promotes the emergence of preschool children's aesthetic preferences for simple visual patterns. Specifically in the experiments, 4-year-old children were exposed to either symmetric or asymmetric non-figurative forms in a perceptually demanding game; the group of children who received exposure to symmetric patterns showed aesthetic preference to the exposed patterns, while no preference was found in the group that received exposure to asymmetric patterns. The following recognition test then showed that the symmetric objects were differentiated better and remembered more clearly by the children, indicating that the symmetry was perceptually encoded better. These findings suggest that the early emerging perceptual sensitivity to 'good features' such as symmetry provides the prior cognitive prerequisites, allowing visual perceptual exposure to nourish the eventual formation of aesthetic preference. Thus, the preferences for aesthetic appreciation are likely the outcome of the interplay between biological and ecological adaptation.

Male Figural Rating Scales: A Critical Review of the Literature

Figural rating scales are tools used to measure male body dissatisfaction. The present review aimed to examine the design and psychometric properties of male figural rating scales and make recommendations based on findings. Relevant databases were systematically searched for studies that had developed and validated male figural rating scales. Twenty studies were included in this review. Figural rating scales differed in terms of the number of images represented and type of stimuli used (hand-drawn silhouettes, hand-drawn figures, computer-rendered figures, and photograph figures). Reliability and validity evidence varied greatly in strength across all scales. Four of the 20 scales included a correlational analysis between figural rating scale scores and eating disorder symptoms. Results showed the moderate to high positive correlations between eating disorder symptoms and figural rating scale perceived and index scores, suggesting that figural rating scales are sensitive to detecting eating disorder symptoms. Ideally, male figural rating scales should show strong validity and reliability, include variations in both body fat and muscularity, utilise realistic body stimuli, and be interval scales. No existing male figural rating scale meets these criteria. However, this review identifies five figural rating scales that meet the majority of the recommended criteria.

Anticipatory Defocusing of Attention and Contextual Response Priming but No Role of Aesthetic Appreciation in Simple Symmetry Judgments when Switching between Tasks

Visual attention can be adjusted to task requirements. We asked participants to switch between judging the symmetry of vertically presented three-letter strings and identifying the central stimulus (i.e., Eriksen task) to investigate anticipatory adjustment of attention. Our experiments provide evidence for anticipatory adjustment of visual attention, depending on the cued task (i.e., focusing and defocusing of attention after the Eriksen task cue and after the symmetry task cue, respectively). Although, symmetry judgments were, overall, considerably slower than the identification of the central letter, the effects of response congruency between tasks were comparable in the two tasks, which suggested strong response priming from concurrent symmetry judgment in Eriksen task trials. Symmetry judgment performance was best for homogeneous letter strings (e.g., HHH), worst for strings that were symmetrical and inhomogeneous (e.g., XHX), and intermediate for asymmetrical strings (e.g., HHX). The difficulty of categorizing symmetrical-inhomogeneous items markedly deviated from the aesthetic ratings of the stimuli, displaying a pronounced preference for symmetrical strings, but only little difference among the symmetrical items, and might be accounted by conflict with response priming based on inhomogeneity detection. Although our study provides little evidence for an effect of aesthetic appreciation in simple symmetry judgments, it demonstrates the strong role of contextual dependencies.

The Role of Regional Contrast Changes and Asymmetry in Facial Attractiveness Related to Cosmetic Use

This study collected behavioral data for testing how regional contrast changes due to the addition of cosmetics would affect attractiveness ratings. In addition, we used an established model of asymmetry to look for a correlation between changes in attractiveness related to the application of cosmetics to specific regions of the face and changes in symmetry. Using this asymmetry model we compared female faces with and without makeup. Specifically, we used a highly controlled set of grayscale faces in which makeup application was standardized to explore these issues from a perceptual perspective. The human data showed that adding upper eye makeup significantly increased attractiveness ratings. In contrast, increases in contrast to the lower eyes and lips did not lead to increases in attractiveness ratings; application of cosmetics to the lower eyes led to a significant decrease in attractiveness. We found that for the makeup condition that led to increased attractiveness, asymmetry did not change significantly when makeup was applied to the female faces. This suggests a role for mechanisms other than symmetry related to increases in attractiveness related to makeup use in females.

Visual Body Scale for Men (VBSM): Validation of a new figural rating scale to measure perceived-desired body discrepancy in men

OBJECTIVES

This study examined the psychometric properties of the Visual Body Scale for Men (VBSM), a new figural rating scale designed as a measure of male perceived-ideal body discrepancy.

METHODS

In Study 1, participants were 133 males who selected their perceived and desired bodies from the VBSM. Body composition, body dissatisfaction, eating disorder and depressive symptomatology were obtained. In Study 2, participants were 33 males who completed the VBSM and the Bodybuilder Image Grid (BIG). Study 2 aimed to compare the validity evidence of the VBSM to the BIG.

RESULTS

Both VBSM-Body Fat (VBSM-BF) and VBSM-Muscularity (VBSM-M) demonstrated sound test-retest reliability, convergent, concurrent, and discriminant validity evidence. Additionally, the VBSM demonstrated better sensitivity for detecting body fat-related body image and dissatisfaction when compared to the BIG.

CONCLUSION

The VBSM improves upon existing male figural rating scales in terms of image quality, includes both dimensions of a male body image, and demonstrates good psychometric properties.

Eye Movements When Looking at Potential Friends and Romantic Partners

Eye movements of 105 heterosexual undergraduate students (36 males) were monitored while viewing photographs of men and women identified as a potential mate or a potential friend. Results showed that people looked at the head and chest more when assessing potential mates and looked at the legs and feet more when assessing potential friends. Single people looked at the photographs longer and more frequently than coupled people, especially when evaluating potential mates. In addition, eye gaze was a valid indicator of relationship interest. For women, looking at the head corresponded to greater interest in friendship, whereas for men looking at the head corresponded to less interest in friendship. These findings show that relational goals and gender may affect the way people scan their environment and search for relevant information in line with their goals.

A Gaze-Driven Evolutionary Algorithm to Study Aesthetic Evaluation of Visual Symmetry

Empirical work has shown that people like visual symmetry. We used a gaze-driven evolutionary algorithm technique to answer three questions about symmetry preference. First, do people automatically evaluate symmetry without explicit instruction? Second, is perfect symmetry the best stimulus, or do people prefer a degree of imperfection? Third, does initial preference for symmetry diminish after familiarity sets in? Stimuli were generated as phenotypes from an algorithmic genotype, with genes for symmetry (coded as deviation from a symmetrical template, deviation–symmetry, DS gene) and orientation (0° to 90°, orientation, ORI gene). An eye tracker identified phenotypes that were good at attracting and retaining the gaze of the observer. Resulting fitness scores determined the genotypes that passed to the next generation. We recorded changes to the distribution of DS and ORI genes over 20 generations. When participants looked for symmetry, there was an increase in high-symmetry genes. When participants looked for the patterns they preferred, there was a smaller increase in symmetry, indicating that people tolerated some imperfection. Conversely, there was no increase in symmetry during free viewing, and no effect of familiarity or orientation. This work demonstrates the viability of the evolutionary algorithm approach as a quantitative measure of aesthetic preference.

Attractiveness is influenced by the relationship between postures of the viewer and the viewed person

Many factors influence physical attractiveness, including degree of symmetry and relative length of legs. We asked a sample of 112 young adults to rate the attractiveness of computer-generated female bodies that varied in terms of symmetry and leg-to-body ratio. These effects were confirmed. However, we also varied whether the person in the image was shown sitting or standing. Half of the participants were tested standing and the other half sitting. The difference in the posture of the participants increased the perceived attractiveness of the images sharing the same posture, despite the fact that participants were unaware that their posture was relevant for the experiment. We conclude that our findings extend the role of embodied simulation in social cognition to perception of attractiveness from static images.

Eye of the Beholder: Symmetry Perception in Social Judgments Based on Whole Body Displays

External bilateral symmetry is a biological marker of normal development and is considered a signal of health and attractiveness across species. Because most human interactions are dynamic, it was hypothesized that observers would be able to perceive spatiotemporal symmetry—symmetry in motion—in human point-light walkers. It was also hypothesized that observers would rate symmetrical walkers as healthy and attractive. Symmetrical and asymmetrical figures were presented to adult participants ( n = 22) in motion and as static images with motion implied. Static symmetry was readily perceived, and symmetrical figures were judged significantly healthier and more attractive than asymmetrical figures. However, observers were unable to discriminate symmetry in dynamic presentations. These data provide preliminary evidence of a temporal summation window for a dynamic symmetry perception.

Eye of the beholder: Symmetry perception in social judgments based on whole body displays

External bilateral symmetry is a biological marker of normal development and is considered a signal of health and attractiveness across species. Because most human interactions are dynamic, it was hypothesized that observers would be able to perceive spatiotemporal symmetry-symmetry in motion-in human point-light walkers. It was also hypothesized that observers would rate symmetrical walkers as healthy and attractive. Symmetrical and asymmetrical figures were presented to adult participants (n = 22) in motion and as static images with motion implied. Static symmetry was readily perceived, and symmetrical figures were judged significantly healthier and more attractive than asymmetrical figures. However, observers were unable to discriminate symmetry in dynamic presentations. These data provide preliminary evidence of a temporal summation window for a dynamic symmetry perception.

Determinants of Hand Attractiveness—A Study Involving Digitally Manipulated Stimuli

Although attractiveness of the human hand is of significance in the social and mating context, thus far it has attracted little scientific interest. In this study, young women and men were presented with pairs of digitally manipulated images of opposite-sex hands and asked to indicate the hand perceived to be the more attractive in each pair. The hands within a pair differed from one another by a single feature: shape averageness, femininity, finger length, second-to-fourth-digit ratio, or skin smoothness. All these features, with the exception of the digit ratio, were shown to increase hand attractiveness in each sex in both dorsal and ventral views. Skin smoothness was preferred more strongly in female than in male hands. Women also tended to prefer medium degrees of shape femininity and skin smoothness in male hands compared to both high and low levels. Adaptive and non-adaptive (related to perceptual bias) mechanisms underlying these preferences are discussed.

An explanation for enhanced perceptions of attractiveness after alcohol consumption

Acute alcohol consumption increases ratings of attractiveness to faces. This may help to explain increased frequencies of sexual encounters during periods of alcohol intoxication. At least in part, such increased attraction may be the result of alcohol consumption decreasing ability to detect bilateral asymmetry, presumably because of the reductions in the levels of visual function. We tested the hypotheses that acute alcohol consumption decreases ability to detect asymmetry in faces and reduces preference for symmetrical faces over asymmetrical faces. Twenty images of a pair of faces and then 20 images of a single face were displayed on a computer, one at a time. Participants were instructed to state which face of each of the face pairs displayed was most attractive and then whether the single face being displayed was symmetrical or not. Data were collected near campus bars at Roehampton University. Sixty-four self-selecting students who undertook the study were classified as either sober (control) or intoxicated with alcohol. For each face pair or single face displayed, participant response was recorded and details of the alcohol consumption of participants that day were also obtained. Sober participants had a greater preference for symmetrical faces and were better at detecting whether a face was symmetrical or otherwise, supporting the hypotheses. A further, unexpected finding was that males made fewer mistakes than did females when determining whether individual faces were asymmetrical. The reduced ability of inebriated people to perceive asymmetry may be an important mechanism underlying the higher ratings of facial attractiveness they give for members of the opposite sex and hence their increased frequency of mate choice.

The thickness of the ligamentum flavum in relation to age and gender

Hypertrophy of the ligamentum flavum (LF) can reduce the diameter of the spinal canal posteriorly. Such stenosis may significantly compress the dural sac and nerve roots, resulting in symptoms, even without a bulging anulus fibrosus or herniated nucleus pulposus. We conducted an anatomical study to determine the influence of age and gender on the thickness of the LF at the lower lumbar levels using magnetic resonance imaging (MRI). The thickness of 1,280 ligaments was determined at the L4-L5 and L5-S1 levels from MRIs. We screened 320 patients (152 males [47.5%] and 168 females [52.5%]) between 21 and 82 years of age. There were no significant differences in LF thickness with respect to gender (P > 0.05). Age was not correlated with the thicknesses of the LF. The left LF at the L4-L5 and L5-S1 levels was significantly thicker than on the right side (P < 0.05). Furthermore, the LF thicknesses at L5-S1 bilaterally were significantly greater than on the corresponding sides at L4-L5 (P < 0.05). The LF is an important anatomical structure, which might cause low back or leg pain. Therefore, the thickness of the LF should be measured and evaluated carefully in the case of spinal stenosis.

Signals of Genetic Quality and Maternal Investment Capacity: The Dynamic Effects of Fluctuating Asymmetry and Waist-to-Hip Ratio on Men’s Ratings of Women’s Attractiveness

Fluctuating asymmetry (FA) and waist-to-hip ratio (WHR) are frequently studied physical attractiveness variables in social and evolutionary psychology. FA represents deviations in bilateral symmetry—differences between left and right body parts. WHR is the ratio of the smallest part of the waist to the largest part of the hips. Although FA and WHR are important mate preference criteria, research has not examined their joint influence on attraction. Thus, 140 heterosexual male undergraduates ranked—and 118 rated—the attractiveness of 10 photographs of rear-facing nude women. Women’s FA and WHR were negatively related to attractiveness separately, after controlling for each other and after controlling for body mass index (BMI). An FA × WHR interaction emerged, such that men’s preferences for lower WHRs increased as FA decreased, even after controlling for BMI. FA and WHR affected attractiveness in ways consistent with the information they carry and its likely effects on offspring quality.

Quantifying female bodily attractiveness by a statistical analysis of body measurements

BACKGROUND

To investigate what makes a female figure attractive, an extensive experiment was conducted using high-quality photographic stimulus material and several systematically varied figure parameters. The objective was to predict female bodily attractiveness by using figure measurements.

METHODS

For generating stimulus material, a frontal-view photograph of a woman with normal body proportions was taken. Using morphing software, 243 variations of this photograph were produced by systematically manipulating the following features: weight, hip width, waist width, bust size, and leg length. More than 34,000 people participated in the web-based experiment and judged the attractiveness of the figures. All of the altered figures were measured (e.g., bust width, underbust width, waist width, hip width, and so on). Based on these measurements, ratios were calculated (e.g., waist-to-hip ratio). A multiple regression analysis was designed to predict the attractiveness rank of a figure by using figure measurements.

RESULTS

The results show that the attractiveness of a woman's figure may be predicted by using her body measurements. The regression analysis explains a variance of 80 percent. Important predictors are bust-to-underbust ratio, bust-to-waist ratio, waist-to-hip ratio, and an androgyny index (an indicator of a typical female body).

CONCLUSIONS

The study shows that the attractiveness of a female figure is the result of complex interactions of numerous factors. It affirms the importance of viewing the appearance of a bodily feature in the context of other bodily features when performing preoperative analysis. Based on the standardized beta-weights of the regression model, the relative importance of figure parameters in context of preoperative analysis is discussed.

Fluctuating asymmetry and preferences for sex-typical bodily characteristics

Body size and shape seem to have been sexually selected in a variety of species, including humans, but little is known about what attractive bodies signal about underlying genotypic or phenotypic quality. A widely used indicator of phenotypic quality in evolutionary analyses is degree of symmetry (i.e., fluctuating asymmetry, FA) because it is a marker of developmental stability, which is defined as an organism's ability to develop toward an adaptive end-point despite perturbations during its ontogeny. Here we sought to establish whether attractive bodies signal low FA to observers, and, if so, which aspects of attractive bodies are most predictive of lower FA. We used a 3D optical body scanner to measure FA and to isolate size and shape characteristics in a sample of 77 individuals (40 males and 37 females). From the 3D body scan data, 360 degrees videos were created that separated body shape from other aspects of visual appearance (e.g., skin color and facial features). These videos then were presented to 87 evaluators for attractiveness ratings. We found strong negative correlations between FA and bodily attractiveness in both sexes. Further, sex-typical body size and shape characteristics were rated as attractive and correlated negatively with FA. Finally, geometric morphometric analysis of joint configurations revealed that sex-typical joint configurations were associated with both perceived attractiveness and lower FA for male but not for female bodies. In sum, body size and shape seem to show evidence of sexual selection and indicate important information about the phenotypic quality of individuals.

Success is all in the measures: androgenousness, curvaceousness, and starring frequencies in adult media actresses

The debate of whether body-mass index (BMI) or waist-to-hip ratio (WHR) is the primary visual cue to female physical attractiveness (FPA) has generated considerable interest. However, experiments addressing this question typically have limited ecological validity and do not capture the ultimate goal of FPA, which is to elicit male sexual arousal. Hence, using an unobtrusive measures design, we retrieved movie and magazine starring frequencies of 125 adult media actresses from a company's database, operationalized starring frequencies as FPA measures, and tested their relationship to actresses' anthropometric data. Low BMI was related to frequent movie starring, while WHR, waist-to-bust ratio (WBR), and bust size were not. Conversely, low WHR, low WBR, and larger bust size were related to frequent magazine starring, while BMI was not. Visual cues to FPA might be domain-specific, with androgenousness cues salient for attractiveness evaluation of moving bodies and curvaceousness cues salient for posing bodies.

Perceptual adaptation affects attractiveness of female bodies

We investigated whether short durations (5 minutes) of exposure to distorted bodies can change subsequent perceptions of attractiveness and normality. Participants rated 110 female bodies, varying in width, on either their attractiveness or normality before and after exposure to either extremely narrow (-50% of original width in Experiments 1 and 2) or extremely wide bodies (+50% of original width in Experiment 1, and +70% of original width in Experiment 2). In both experiments, the most attractive and most normal looking bodies became significantly and substantially narrower after exposure to narrow bodies. The most normal looking body changed significantly after exposure to wide bodies, but the most attractive body did not. These results show that perceptions of body attractiveness can be influenced by experience, but that there is an asymmetry between the effects of exposure to narrow and wide bodies. We consider a possible mechanism for this unexpected asymmetry, as well as possible implications for the effects of media exposure on body-image. The most attractive body shape was consistently narrower than the most normal looking body shape. Substantial changes in what looked normal were accompanied by congruent changes in what looked attractive, suggesting that a normal or average body shape may function as a reference point against which body attractiveness is judged.

Physical Attractiveness and Health in Western Societies: A Review

Evidence from developed Western societies is reviewed for the claims that (a) physical attractiveness judgments are substantially based on body size and shape, symmetry, sex-typical hormonal markers, and other specific cues and (b) physical attractiveness and these cues substantially predict health. Among the cues that the authors review, only female waist-to-hip ratio and weight appear to predict both attractiveness and health in the claimed manner. Other posited cues--symmetry and sex-typical hormonal markers among them--failed to predict either attractiveness or health (or both) in either sex. The authors find that there is some indication that attractiveness has an overall relationship with health among women, but little indication that male attractiveness relates to male health.

Predominantly extra-retinotopic cortical response to pattern symmetry

Symmetry along one or more axes is a key property of objects and biological organisms. We report on a bilateral visual region of occipital cortex that responds strongly to the presence of multiple symmetries in the viewed image. The stimuli consisted of random dots organized in fourfold and onefold mirror-symmetric patterns, against random control stimuli. The contrast between symmetric and random patterns produced negligible or inconsistent activation of the primary visual projection area V1 or of other medial occipital projection areas. However, there was strong symmetry-specific activation in extra-retinotopic lateral occipital cortex. The high level of activation in this region of cortex may represent part of a general class of computations that require integration of information across a large span of the visual field.

Human female attractiveness: waveform analysis of body shape

Two putative cues to female physical attractiveness are body mass index (BMI) and shape (particularly the waist-hip ratio or WHR). To determine the relative importance of these cues we asked 23 male and 23 female undergraduates to rate a set of 60 pictures of real women's bodies in front-view for attractiveness. In our set of images, the relative ranges of BMI and WHR favoured WHR. We based these ranges on a sample of 457 women. We did not limit the WHR range, although we kept the BMI range to 0.5 s.d. either side of the sample means. As a result, WHR averaged 1.65 s.d. either side of its sample mean. However, even with these advantages, WHR was less important than BMI as a predictor of attractiveness ratings for bodies. BMI is far more strongly correlated with ratings of attractiveness than WHR (BMI approximately 0.5, WHR approximately 0.2). To further explore the relative importance of BMI and WHR, we deliberately chose a subset of these images that demonstrated an inverse correlation of BMI and WHR (i.e. a group in which as images get heavier they also become more curvaceous). If WHR is the most important determinant of attractiveness, then the more curvaceous (but higher BMI) images should be judged most attractive. However, if BMI is a better predictor, then the opposite should be true. We found that the more curvaceous (but higher BMI) images were judged least attractive, thereby inverting the expected rating pattern. This strongly suggests that viewers' judgements were influenced more by BMI than WHR. Finally, it is possible that body shape is an important cue to attractiveness, but that simple ratios (such as WHR) are not adequately capturing it. Therefore, we treated the outline of the torso as a waveform and carried out a set of waveform analyses on it to allow us to quantify body shape and correlate it with attractiveness. The waveform analyses address the complexity of the whole torso shape, and reveal innate properties of the torso shape and not shape elements based on prior decisions about arbitrary physical features. Our analyses decompose the waveform into objective quantified elements whose importance in predicting attractiveness can then be tested. All of the components that were good descriptors of body shape were weakly correlated with attractiveness. Our results suggest that BMI is a stronger predictor of attractiveness than WHR.

Maternal waist-to-hip ratio does not predict child gender

It has been suggested that a high pre-conceptual waist-to-hip ratio (WHR) is a good predictor of male offspring and, thus, in cultures that value male children, an androgenous body shape may be judged as most attractive. The predictive value of WHRs is based on studies measuring women who already have children and correlating their WHRs with the proportion of existing male offspring. However, carrying a male child may alter WHRs in a different way to carrying a female child, and a high WHR may be an effect rather than a cause of male offspring. In order to test the predictive power of a pre-conceptual WHR and offspring gender, we took WHR measures from 458 women who intended to become pregnant and then correlated this with the genders of their subsequent children. We found no significant correlation. It is therefore not clear why a high WHR is preferred in some cultures. We suggest that differences in attractiveness preferences between different ethic groups are actually based on weight scaled for height (the body mass index or BMI) rather than the WHR since although there will be a preferred optimal BMI for each ethnic group, which will balance environmental and health factors, this optimal BMI may differ between groups and environments.

The estimation of body mass index and physical attractiveness is dependent on the observer's own body mass index

A disturbance in the evaluation of personal body mass and shape is a key feature of both anorexia and bulimia nervosa. However, it is uncertain whether overestimation is a causal factor in the development of these eating disorders or is merely a secondary effect of having a low body mass. Moreover, does this overestimation extend to the perception of other people's bodies? Since body mass is an important factor in the perception of physical attractiveness, we wanted to determine whether this putative overestimation of self body mass extended to include the perceived attractiveness of others. We asked 204 female observers (31 anorexic, 30 bulimic and 143 control) to estimate the body mass and rate the attractiveness of a set of 25 photographic images showing people of varying body mass index (BMI). BMI is a measure of weight scaled for height (kg m(- 2)). The observers also estimated their own BMI. Anorexic and bulimic observers systematically overestimated the body mass of both their own and other people's bodies, relative to controls, and they rated a significantly lower body mass to be optimally attractive. When the degree of overestimation is plotted against the BMI of the observer there is a strong correlation. Taken across all our observers, as the BMI of the observer declines, the overestimation of body mass increases. One possible explanation for this result is that the overestimation is a secondary effect caused by weight loss. Moreover, if the degree of body mass overestimation is taken into account, then there are no significant differences in the perceptions of attractiveness between anorexic and bulimic observers and control observers. Our results suggest a significant perceptual overestimation of BMI that is based on the observer's own BMI and not correlated with cognitive factors, and suggests that this overestimation in eating-disordered patients must be addressed directly in treatment regimes.