What�s the ideal female body shape, according to societal standards of beauty? The answer depends on what society you live in, and in what era. That�s because individual perceptions of attractiveness are strongly affected by culture, including what�s portrayed in art and the media.

Research indicates that the shape of a woman�s body is central to how attractive she�s perceived by heterosexual men. One way to measure body shape is body mass index (BMI), a metric computed by dividing weight by height squared. The other measure is waist-to-hip ratio (WHR), the ratio of the circumference of the waist to that of the hips. A number of studies have shown that a WHR of 0.7 is rated by heterosexual American men as being most attractive[1]. And there may be an evolutionary basis for this: other studies show that a WHR of 0.70 corresponds with health, youth, and fertility[2].

Some psychologists have gone so far as to suggest that the 0.7 ratio is a kind of universal metric of attractiveness, culturally and temporally invariant. But more recent studies have shown that beauty standards for women�s bodies are not fixed and static, but vary from culture to culture and within the same culture over time[3]. In China, for instance, a WHR of 0.6 is considered attractive[4], whereas a ratio of 0.8 is considered attractive in certain hunter-gatherer societies[5].

We can infer from art and literature what people of various time periods regarded as beautiful. For many centuries, from around 1400 to 1700, the ideal female body in Europe was round and plump, what we would today call fat. Renoir even has a painting titled �The Large Bathers.� Portraits of the women of that era depict what�s known as �rubenesque� figures, after Peter Paul Rubens, a 17th century Flemish Baroque painter who portrayed larger European women. (The mean WHR of the women depicted in Rubens� paintings has been computed to be about 0.8[6].)

In the 1800s, newspapers advertisements began to portray slimmer women as beautiful. In the 20th century, companies like Sears and Montgomery Ward distributed catalogs in which the female body was �trained� into a shapely form by bras, corsets, slips, and girdles. In the 1970s, feminist women burned their girdles (not their bras, as is commonly believed) to signify their rejection of those standards, but the ideal persisted[7].

With the rise of women�s magazines like Vogue and Ladies Home Journal and men�s magazines like Playboy, the ideal female body became even more unattainable. If we take Playboy centerfolds to be an index of men�s preferences, and compare them to the larger women popular in the 15th century, it�s clear that the waist-to-hip ratio has dramatically decreased�meaning the ideal woman went from larger and rounder to being hourglass-shaped.

But in the second half of the 20th century�again based on Playboy centerfolds�this trend has reversed itself. Several studies of Playboy models have found that in the decades that Playboy has been published, the waist size of the centerfolds has increased, even as their bust size and hip size have decreased, resulting in a higher WHR. In other words, the current ideal is a more tubular, androgynous body than the hourglass body of the 1970s[8].

But tubular doesn�t mean attainable. Even as the desired body shape became more tubular, the desired BMI continued to decrease[9]. By the 1990s, Playboy centerfolds had weights 15 percent below the weight expected for their height�a body type possessed naturally by less than 5 percent of women. The portrayed ideal is even more unattainable for most women, when you take into account that digital modification techniques are often used to make models appear thinner than they really are.

To make matters worse, women already have an exaggerated perception of how skinny men want women to be, studies have found. In one study, psychologists presented women with nine female body silhouettes, from thin to heavy. The silhouette women believed men would find most attractive was thinner than what men actually preferred. The study also found that 20 percent of women surveyed actually desired a body type even thinner than that�that is, thinner even than their exaggeratedly thin conception of what men find attractive[10].

What explains the shifts over time? No doubt our increasing awareness of the health risks of obesity has contributed to a thinner and thinner ideal. But there may be another factor at play. A study found that when times are tough economically, Playboy selected more Playboy Playmates of the Year with larger waists and waist-to-hip ratios. When social and economic conditions improved, the magazine depicted women with smaller waists and smaller waist-to-hip ratios[11].

Though it is interesting to consider what type of body a given culture considers its exemplar of beauty, computing the average measurements of Playboy centerfolds across a number of years does not imply that there is a single standard by which all women are judged. Preferences vary from one individual to the next, and one person�s �not skinny enough� is another person�s perfection.

?References?

1. Streeter, S. A., & McBurney, D. (2003). Waist-hip ratio and attractiveness: new evidence and a critique for a �critical test�. Evolution and Human Behavior, 24, 88�98.
2. Singh, D. (1993). Adaptive significance of female physical attractiveness: role of waist-to-hip ratio. Journal of Personality and Social Psychology, 65, 292�307.
3. Bovet, J., & Raymond, M. (2015). Preferred women�s waist-to-hip ratio variation over the last 2,500 Years. PLoS ONE, 10, e0123284.
4. Dixson, B.J., Dixson, A.F., Li, B., & Anderson, M.J. (2007). Studies of human physique and sexual attractiveness: Sexual preferences of men and women in China. American Journal of Human Biology, 19, 88�95.
5. Marlowe, F., Apicella, C., & Reed, D. (2005). Men�s preferences for women�s profile waist-to-hip ratio in two societies. Evolution and Human Behavior, 26, 458�468.
6. Swami, V., Gray, M., & Furnham, A. (2007). The female nude in Rubens: Disconfirmatory evidence of the waist-to-hip ratio hypothesis of female physical attractiveness. Imagination, Cognition and Personality, 26, 139�147.
7. Sentilles, R. M., & Callahan, K. (2012). Beauty over the centuries�female. In Cash, T. (Ed.). Encyclopedia of Body Image and Human Appearance: A-F. Amputations and prosthetic devices. 43-49. Amsterdam: Elsevier/Academic Press.
8. Hergovich, A., & S�ssenbach, S. (2014). The time trend of beauties: Detection of cross-cultural invariance in Playboy centerfolds. Current Psychology, 34, 666�671.
9. Voracek, M., & Fisher, M. L. (2002). Shapely centerfolds? Temporal change in body measures: trend analysis. British Medical Journal, 325, 1447�1448.
10. Fallon, A. E., & Rozin, P. (1985). Sex differences in perceptions of desirable body shape. Journal of Abnormal Psychology, 94, 102-105.
11. Pettijohn, T. F. (2004). Playboy playmate curves: Changes in facial and body feature preferences across social and economic conditions. Personality and Social Psychology Bulletin, 30, 1186�1197.