Seven tenths incorrect: heterogeneity and change in the waist-to-hip ratios of Playboy centerfold models and Miss America pageant winners - Statistical Data Included

Journal of Sex Research, May, 2002 by Jeremy Freese, Sheri Meland

We seek to correct what appears to be an emerging "academic urban legend" (Tooby & Cosmides, 2000) regarding the stability and precision of what heterosexual males find sexually attractive. The academic urban legend in question is that there has been a remarkable consistency in the waist-to-hip ratios (WHR) of both Playboy centerfolds and winners of the Miss America pageant. Because these women are taken as representative icons of venerated beauty standards, this supposed consistency has been taken by some authors as prima facie evidence of an evolved basis for this very specific preference, although that claim would seem to be refuted by studies that have failed to find the preference in societies whose conditions resemble those of our Pleistocene ancestors far more closely than our own (Wetsman & Marlowe, 1999; Yu & Shepard, 1998). There is also dispute about the validity of the arguments that have been made for why such a preference would have been adaptive in the environments of our evolutionary past (Wetsman, 1998). We do not pursue these points here; what we dispute are the empirical assertions that have been made about the WHR of these supposed twin pillars of American beauty: Playboy Playmates and Miss Americas. The data presented below demonstrates both that the WHR has been more variable than others have suggested and that the average WHR has in fact changed in what seems to us to be a consistent fashion over time.

Before presenting these data, however, we need to establish that the incipient academic urban legend does exist. We submit four examples, which in no way should be taken as exhaustive:

1. From Buss's (1999) Evolutionary Psychology textbook; virtually the same two sentences also appear in Buss and Kenrick's (1998, p. 1000) review of evolutionary psychology for the Handbook of Social Psychology (1):

   Singh's analysis of Playboy centerfolds and winners of U.S. beauty contests
   over the past thirty years confirmed the invariance of this cue. Although
   both centerfolds and beauty contest winners got slightly thinner over that
   period, their WHRs remained exactly the same, at 0.70. (p. 144)

2. From the book Mean Genes, by economist Terry Burnham and biologist Jay Phelan (2000):

   Although the bodies of [Miss America] winners are sometimes larger and
   sometimes smaller over the decades, their hourglass shape never varies. In
   particular, when the waist measurement is divided by the hip measurement
   for more than sixty Miss Americas from the 1920's to the 80's, the
   calculation never deviates from the tight range of 0.69-0.72. (p. 142)

3. From psychologist Nancy Etcoff's (1999) Survival of the Prettiest: The Science of Beauty:

   Looking at Miss Americas from the 1920s through the 1980s and at Playboy
   from 1955 to 1965 and 1976 to 1990, [Singh] found Miss Americas'
   waist-to-hip ratios varied only within the .72 to .69 mark, and Playboy
   models within the .71 to .68 range. (p. 193)

4. From a Newsweek article by Geoffrey Cowley (2000), which has since been reprinted as part of an anthology for social psychology students:

   Singh's findings suggest the fashion won't change any time soon. In one
   study, he compiled the measurements of Playboy centerfolds and Miss America
   winners from 1923 to 1990. Their bodies got measurably leaner over the
   decades, yet their waist-hip ratios stayed within the narrow range of .68
   to .72. (2) (p. 193)

As for the source of these assertions, all of the above either explicitly cite or seem to be relying on Singh (1993), who writes:

   WHR for Playboy centerfolds increased slightly from .68 to .71 over the
   years examined, whereas Miss America contest winners had WHR decrease from
   .72 to .69 (Figure 1). Thus, WHR of both the Miss America contest winners
   and the Playboy centerfolds, in spite of reduction of body weight over the
   years, remained within the .68 to .72 range. (p. 296)

[FIGURE 1 OMITTED]

To our eyes, this claim would actually seem to be contradicted by the Figure 1 that is provided in Singh (1993, p. 297); in other words, despite the frequent repetition of Singh's assertion by academics and others, the warrant for it is not even apparent to us from the information available in the original paper. The interpretation of the above statement that makes the most sense to us is that when Singh is talking about increases and decreases over time--as well as about the range--he is talking about the predicted WHR values from a fitted regression line. However, saying the predicted values of a dependent variable change little over the range of an independent variable is mainly a claim about the strength of the association and does not necessarily imply anything about the actual range of the dependent variable, even though the latter seems to be the prevailing interpretation that has been made of the results by others.

In any event, to try to clear the matter up decisively, we have independently reassembled and updated data on both pageant winners and Playboy centerfolds; as we explain below, in both cases the data we use can be thought to surpass the quality of that used by Singh. (3) The analysis below provides results that show both the extent of the range of WHR of these putative icons of beauty and provide a different view of how WHR has changed over time.