Gene Expression has a post on changing preferences for hair color over time. The hair color of Playboy playmates was charted from 1954 to 2007, on the assumption that this monthly series reflects male sexual tastes. It turns out that the percentage of blonde playmates has risen over the years: from a low of about 35% in the mid-1960s to a high of 60% around the year 2000. A similar study was done fifteen years ago, with similar results (Rich & Cash, 1993).
These proportions are well above the actual proportion of blonds among white Americans. When Rich and Cash (1993) studied a sample of undergraduates, the proportions were 68.1% brunette, 26.8% blond, and 5.1% red. This breakdown parallels those put forward in two British studies: 68% brunette, 25% blond, 1% red, and 6% black (Takeda et al., 2006); and 74% brunette; 18% blond, and 8% red (Mather et al., unpublished). Jason Malloy says a similar breakdown appears in Beddoe (1885).
Thus, blond hair preference does not reflect the actual distribution of hair color. In fact, in light of current demographic trends, the scarcer blondes become, the more they seem to be preferred.
This frequency dependence has been shown in humans. Thelen (1983) presented male participants with slides showing attractive brunettes and blondes and asked them to choose, for each series, the woman they would most like to marry. One series had equal numbers of brunettes and blondes, a second 1 brunette for every 5 blondes, and a third 1 brunette for every 11 blondes. Result: the rarer the same brunette was in a series, the likelier the men would choose her.
Just as blondes are more strongly preferred as they become scarcer, they seem to be less popular when more abundant. Havelock Ellis (1928, pp. 182-183) noted a weaker preference for blonde women in England than in France, which he ascribed to the higher prevalence of blondness among the English.
Indeed, if this preference were not frequency-dependent, sexual selection should have steadily increased the incidence of blond hair, to the point of eliminating all other colors. Yet blonds do not form the majority of any human population. Even Swedes are no more than 40% blond, and this is using a definition that already includes a variety of shades (platinum blond, ash blond, sunny blond, sandy blond, golden blond, strawberry blond, zebra blond, dirty blond, brownish blond, see Wikipedia article).
In addition to America’s changing demographics, the rise of the blonde playmate may also reflect the spread of Playboy magazine into American Catholic communities where it was initially excluded and where blond hair is less common (many of these communities being of southern European origin). In the wake of Vatican II (1962-1965), Catholic Americans have adopted increasingly secular attitudes towards sex, and consumption of soft porn has become less stigmatized, if not tolerated.
Beddoe, J. (1885). The Races of Britain: A Contribution to the Anthropology of Western Europe, Arrowsmith, Bristol & Trübnermm, London.
Ellis, H. (1928). Studies in the Psychology of Sex. Vol. IV, "Sexual Selection in Man." Philadelphia: F.A. Davis Company.
Mather, F., Manning, J.T., & Bundred, P.E. (unpublished). 2nd to 4th digit ratio, hair and eye colour in Caucasians: Evidence for blond hair as a correlate of high prenatal oestrogen.
Rich, M.K., & Cash, T.F. (1993). The American image of beauty: Media representations of hair color for four decades. Sex Roles, 29, 113-124.
Takeda, M.B., Helms, M.M., & Romanova, N. (2006). Hair color stereotyping and CEO selection in the United Kingdom. Journal of human behavior in the social environment, 13, 85-99
Thelen, T.H. (1983). Minority type human mate preference. Social Biology, 30, 162-180.