Gilbert Blythe tormenting Anne Shirley (Anne of Green Gables)Male preference for female hair color seems to be frequency-dependent. The less common a hair color becomes, the more it is preferred. When male subjects are presented with a series of photos showing blondes and brunettes, preference for any one brunette is inversely proportional to the number of brunettes in the series (Thelen, 1983). This frequency dependence may explain why blonde hair is less strongly preferred in England than in France.
England is, however, somewhat fairer generally than most parts of Europe; so that, while it may be said that a very beautiful woman in France or Spain may belong to the blondest section of the community, a very beautiful woman in England, even though of the same degree of blondness as her Continental sister, will not belong to the extremely blonde section of the English community. (Ellis, 2007[1905], p. 160)
Hair color is normally a minor factor when men select mates. It becomes a major factor only when the level of sexual selection is intense, like the situation of a movie producer who has to choose one actress from a number of excellent candidates. Under such conditions, relatively unimportant factors can make a big difference, especially those that can attract and retain attention.
I’ve argued that such conditions once prevailed among ancestral Europeans, specifically European women (Frost, 1994, 2006, 2008). One result was an ever broader range of eye and hair colors. Whenever a new color appeared through mutation, it would be favored by sexual selection until it had become as frequent as the other colors. Although the pressure of sexual selection was on women, these changes in physical appearance spilled over on to men, thereby creating a new phenotype in both sexes.
But we still see some evidence that this selection pressure had targeted women. A twin study has shown that hair is, on average, lighter-colored in women than in men, with red hair being especially more frequent in females. Women also show greater variation in hair color (Shekar et al., 2008).
Do redheads have less fun?
Red is the least common of these new hair colors. It also seems to have a lower tipping point where preference gives way to non-preference—if not dislike. Indeed, in comparison to blondes, redheads become more easily the butt of ridicule and prejudice.
How come? Several reasons appear in the literature. One is that Judas, the betrayer of Christ, was red-haired. Yet this association of ideas may have originated in a much older one that the Church later recycled for its own purposes:
There can be little doubt that this tradition is simply the application of the old belief—much older than Judas Iscariot—that red-haired men are treacherous and dangerous, to the Arch-traitor, sometime during the early Middle Ages, when the popular imagination was busy making up biographies and biographical details for the saints and martyrs of the Church. (Baum, 1922)
This older folk belief had its basis in the idea that redheads are hotheaded and not to be trusted:
We must look further for an explanation of Judas color, and specially in the ill-omen of red hair. This itself took its beginning no doubt, like so much else of popular tradition, in the shrewd observation of natural phenomena. The common German proverb, "Roter Bart, untreue Art," represents a condensed popular judgment. Even to-day a red-haired man is assumed to be hot-headed and quick-tempered, and so not quite to be counted on. (Baum, 1922)
Is this true? Perhaps. Of all the different hair colors, red is the one that seems to have the most pleiotropic effects, e.g., skin type, freckling, beard color, etc. (Flanagan et al., 2000). There are also physiological consequences. Redheads seem to be more sensitive to painkillers, the effect being stronger in women than in men (Mogil et al., 2003). This increased sensitivity was noted over sixty years ago:
Dr. Paul M. Wood, Secretary-Treasurer of the American Board of Anaesthesiology, writes, " ... in twenty-two years of personal experience I have discovered that many difficulties have occurred with persons who have red hair. They do not seem to take anaesthetics in the same way that others do. Most of them are much more sensitive to the anaesthetic."
Dr. David M. Levy states that red headed persons in general go under anaesthetic more readily than do persons of other pigmentations.
Dr. Marco Nunez confirms these observations that red heads are affected more readily than are other persons. (Keeler, 1947)
We may have here one reason why red hair never became as common as other hair colors. There were too many side effects, and natural selection has probably not had enough time to iron them all out.
But culture has probably been just as important in determining the frequency of red hair. Whereas attitudes to red hair tend to be negative in Latin cultures, they are generally positive in Celtic cultures, as Curry (1916, pp. 18-19) notes in his study of medieval literature: “It is worthy of note, however, that in the Old Irish and Welsh red hair seems to be appreciated, tho to a less extent than the blonde.”
The last point is interesting because the frequency of red hair is much higher in the Celtic regions of Europe (Wikipedia). Has this prevalence been maintained at a higher level by a more “redhead-friendly” environment?
References
Baum, P.F. (1922). Judas's red hair, The Journal of English and Germanic Philology, 21, 520-529.
Curry, W.C. (1916). The Middle English Ideal of Personal Beauty, as found in the Metrical Romances, Chronicles, and Legends of the XIII, XIV, and XV Centuries. Baltimore: J.H. Furst Co.
Ellis, H. (2007 [1905]). Studies in the Psychology of Sex, Volume 4 (of 6), Teddington, Echo Library.
Flanagan, N., E. Healey, A. Ray, S. Philips, C. Todd, I.J. Jackson, M.A. Birch-Machin, & J.L. Rees. (2000). Pleiotropic effects of the melanocortin 1 receptor (MC1R) gene on human pigmentation, Human Molecular Genetics, 9, 2531-2537.
Frost, P. (2008). Sexual selection and human geographic variation, Special Issue: Proceedings of the 2nd Annual Meeting of the NorthEastern Evolutionary Psychology Society. Journal of Social, Evolutionary, and Cultural Psychology, 2(4),169-191.
Frost, P. (2006). European hair and eye color - A case of frequency-dependent sexual selection? Evolution and Human Behavior, 27, 85-103.
Frost, P. (1994). Geographic distribution of human skin colour: A selective compromise between natural selection and sexual selection? Human Evolution, 9, 141-153.
Keeler, C.E. (1947). Coat color, physique, and temperament. Materials for the Synthesis of Hereditary Behavior Trends in the Lower Mammals and Man, The Journal of Heredity, 38, 271-277.
Mogil, J.S., S.G. Wilson, E.J. Chesler, A.L. Rankin, K.V. S. Nemmani, W.R. Lariviere, M.K. Groce, M.R. Wallace, L. Kaplan, R. Staud, T.J. Ness, T.L. Glover, M. Stankova, A. Mayorov, V.J. Hruby, J.E. Grisel, & R.B. Fillingim. (2003). The melanocortin-1 receptor gene mediates female-specific mechanisms of analgesia in mice and humans, PNAS, 100, 4867–4872.
Shekar, S.N., D.L. Duffy, T. Frudakis, G.W. Montgomery, M.R. James, R.A. Sturm, & N.G. Martin. (2008). Spectrophotometric methods for quantifying pigmentation in human hair—Influence of MC1R genotype and environment. Photochemistry and Photobiology, 84, 719–726.
Thelen, T.H. (1983). Minority type human mate preference. Social Biology, 30, 162-180.
Wikipedia. Red hair
http://en.wikipedia.org/wiki/Red_hair
