The latest evolutionary psychology[1] theory to do the rounds is that blondeness evolved as a selection strategem for women trying to attract scarce mates in the harsh and male-scarce conditions of Ice Age Europe. According to this report in the Times, the theory has been formulated by an anthropologist, Peter Frost. His supporting argument is that blondeness is a signal of high levels of oestrogen. I suppose I should wait for the article which is supposed to come out in Evolution and Human Behaviour, but I can’t resist pointing to an obvious hole and an alternative explanation.
The obvious hole is that blond(e)ness is not a sex-linked characteristic. If light hair colour signals high oestrogen, blond men should have a lot of trouble attracting mates. Tempted as I am by this hypothesis (see photo here), I can’t say I’ve seen any evidence to back it up.
The alternative explanation (not at all novel) is that fair hair arose in conjunction with pale skin, as a straightforward physical adaption to the move away from the tropics – less need for pigment, or maybe more need to absorb vitamin D.