The Red Queen_ Sex and the Evolution of Human Nature - Matt Ridley [79]
Any peahens reading this might begin to recognize their dilemma. For they, too, might be effectively being fooled by the male’s display into buying the second best male. The lek paradox, remember, argues that there is little to choose between males on a lek anyway, because they were all fathered by the same few males in the previous generation. So two theories – truth in advertising and dishonest manipulation – seem to come to opposite conclusions. Truth-in-advertising concludes that females will discover a cheating seducer; dishonest manipulation concludes that males will seduce females against their better judgement.
Why Do Young Women Have Narrow Waists?
Marian Dawkins and Tim Guilford of Oxford have recently suggested a resolution to this conundrum. So long as detecting the dishonesty in the signal is costly to the female, it might not be worth her while to do so. In other words, if she has to risk her life seeking out and comparing many males to ensure that she has chosen the best one, then the marginal advantage she gains by picking the best one is outweighed by the risk she has run: better to let herself be seduced by a good one than to make the best be the enemy of the good. After all, if she cannot easily distinguish the truthful from the dishonest badge of quality, then other females will not either and so her sons will not be punished for any dishonesty they inherit from their father.64
A startling example of this sort of logic comes from a controversial theory about human beings developed a few years ago by Bobbi Low and her colleagues at the University of Michigan. Low was looking to explain why young women have fat on their breasts and buttocks more than on other parts of their bodies. The reason this requires explaining is that young women are different from other human beings in this respect. Older women, young girls and men of all ages put on fat on their torsos and limbs much more evenly. If a woman of twenty or so puts on weight, however, it takes the form largely of fat on the breasts and buttocks; her waist can remain remarkably narrow.
So much is undisputed fact. What follows is entirely conjecture, and it was a conjecture that caused Low a good deal of sometimes vicious (and mostly foolish) criticism when she published the idea in 1987.
Twenty-year-old women are in their breeding prime; therefore the unusual pattern of fat distribution might be expected to be connected with getting a mate or bearing children. Standard explanations concern the bearing of children; for example, fat is inconvenient if it competes for space about the waist with a foetus. Low’s explanation concerns the attraction of mates and takes the form of a Red Queen race between males and females. A man looking for a wife is likely to be descended from men who found two things attractive (among many others): big breasts, for feeding his children, and wide hips for bearing them. Death during infancy from a mother’s milk shortage would have been common before modern affluence – and still is in some parts of the world. Death of the mother and infant from too narrow a birth canal must also have been common. Birth complications are peculiarly frequent in man, for the obvious reason that his head size at birth has been increasing fast in the past five million years. The only way birth canals kept up (before Julius Caesar’s mother was cut open) was through the selective death