The Red Queen_ Sex and the Evolution of Human Nature - Matt Ridley [86]
The study of human beings remained resolutely unreformed by these ideas until a few years ago. Even now, most anthropologists and social scientists are firmly committed to the view that evolution has nothing to tell them. Human bodies are products of natural selection, but human minds and human behaviour are products of ‘culture’, and human culture does not reflect human nature, but the reverse. This restricts social scientists to investigating only differences between cultures and between individuals – and to exaggerating them. Yet to me the most interesting things about human beings are the things they share, not the things that differ between cultures: things like grammatical language, hierarchy, romantic love, sexual jealousy, long-term bonds between the genders (‘marriage’, in a sense). These are trainable instincts peculiar to our species and are just as surely the products of evolution as eyes and thumbs are.2
The Point of Marriage
For a man, women are vehicles that can carry his genes into the next generation. For a woman, men are sources of a vital substance (sperm) that can turn their eggs into embryos. For each gender, the other is a sought-after resource to be exploited. The question is, how? One way to exploit the other gender is to round up as many as possible of them and persuade them to mate with you, then desert them, as bull elephant seals do. The opposite extreme is to find one individual and share all the duties of parenthood equally, as albatrosses do. Every species falls somewhere on that spectrum, with its own characteristic ‘mating system’. Where does humanity fall?
There are five ways to find out. One is to study modern people directly and describe what they do as the human mating system. The answer is usually monogamous marriage. A second way is to look at human history and divine from our past what sexual arrangements are typical of our species. But history teaches a dismal lesson: a common arrangement from our past was that rich and powerful men enslaved concubines in large harems. A third way is to look at people living in simple societies with stone-age technologies, and conjecture that they live much as our ancestors lived ten millennia ago. They tend to fall between the extremes: less polygamous than early civilizations, less monogamous than modern society. The fourth technique is to look at our closest relatives, the apes, and compare our behaviour and anatomy with theirs. The answer that emerges is that our testicles are not large enough for a system of promiscuity like the chimpanzee’s, nor are men’s bodies big enough for a system of harem polygamy like the gorilla’s (there is an iron link between harem polygamy in a species and a large size differential between male and female), nor are we as antisocial and adjusted to fidelity as the monogamous gibbon. We are somewhere in between. The fifth method is to compare mankind with other animals that share our highly social habits: with colonial birds, monkeys and dolphins. As we shall see, the lesson they teach is that we are designed for a system of monogamy plagued by adultery.
It is at least possible to rule out some options. There are characteristically human things we do, like forming lasting bonds between sexual partners, even when polygamous: we are not like sage grouse whose marriages last for minutes. Nor is mankind polyandrous, like the jacana or lily-trotter, a tropical water bird, with big fierce females controlling harems of small, domesticated males. There is only one truly polyandrous society on earth, in Tibet, and it consists of women who marry two or more brothers simultaneously in an attempt to put together a family unit that is economically viable in a harsh land where men herd yaks to support women. The junior brother’s ambition is to leave and obtain his own wife, so polyandry is plainly a second best result for him.3 Nor is mankind, like a robin