The Red Queen_ Sex and the Evolution of Human Nature - Matt Ridley [139]
Freud and Incest Taboos
Very few men have sex with their sisters. Caligula and Cesare Borgia were notorious because they were (rumoured to be) such exceptions. Even fewer men have sex with their mothers, in spite of what Freud tells us is an intense longing to do so. Sexual abuse by fathers of daughters is far more common. But it is still rare.
Compare two explanations of these facts. First, that people secretly desire incest but are able to overcome these desires with the help of social taboos and rules; second, that people do not find their very close relatives sexually arousing, that the taboo is in the mind. The first explanation is Sigmund Freud’s. He argued that our first and most intense sexual attraction is towards our opposite-sex parents. That is why, he went on to say, all human societies impose on their subjects strict and specific taboos against incest. Since the taboo ‘is not to be found in the psychology of the individual’, there is a ‘necessity for stern prohibitions’. Without those taboos, he implied, we would all be dreadfully inbred and suffer from genetic abnormalities.2
Freud made three unjustified assumptions. First, he equated attraction with sexual attraction. A two-year old girl may love her father, but that does not mean she lusts after him. Second, he assumed without proof that people have incestuous desires. Freudians say that the fact that very few people express these desires is because they have ‘repressed’ them – which makes Freud’s argument irrefutable. Third, he assumed that social rules about cousin marriage were ‘incest taboos’. Until very recently scientists and laymen alike have followed Freud in believing that laws forbidding marriages between cousins are there to prevent incest and inbreeding. They may not be.
Freud’s rival in this field was a man named Edward Westermarck, who suggested in 1891 that men do not mate with their mothers and sisters not because of social rules, but because they are simply not turned on by those they were reared with. Westermarck’s idea was simple. Men and women cannot recognize their relatives as relatives, so they have no way of preventing inbreeding as such (curiously, quail are different: they can recognize their brothers and sisters, even when reared apart). But they can use a simple psychological rule that works ninety-nine times out of a hundred to avert an incestuous match. They can avoid mating with those people whom they knew very well during childhood. Sexual aversion to one’s closest relatives is thus achieved. True, this will not avert marriage between cousins, but then there is nothing much wrong with marriage between cousins: the chance of a recessive deleterious gene emerging from such a match is small and the advantages of genetic alliance to preserve complexes of genes that are adapted to work with each other probably outweigh it (quail prefer to mate with first cousins rather than strangers). Westermarck did not know that, of course, but it strengthens his argument, for it suggests that the only incestuous relations a human being should avoid are the ones between brother and sister or parent and child.3
Westermarck’s theory leads to several