randy thornhill & craig palmer a natural history of rape

financial times, 18-19 march 2000

Evolutionary psychology can be a bit like London's Millennium Dome. From the outside it affords an impressive structure, constructed with the help of cutting edge science and technology. But take a peek inside, and you often find an alarming scarcity of real content. So it is with A Natural History of Rape, the latest attempt to apply Darwinian theory to human behaviour.

Biologist Randy Thornhill and anthropologist Craig Palmer believe that human rape 'arises from men's evolved machinery for obtaining a high number of mates in an environment where females choose mates'. At the heart of their argument, as of all evolutionary psychology, is the claim that although we live in a space world, our skulls still house Stone Age minds. Human behaviours, Thornhill and Palmer argue, were originally designed by natural selection to facilitate the reproduction of our genes in our ancestral world. Many behaviours, such as rape, which may have been adaptive then, still haunt us now.

In humans, as in most animals, males and females have developed different reproductive strategies. Men are adapted to mate as frequently and with as many women as possible. Women, on the other hand, are designed to be monogamous and to ensure that their mate stays with them as long as possible. Rape, Thornhill and Palmer argue, is a consequence of these differences. Men rape because it helps spread their genes. The good professors are unsure whether men possess specific brain circuits that tell them to rape, or whether such coercion is the unfortunate outcome of a relentless male desire for casual sex. Either way, they insist that men rape because nature has designed them that way.

If men rape to increase their chance of fatherhood, women are traumatised by rape because it 'lowers their reproductive success'. Rape is painful, apparently, because it 'reduces a woman's ability to choose the timing and circumstances for reproduction, as well as her ability to choose the man who fathers her offspring'. And there I was thinking that the pain of rape had much to do with violence and forcible sex. Thornhill and Palmer, however, will have none of this. Rapists, they argue, do not as a rule use overmuch violence because they don't want to threaten their victim's chance of getting pregnant. Even more contentiously they believe that the trauma of rape decreases with more violent attacks, as injured women are more likely to be believed that they didn't 'ask for it'. The more battered a woman is, the less trauma she endures? It truly is an Alice-Through-The-Looking-Glass world that Thornhill and Palmer inhabit.

Much of the book is a polemic against social science and feminist theories of rape, in particular the belief that rape is a crime of violence, not sex. Social scientists, claim Thornhill and Palmer, are motivated by ideology which has blinded them to Darwinian truth. This rant might have more substance if Thornhill and Palmer's own arguments were not so flimsy and inchoate.

Take, for instance, the claim that natural selection has furnished men with behaviours that makes it easier for them to commit rape. One such possible adaptation is a 'psychological mechanism that help males evaluate the vulnerability of potential rape victims'. Another mechanism may help 'motivate men who lack sexual access to females (or who lack sufficient resources) to rape'. As evidence of the first mechanism, Thornhill and Palmer point to that fact that 'men are most likely to rape when rape's proximate benefits exceed the chances of injury and punishment'. The fact that 'rape is disproportionately committed by males with lower socioeconomic status' is, they suggest, evidence for the second kind of mechanism. The trouble is, you don't need a PhD in evolutionary biology to know that rapists are less likely to strike if they think they will be injured or caught, or that poor, resourceless men are more likely to commit crime, whether burglary or rape. You only insist that such behaviours are natural adaptations if, like Thornhill and Palmer, you are blind enough to believe that all behaviours must be evolved.

Thornhill and Palmer buttress their dubious 'scientific' arguments with even more dubious anecdotes. Men, they claim, get hot under the collar when their partner is raped because 'it reduces his confidence that he sired the mate's previous offspring, and his confidence that he will be the sire of the next offspring if his mate becomes pregnant at the time of the rape.' As evidence they drag up a hoary old tale of an orangutan which had raped a female cook at a primate research centre Indonesia. The woman's husband seemed unconcerned. 'Why should my wife or I be concerned?', he is supposed to have asked. 'It was not a man'. The husband, Thornhill and Palmer tell us, 'reasoned that since the rapist was not human, the rape should not provoke shame or rage.' Neither the husband nor the victim, they suggest, 'seemed to suffer greatly'. It seems astonishing that two learned professors should seriously believe that being sexually attacked by an ape would be of little concern to a woman. It seems even more astonishing that they should attempt to sustain their argument with the kind of salacious anecdote that used to pepper Victorian travellers' accounts of exotic cultures and their sexual mores.

Thornhill and Palmer end the book with as series of proposals to combat rape from an evolutionary viewpoint. Like the rest of their work, these are a mix of the banal, the bizarre and the reactionary. Evolution psychology, they tell us, has come to the conclusion that 'punishment can influence the frequency of rape' and that 'long incarceration' is most effective because it 'removes the offender from everyday male-male status pursuits that young men spend so much time practising.' Now, why didn't I think of that before?

Thornhill and Palmer want all young men to receive 'an evolutionarily informed educational program' which 'gets them to acknowledge the power of their sexual impulses.' Teenagers should be taught 'why they get an erection just by looking at a photo of a naked woman' and why they might 'mistake a woman's friendly comment or her tight blouse as an invitation to have sex.' They must complete such a course before they can get a driving licence. Why evolutionary knowledge about rape should make young men better drivers, Thornhill and Palmer don't explain. But if they truly believe that such an educational programme will curb young men's sexual desires, then they must have long forgotten what it's like to be a teenage boy. The last way to change a teenager's mind is by force-feeding him an adult education programme.

Thornhill and Palmer have advice for women too: don't dress provocatively and don't wear too much make up. A woman's behaviour, they insist, plays an important part in encouraging rape. Thankfully, they accept that the 'seclusion of women' is 'understandably abhorrent to many people', but they worry that 'the common practice of unsupervised dating in isolated environments such as automobiles, often accompanied by alcohol consumption, has placed women in environments conducive to rape to an extent unparalleled in history.' Perhaps, they suggest, young couples should be chaperoned a bit more. Don't wear sexy dresses. Don't get drunk. Don't have a grope in the car. And this from a book that is supposedly ideology-free.

A Natural History of Rape is a deeply dispiriting work that provides little insight into either human psychology or the character of rape. It's a pity because evolutionary biology has much to say about sexual behaviour. But the dogma that human behaviour can only be understood in evolutionary terms is as foolish as ignoring evolutionary theory altogether.