A Natural History of Rape: Biological Bases of Sexual Coercion

In this controversial book, Randy Thornhill and Craig Palmer use evolutionary biology to explain the causes of rape and to recommend new approaches to its prevention. According to Thornhill and Palmer, evolved adaptation of some sort gives rise to rape; the main evolutionary question is whether rape is an adaptation itself or a by-product of other adaptations. Thornhill and Palmer address, and claim to demolish scientifically, many myths about rape bred by social science theory over the past 25 years. The popular contention that rapists are not motivated by sexual desire is, they argue, scientifically inaccurate. The book also includes a useful summary of evolutionary theory and a comparison of evolutionary biology's and social science's explanations of human behavior.

Evolutionary psychology often stomps where other branches of science fear to tread. Case in point: A Natural History of Rape. Randy Thornhill, a biologist, and Craig T. Palmer, an anthropologist, have attempted to apply evolutionary principles to one of the most disgusting of human behaviors, and the result is a guaranteed storm of media hype and debate. The book's central argument is that rape is a genetically developed strategy sustained over generations of human life because it is a kind of sexual selection--a successful reproductive strategy. This runs directly counter to the prevailing notion--that rape is predominantly about violent power, and only secondarily about sex.

The authors base their argument partly on statistics showing that in the United States, most rape victims are of childbearing age. But disturbingly large numbers of rapes of children, elderly women, and other men are never adequately explained. And the actual reproductive success of rape is not clear. Thornhill and Palmer's biological interpretation is just that--an interpretation, one that won't withstand tough scientific scrutiny. They further claim that the mental trauma of rape is greater for women of childbearing age (especially married women) than it is for elderly women or children. The data supporting these assertions come from a single psychological study, done by Thornhill in the 1970s, that mixes first-person interviews with caretaker's interpretations of children's reactions.

While Thornhill and Palmer claim that they are trying to look objectively at the root causes of rape, they focus almost entirely on data that support their thesis, forcing them to write an evolutionary "just-so" story. The central problem is evident in this quote, from the chapter "The Pain and Anguish of Rape":

We feel that the woman's perspective on rape can be best understood by considering the negative influences of rape on female reproductive success.... It is also highly possible that selection favored the outward manifestations of psychological pain because it communicated the female's strong negative attitude about the rapist to her husband and/or her relatives.

Women are disturbed by rape mostly because they are worried about what their husbands might think? In statements like this, the authors repeatedly discount the psychological aspects of rape, such as fear, humiliation, loss of autonomy, and powerlessness, and focus solely on personal shame.

A Natural History of Rape will no doubt have people talking about rape and its causes, and perhaps thinking about real ways of preventing it. In fact, the authors suggest that all young men be educated frankly about their (theoretical) genetic desire to rape. And it reopens the debate about the role of sex in rape. But without more and better data supporting their conclusions, Thornhill and Palmer are doing the very thing they criticize feminists and social scientists of doing: just talking. --Therese Littleton