In January of this year, Randy Thornhill and Craig T. Palmer published "Why Men Rape," in The Sciences, a journal of the New York Academy of Sciences. The article was a precis of their book The Natural History of Rape: Biological Bases of Sexual Coercion. A firestorm of comment followed, as was the intent of the authors: Thornhill, a professor of biology at the University of New Mexico, and Palmer, an anthropology instructor at the University of Colorado at Colorado Springs, are proposing a new schema underlying rape.

The conventional wisdom first proposed by Susan Brownmiller in her 1975 book Against Our Will: Men, Women, and Rape, has been that rape is not a sexual act but rather a political act, an act of power, an act that a patriarchal society teaches men to use for the violent subjugation of women. Thornhill and Palmer propose, instead, that rape is an evolutionary adaptation meant to improve the reproductive success of at least some men.

In an interview published in the Daily Lobo, the University of New Mexico student newspaper, Thornhill stated that he and Palmer were aware of the controversy the book would cause, and that they had a plan to get people's attention. Since the purpose of the book was to change the public understanding of rape, and thereby come to better methods of rape prevention, they felt it appropriate to manipulate the media to increase readership of the book.

Thornhill stated that over the past several decades the science of evolutionary biology has become increasingly accepted. This field of biology insists that humankind, in all respects, has been formed by evolution. The wide acceptance of books on evolutionary biology by Richard Dawkins, Daniel Dennett, Steven Pinker, and others led the authors to feel that the time was ripe to base our understanding of rape on evolutionary science rather than on ideology. Their goal was to replace the conventional wisdom, which they feel is based on feminist and political ideologies and creationism, with a scientific understanding rooted in the principles of evolutionary biology. The response to the media blitz that Thornhill and Palmer mounted was predictable: lots of talk-show buzz and lots of reviews from all quarters, with the verdicts tending to depend on whether or not the reviewer's particular ox had been gored.

The book proposes a sea change in our understanding of rape. Thornhill and Palmer mean to overturn what they see as shibboleths held by social scientists and feminists for several decades. Indeed, in his interview with The Daily Lobo, Thornhill said, "We want to change the whole structure of society pertaining to how we deal with rape."

Do the authors prove their hypothesis? The scientific method dictates that a hypothesis is formed based upon consistency of observation and predictions. That hypothesis is then tested against further observation, prediction, and experiment, and modified as such. A single test disproving the theory can result in falsifying the entire hypothesis.

The authors begin on firm Darwinian ground. By 1859, Darwin formalized much of what had long been understood about the difference between males and females: In our lineage females generally have a much larger investment in offspring, both in time and energy, than do males. Females carry and deliver offspring, then feed and nurture the young. The large investment of time and energy required for each offspring means that females have relatively few chances at reproductive success during their lifetime. The male investment of time and energy for one offspring, on the other hand, can be no more than that of insemination. Selection would favor females who were very choosy in their choice of a mate; those females, who select mates that are most genetically fit, and most likely to contribute to the care of offspring, would be expected to be more successful in the reproductive wars. Males, on the other hand, would improve their reproductive success by mating indiscriminately and as often as possible, suggesting that females would withhold sex to further their reproductive success and males would compete for sex to further theirs.

Thornhill and Palmer hypothesize that unfit males, those not chosen in the mating dance, would rape in order to have some chance of producing offspring. Further arguing that rape, when the risk is low, would even increase the reproductive success of more fit males who have done well in the reproductive wars. If evolutionary selection pressure in males favored rape to increase reproductive success, one would expect that there would be a corresponding evolutionary change among females to mitigate that success. For, after all, rape subverts the female strategy of choosing the very best father for her offspring. The authors' hypothesis for this female adaptation involves the psychic pain following rape. This adaptation would help women recover from successful rape and help prevent future rape. To support their hypotheses the authors postulate that since rape occurs as an adaptation in other species, it could equally well occur in humans. Next the authors propose, in effect, that the reproductive success of rapists must exceed that of non-rapist males who also were not chosen in the mating contests. And finally the authors propose that the psychic trauma of rape is greater for reproductive-age women than for women above or below reproductive age.

The data the authors use to support their predictions is thin. A good deal of the data they use precedes the 1996 start date for this book, and no matter how they torture that data, it provides little support for their hypotheses. The operational difficulties of obtaining data to show that the reproductive success of rapists exceeds that of similarly situated non-rapists form a formidable barrier. Moreover, the studies offered by the authors do not surmount that barrier. Quantifying the psychic trauma of women who have suffered rape is another very problematic prospect, and by no means does the data provided here prove that reproductive age women suffer more psychic trauma, nor that that putative trauma is in any way protective.

A significant proportion of this slim volume is devoted to the disparagement of feminists, social scientists, creationists, and all others who have not yet come to the true faith of evolutionary biology. If the authors wish to disparage, that is their privilege, but it does little to advance their cause. Thornhill and Palmer have not disproved the explanation of rape proposed by Brownmiller and those who have followed her, nor have they proved their alternative explanation. The social science theory, so roundly condemned by Thornhill and Palmer, has produced a great deal of good in the societal understanding and treatment of rape. In addition, further studies may well resolve the issue in a manner satisfactory to the authors. Meanwhile we hope this faulty work will affect improved public understanding of rape, better preventive methods, and better treatment for women who suffer this crime.