This article addresses the academic debate over whether rape is a biological adaptation or a byproduct. Adaptationists, as represented in Thornhill’s Natural History of Rape, argue that rape is a strategy for reproductive success, based on the fact that women of childbearing age are primarily victims of rape. Opponents counter that statistics and various examples of rape, such as child sexual assault, do not support this. The argument is that rape is a complex behavior that involves biological, psychological, and social factors and should be viewed as a byproduct, not an adaptation.
As evolutionary theory has evolved, there have been various discussions about what might be subject to natural selection. One controversial topic is the question “Is rape an adaptation?” This question was first addressed in Thornhill’s Natural History of Rape, and is significant for its biological approach to rape. However, there is disagreement among scholars about whether rape is actually an adaptation. Thornhill’s book tackles the topic in the form of a debate between the pro and con sides. Richard Dawkins’ team argues for the “rape is an adaptation” position, while Stephen Jay Gould’s team argues for the “rape is not an adaptation” position.
First, let’s look at the evidence for the rape-is-an-adaptation argument, which is presented in Thornhill’s Natural History of Rape. The first is that the majority of rape victims are women of childbearing age. The argument is that men who are unable to mate may turn to rape as a last resort to increase their reproductive success. The second rationale is that women of childbearing age are more likely to be raped than women of non-childbearing age. Finally, Thornhill argues that rape in human males may be a product of adaptation, citing the presence of certain organs in some animal males that facilitate rape.
On the other hand, the opposition’s position is: first, the statistics Thornhill presents on the age of victims are insufficient to support the claim that rape is an adaptation: statistical analysis shows that there is no significant difference between non-childbearing women over the age of 44 and childbearing women between the ages of 12 and 44 in terms of trauma and violence. Second, there is the issue of child sexual assault. Thornhill argues that child victimization is less than that of women of childbearing age, but the comparison is inappropriate in that children are inarticulate, making it difficult to make accurate statements. This argument is also unconvincing in that children who are unable to conceive account for 30% of all rape victims. Third, the diversity of rape cases – rape between men, incestuous rape, and rape of children – makes it difficult to support the explanation that rape is a result of adaptation.
Taken together, these arguments lead me to take a position against the “rape is adaptation” thesis. To understand rape, we need to consider the actual act of rape. Rape can be viewed as an act that arises from a conflict between sexual desire and value judgments (ethics and morality): when sexual desire is stronger, rape is more likely to occur, which is the result of a conflict between “the strength of biological sexual desire” and “sensitivity to ethical standards”.
What is important for this thesis is to remove ethical concerns and view rape in terms of adaptation. However, this implies that even if rape is biologically adaptive, it is still ethically evil. Thus, rape is not solely a biological phenomenon, but ethical factors also influence its motivation. This makes it difficult to characterize rape as a purely biological adaptation.
Next, let’s look at “Is rape an adaptation?” In your book, you discuss adaptation and byproducts, and you use the analogy of a spandrel to illustrate this. I don’t think everything can be an adaptation, there are bound to be many byproducts, and I think rape is one of those byproducts. For example, if the digestive system is the result of an adaptation during evolution, then diseases of the digestive system, such as gastritis or enteritis, cannot be seen as adaptations. Although individuals with these diseases are unlikely to survive natural selection, they can be seen as byproducts of evolutionary change for the better. Therefore, byproducts can exist, and rape can be seen as a byproduct.
Those who argue that rape is not a byproduct but an adaptation may point to the very short period of time in human history when rape has been a problem. According to evolutionary theory, a long period of time is required for a trait to be naturally selected for, but human history is relatively short, so it is difficult for rape to have been subject to natural selection due to its ethical problems. However, this argument is not sufficient: humans have lived in groups for a long time, and have developed organized social structures along with the use of tools. This is long enough for evolution to have occurred, and the perception that rape is ethically problematic has also been present in human society for a long time, so it is difficult to argue that ethical factors have not influenced rape.
Some argue that rape is an adaptation using animal anatomy as an example: some animal males, such as the underdog, have organs that facilitate rape, and human semen composition can change to make it more suitable for conception in rape situations. However, this is hardly an adaptation specific to rape. Semen composition can be altered by psychological factors, which have nothing to do with the act of rape itself. Also, as mentioned earlier, social comparisons in animals support the argument that rape is ethically problematic, not natural selection.
Another argument against the claim that rape is a byproduct is the use of socially visible statistics. Thornhill uses statistics from the natural history of rape to argue that rape is an adaptation. However, these statistics are insufficient to determine whether rape is a biological adaptation, as the act of rape is intertwined with ethical and moral factors in addition to biological ones. The statistics do not control for differences in the perpetrator’s ethics and sexuality, so it is unreasonable to conclude that rape is a biological adaptation based on them.
Furthermore, the opposing side sees a logical leap in the argument that rape is an adaptation because it is effective for reproduction. According to this argument, any behavior can be viewed as an adaptation if it is effective for reproduction, which means that behaviors such as stealing or killing can be adaptations if they are beneficial for survival and reproduction. However, it is a logical fallacy to argue that behaviors are adaptations because the targets of natural selection are traits, and behaviors occur as a byproduct of traits.
The debate over whether rape is an adaptation or a byproduct is significant because it approaches rape from a biological perspective. However, rape is a complex behavior that involves not only biological traits, but also social and ethical factors, making it difficult to see it as an object of natural selection. The statistical evidence for rape as an adaptation is also lacking due to the uncontrolled interaction between the factors, and it is a logical leap to consider the behavior as an adaptation because it is advantageous for survival. In conclusion, rape is a byproduct, not a trait, of natural selection from an evolutionary perspective.
