This essay addresses the argument that rape may be an adaptation as an evolutionary survival strategy, and the counterargument. It presents the physiological and statistical basis of rape from an evolutionary biology perspective and explores the implications of sexual violence in relation to reproductive success.
Professor Daeik Jang begins his discussion of whether rape is an adaptation in his book Darwin’s Table. This is a topic that Thornhill sparked with his book The Natural History of Rape, in which he makes the novel argument that rape is not just an act of violence or a culturally learned behavior, but a phenomenon that can be explained in terms of evolutionary biology. Those who agree that rape is an adaptation view it as an extreme sexual behavior designed to increase male reproductive success and is based on the instinctual motivations of sexual behavior. Opponents argue that there is insufficient statistical data to support this claim, and that rape is simply a byproduct of excessive sexual desire.
We’ll examine the opposition’s arguments against the claim that rape is an adaptation, and provide evidence to support that it is.
The opposition mainly points out errors in the proponents’ interpretation of statistics. For example, Thornhill uses the fact that women of childbearing age are more likely to be raped than women of non-childbearing age to prove that rape is a behavior aimed at reproductive success. However, University of Chicago professor Coyne argues that this data is misleading. He points out that about 29% of all rape victims are children under the age of 11, and many rapes occurred in victims who were unable to reproduce. In about 20% of cases, there was no vaginal penetration, and in about half, there was no ejaculation, so Thornhill’s argument is not statistically supported.
The opposition also cites examples of same-sex rape, incest, and rape against children, and argues that the proponents’ logic cannot account for these cases. Rape is not a result of biological adaptation because it is difficult to explain rape in terms of evolutionary adaptation when the target is incapable of reproduction.
As Coyne points out, it’s clear that Thornhill misinterpreted the statistics. It’s also unreasonable to assume that rapists consciously target women of childbearing age. Conscious thought plays a role in a rapist’s choice of victim, so it’s not enough to argue that unconscious triggers cause rape.
But even if Thornhill’s thesis is flawed, there is still plenty of evidence to support the idea that rape is an adaptation, including the fact that the pregnancy rate from rape is higher than the rate from voluntary sex. A 1996 study by the National Crime Victims Center, led by obstetrician-gynecologist Melissa Holmes, found that approximately 32,101 women in the United States become pregnant as a result of rape each year, or 5% of all victims. In addition, data examined by Courtsell and his colleagues at St. Lawrence University found that about 6.4% of self-reported rape victims became pregnant. This is more than double the rate of pregnancy from consensual sex, suggesting that rape may be a behavior aimed at reproductive success.
Evolutionary psychologist Gordon Gallup explains this difference through a physiological mechanism. He argues that rapists’ semen contains high levels of hormones that trigger a woman’s ovulation, which can lead to a forced pregnancy. In fact, in the animal kingdom, male semen has been observed to induce ovulation in females in some species. According to Gallup, these physiological responses are outside of conscious control, supporting the idea that rape is an unconscious manifestation of the desire to reproduce.
From an evolutionary biology perspective, sexual behavior is part of survival and reproductive strategies in many species. For example, primates such as chimpanzees often acquire sexual status based on social hierarchy, or reproductive opportunities through competition. Some males use coercive methods to mate with females, which can be interpreted as increasing their reproductive success. Human sexual behavior can also be interpreted in this evolutionary context, and it is possible that rape has evolved as one of these reproductive strategies. From this perspective, there is room for rape to be understood as an evolutionary adaptation rather than simply an act of violence.
The idea that rape is an unconscious expression of the desire to reproduce also explains the cases of non-reproductive rape cited by opponents. Evolutionarily and biologically, sexual desire is rooted in the need to reproduce, and it’s impossible to separate the two. As humans have evolved, the desire to reproduce has evolved into sexual behaviors that are directly linked to physical pleasure, which translates into behaviors that can potentially lead to reproduction. Therefore, rape, which seems to be unrelated to reproduction, can be explained as the release of sexual desire associated with the desire to reproduce.
The discussion of whether rape is an adaptation needs to move away from an ethical perspective and look at it as a biological fact. It’s clear that rape is an ethically unacceptable behavior, but that doesn’t mean it’s not an adaptation. From an evolutionary perspective, there’s no denying that rape can be an adaptation.
