This article addresses the question of whether rape is an advantageous adaptation for reproduction or simply a consequence of excessive sexual desire, using Darwin’s theory of natural selection to explore the issue from a variety of biological and social perspectives.
Since Darwin published On the Origin of Species in 1859, at the age of 50, the concept of evolution by natural selection has been accepted as orthodoxy in the field of evolutionary biology. The concept of adaptation in this topic also stems from this natural selection. Natural selection is the idea that individuals that are adapted to the living conditions of the natural world are selected, while those that are not are culled. However, adaptation has a slightly different meaning than the more common definition of adaptation, which is “to respond to or become suitable for certain conditions or circumstances.” Evolutionary adaptation refers to genetic traits that allow an organism to survive and reproduce better than other organisms by having certain characteristics. For example, in the case of giraffes, short-necked giraffes and long-necked giraffes survive because the long-necked giraffes are able to eat leaves from higher up in the tree. This long neck trait is an evolutionary adaptation. Few biologists would disagree that adaptation by natural selection is an important component of evolution, but there are ongoing debates about the extent to which it can be applied. One of these debates is whether rape can be understood as an adaptation.
There are two schools of thought in this debate. The first is the adaptationist argument that rape can be seen as an adaptation. They argue that the act of rape allowed men who had difficulty finding a mate to spread their genes through rape, and that this act of increasing the likelihood of reproduction was expressed as a genetic trait. The other view is that rape is an anti-adaptationist argument that excessive sexual desire is expressed through the violent act of rape. They argue that rape is a byproduct of sexual desire or learned cultural behavior, not adaptation, and that reproductive potential alone does not explain all of the causes of rape.
Before we can assess which argument is more valid, it’s helpful to understand the causes of rape. Basically, we can say that rape is driven by sexual desire. And since sexual desire is basically a desire to preserve the species, the underlying cause of rape is the desire to preserve the species. This phenomenon can be seen in the natural world. Animal reproduction mechanisms can be categorized into polygamy, polyandry, and monogamy. In polygamous races, all but the best males don’t have the opportunity to have sex. According to Dawkins, the selfish genes in males want to reproduce the species. In animal examples, to overcome this lack of access to sexual intercourse, males will give food as gifts or cross-dress to distract other males from mating with females. From this perspective, rape is one of the key behaviors in reproducing a species.
The examples of the other animals mentioned above are also well represented in humans. Although monogamy is the most common in most modern civilized societies, polygamy can be found throughout history. In these cases, many men would have had difficulty finding a mate. In this situation, forced sexual behavior would have helped the species reproduce, and we can call this trait an adaptation. In fact, we can see this kind of forced sex in bossam marriages, where it is still practiced in Kyrgyzstan, where bride stealing is still a common practice. This is further supported by the fact that bride-stealing has been practiced throughout our own history, meaning that rape has been naturally selected to aid reproduction.
And the argument that the act of rape is simply a byproduct of excessive sexuality lacks validity given that rape is primarily perpetrated by men on women, and that the incidence of rape is not similar across all strata of society. Sexual desire clearly exists in both men and women. Statistics show that rape perpetrators are disproportionately male, with 98% male and 2% female, so there are other mechanisms at play than just sex drive. The statistics also show that rape perpetrators are distributed according to living standards, with 64.5% in the lower class, 34.1% in the middle class, and 1.3% in the upper class, and that the more difficult it is to find a spouse in a conventional way, the higher the incidence of rape. This shows that it is difficult to explain rape by excessive sexual desire alone.
As a rebuttal to the argument that rape is an adaptation, it could be argued that the goal of rape is not pregnancy, but simply sexual desire. This rebuttal argues that the goal of rape is not pregnancy, given that the victims of rape include not only women of childbearing age, but also children, adolescents, and women of post-childbearing age. In other words, it argues that rape is simply a byproduct of excessive sexual desire.
To rebut this argument, the fact that the victims of rape include not only women of childbearing age, but also children, adolescents, and women of post-childbearing age can be explained by the fact that, from the perpetrator’s perspective, humans do not have external signs of fertility or ovulation. While chimpanzees and other primates can easily distinguish between fertile and infertile individuals, for example, by the large swelling of a female’s external genitalia during breeding season, humans have not developed a mechanism to identify fertile women. In order to increase the chances of conception, rape is practiced on a wider range of women, not just those of childbearing age. The argument that rape is an adaptation is also supported by the fact that the desire for sex is itself driven by the desire to reproduce, so the two propositions, pregnancy and sex, are not unrelated.
Next, it could be argued that if rape is beneficial to reproduction, then people with this trait would be the majority of the population. If rape is accepted as an adaptation that helps reproduction, then we can assume that they would be in a better position to compete, which would be the result of natural selection, and they would survive more and more survival competitions, eventually becoming the majority of the herd. However, it is difficult to see an increase in rape in the real world, so it is argued that the assumption that rape is beneficial for reproduction is incorrect.
There are several possible rebuttals to this argument. First, the decline in rape can be understood as a result of the fact that in modern times, the disadvantages of rape (legal sanctions) have outweighed the benefits (reproductive opportunities). If we were to look to the distant future, we might expect to see an increase in the non-rape trait, but this natural selection takes many generations to occur, so it is unlikely that it will manifest itself immediately. In fact, if we look at previous societies, we can easily find examples of men being pushed out of the reproductive race by polygamy. In South Korea, polygamy was not abolished until after the flowering period, and in the United States, it was only 100 years ago that polygamy was abolished. This means that the number of historically marginalized men is not small, and it is understandable that rape would have served as a means of reproduction for these marginalized men.
Above, we discussed whether rape is an adaptation or not. In The Origin of Man, Darwin explained that the choice of sex has always been given to females. The things that men do to enhance their appearance, increase their physical strength, and seek power can all be understood in the grand scheme of things as a way to attract females and reproduce the species. However, just as there are males who are born male but lose out in competition, the same is true for humans. In this case, a human who did not find multiple mates would not have been able to reproduce in that generation, but the act of rape would have been advantageous for reproduction. Therefore, we can understand the trait of rape as an adaptation. However, the victims of rape include not only women of childbearing age, but also women of non-childbearing age. In this respect, one might expect an objection that the purpose of rape is not procreation, but sexuality. However, this objection can be explained by the fact that in humans, there is no clear indication of fertile or ovulatory periods, making it difficult to determine when a woman is of childbearing age, so there was no need to develop a mechanism to identify women of childbearing age. In other words, rape may have been practiced on a wider range of women to increase the chances of conception. After all, rape is a male’s attempt to improve his chances of conception, which can be understood as an adaptation for reproduction.
