In this blog post, we explore whether rape is an evolutionary adaptation for the purpose of breeding a species or a result of simple sexual desire.
Since Darwin published “On the Origin of Species” in 1859 at the age of 50, the concept of evolution through natural selection has been accepted as the orthodoxy in the field of evolutionary biology. The concept of adaptation, which is discussed in the topic, also originates from this natural selection. Natural selection is the concept that individuals that adapt to living conditions in the natural world are selected, while those that do not are eliminated. However, the adaptation here has a slightly different meaning from the commonly known definition of “adapting to or becoming suitable for certain conditions or environments.” In other words, evolutionary adaptation refers to a genetic trait that enables an organism to survive and reproduce better than other organisms by possessing certain characteristics. Take the giraffe as an example. The giraffe with a long neck, which can easily eat the leaves on the higher branches, survives. This long neck trait can be called an evolutionary adaptation. While few biologists argue that natural selection is an important factor in evolution, there is ongoing debate about the extent to which this adaptation can be applied. One of these discussions is whether rape can be understood as an adaptation.
There are two views on this discussion. The first view is the argument of adaptivists that the act of 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 possibility of reproduction manifested as a genetic trait. Another view is the counter-adaptationist claim that rape is the expression of excessive sexual desire as a violent act. They criticize rape as not an adaptation but merely a byproduct of sexual desire or learned cultural behavior, and that the possibility of reproduction is not the only explanation for rape.
First, before evaluating which claim is more valid, it would be helpful to learn about the causes of rape. Basically, the cause of rape can be said to be sexual desire. And sexual desire is basically a desire aimed at preserving the species. Then the fundamental cause of rape can be said to be a desire aimed at preserving the species. This phenomenon can be easily found in the real natural world. The breeding mechanisms of animals can be divided into polygamy, monogamy, and monogamy. In polygamous species, other males, except for the superior males, do not have the opportunity to mate. In the words of Dawkins, the selfish genes in the male’s body want to breed the species. In the case of animals, males give food as gifts or disturb other males through female mimicry to overcome the deprivation of sexual intercourse. From this perspective, rape can be said to be one of the key acts in the reproduction of a species.
The above-mentioned cases of other animals are also well-represented in humans. Although monogamy is the most common in most modern civilized societies, polygamy can be easily found in the history of the past. In such cases, many men would have had difficulty finding a spouse. In this situation, forced sexual activity would have been helpful for the reproduction of the species, and this trait can be called an adaptation. In fact, this type of forced sexual intercourse can be seen in the custom of arranged marriages, and it is said that in Kyrgyzstan, stealing brides is still a common occurrence. This is also more convincing because there was a method of forcibly kidnapping a bride and marrying her in our history. In other words, rape was naturally selected as an act that helps reproduction.
And the claim that rape is simply a byproduct of excessive sexual desire is not valid, given that rape is mainly committed by men against women and that the incidence of rape does not appear to be similar across all classes of society. Sexual desire clearly exists in both men and women. According to statistics, the percentage of rapists is 98% male and 2% female, which is significantly higher in men. Therefore, it can be seen that other mechanisms are at work, not just sexual desire. Looking at the statistics on rapists, 64.5% of them are from the lower class, 34.1% from the middle class, and 1.3% from the upper class. It can be seen that the higher the difficulty in finding a spouse, the higher the incidence of rape. This shows that it is difficult to explain the cause of rape by excessive sexual desire alone.
Here, as a counterargument to the claim that rape is the result of adaptation, there may be an argument that the purpose of rape is not pregnancy but simply sexual desire. This counterargument is that the purpose of rape is not pregnancy, as the victims of rape include not only women of childbearing age but also children, adolescents, and women of childbearing age. In other words, the argument is that rape is simply a byproduct of excessive sexual desire.
To rebut this argument, it can be understood from the perspective of the rapist that the victims of rape include not only women of childbearing age but also children, adolescents, and women of post-childbearing age, because humans do not clearly show whether they are of childbearing age or ovulation externally. In the case of other primates, including chimpanzees, it is easy to distinguish between fertile and infertile individuals during the breeding season, as the external genitalia of the females swell up. However, it is not easy to distinguish between fertile and infertile individuals in humans, so a mechanism to identify fertile females has not been developed. It can be said that rape is committed not only by women of childbearing age but also by a wider range of women to increase the probability of pregnancy. In addition, since the desire for sex itself stems from the desire to reproduce the species, the claim that rape is an adaptation is convincing in that the two propositions of pregnancy and sex cannot be said to be unrelated.
Next, there may be a counterargument that if rape is beneficial for the reproduction of a species, individuals with such traits will make up the majority of the group. If rape is accepted as an adaptation that helps with reproduction, it can be assumed that these individuals will be in a better position to compete and will be the result of natural selection, surviving more and more competitions and eventually making up the majority of the group. However, it is difficult to see an increase in rape in real society, so it is argued that the assumption that rape is beneficial for the reproduction of the species is incorrect.
The following counterarguments can be made to this counterargument. First of all, the decrease in rape can be understood as the disadvantages (legal sanctions) of rape in modern times being greater than its benefits (opportunities for the reproduction of the species). If we think about the distant future, we can expect that the number of traits that do not rape will gradually increase, but this natural selection takes place over several generations, so it is difficult to see it manifesting itself immediately. In fact, if we look at previous societies, we can easily find examples of men who were pushed out of the reproductive competition due to polygamy. In South Korea, polygamy was abolished only after the Enlightenment, and in the United States, polygamy was abolished only 100 years ago. This means that there were a significant number of historically marginalized men, and it is understandable that rape would have served as a means of breeding for these marginalized men.
In the above, we discussed whether rape is adaptive or not. In his book “The Descent of Man,” Darwin explained that the right to choose sex is always given to females. In a broad sense, it can be understood that all the behaviors of men, such as decorating their appearance, developing physical strength, and seeking power, are aimed at seducing females and reproducing the species. However, just as there are males who are born as males but lose the competition, there are cases like this in humans as well. In such cases, humans who could not find a mate would not have been able to reproduce the species in that generation, but the act of rape would have certainly been advantageous for the reproduction of the species. Therefore, the trait of rape can be understood as an adaptation. However, the victims of rape include not only women of childbearing age but also women of non-childbearing age. In this regard, it is expected that the purpose of rape is not to get pregnant but to satisfy sexual desire. However, this objection can be explained as follows: in the case of humans, it is difficult to determine whether a woman is of childbearing age or ovulation because it is not clearly indicated, so there is no need to create a mechanism to identify women of childbearing age. This means that rape can occur in a wider range of women to increase the probability of pregnancy. Ultimately, rape is a male’s struggle to increase the chances of conception even slightly, and this can be understood as an adaptation for the purpose of breeding.
