In this blog post, we will focus on the “rape maladaptation theory” proposed by evolutionary psychology, taking a balanced look at the evidence supporting it and the arguments against it, while examining its validity and limitations.
Introduction
Living organisms undergo a process in which individuals better adapted to the environment survive through competition for survival, while those that are not are eliminated. Darwin’s theory of evolution generalizes this process, presenting natural selection as its core mechanism. “Darwin’s Table” explains: “If individuals within a population differ from one another, and because of those differences, their abilities to respond to the environment vary, and if those differences happen to be passed on to the next generation, then natural selection operates. Evolutionary biologists generally refer to the product of natural selection as an adaptation.” However, there remains significant debate regarding the relative influence of natural selection, the criteria and methods for distinguishing between adaptation and non-adaptation, and whether the human mind and behavior have evolved through natural selection.
The essence of the debate and my position
The argument “Is rape an adaptation?” is broadly divided into two camps. One camp holds that rape is an adaptation, while the other maintains that rape is unrelated to evolution and therefore not an adaptation. Even among those who support the former view, there are two distinct positions: one that views rape as a direct product of evolution and genetics, and another that views it as an indirect product. In a narrow sense, the former can be expressed as “rape is an adaptation,” while the latter can be expressed as “rape is not an adaptation.” I tend to agree more with the position that rape is an indirect product of evolution and genetics.
One argument from the pro-side is Professor Cosmedes’ claim that male rape behavior was directly selected by natural selection over a long evolutionary process, particularly for males who faced difficulties in mating. Professor Finger criticized the purely ideological approach to this topic, arguing that understanding it from an evolutionary biological perspective could lead to more effective methods for preventing rape crimes. Furthermore, Professor Dawkins argued that “the most obvious example of adaptation is the human eye,” developing the thesis that only natural selection can produce such sophisticated traits, while Dennett’s discussion uses the architectural analogy of “spandrels and corbels” to demonstrate that certain traits can be byproducts.
Opponents criticize arguments such as “The Natural History of Rape” for failing to present sufficient evidence. Professor Coine argued that the claim that most rape victims are women of childbearing age is incorrect, citing the lack of difference in rape victimization rates between women of childbearing age and those outside that age range, as well as issues regarding the reliability of statements from child victims. He also pointed out that the logic of using specific bodily organs in insects to conclude that human rape is an adaptation is insufficient. Gould, Rowintun, and others explain the dangers of adaptationist interpretations using the “spandrel” analogy, warning that structural byproducts are sometimes mistakenly interpreted as adaptations.
Taking these discussions into account, I conclude that it is difficult to view rape as a direct adaptation. I will explain the reasons for this in detail below.
Evidence That Rape Is Not an Adaptation
First, for a trait to be recognized as an adaptation, it must aid survival and reproduction as a result of natural selection, and that trait must be genetically transmitted to the next generation, thereby increasing its prevalence within the population. However, no clear link to specific genes determining rape has been presented. If there is no genetic basis, even if reproductive success temporarily increases due to rape at a given point in time, it is unlikely to be genetically fixed in the next generation; therefore, it is difficult to view it as an adaptation resulting from natural selection. While social trends may lead to an increase in rape, this is merely a sociocultural phenomenon distinct from adaptation.
Second, considering the motives and forms of rape, reproduction is often not the direct purpose. The types of rape classified by Nicholas Gross—rage-driven, power-driven, and sadistic—are characterized by aggression aimed at humiliation and inflicting harm, expressions of domination and power, or sexual arousal derived from aggression, respectively. These types demonstrate motives that are unrelated to reproduction or even contrary to it. It is not valid to interpret these acts as reproductive adaptations simply because they involve sexual intercourse.
Third, it is inappropriate to apply examples from insects directly to humans. To view human rape as an adaptation based on the fact that insects like the example cited possess physical structures conducive to rape is a comparison that ignores the complex social and psychological context of humans. This is akin to the absurd oversimplification of claiming, “Since dolphins communicate using ultrasound, humans must do so as well.”
Fourth, even if, as Cosmides argues, males who struggle to mate gained reproductive opportunities through rape, there is no guarantee that the traits possessed by such males would be advantageous in the long term. If their traits are inferior to those of other males, it would be difficult for those genes to increase within the population over the long term. Furthermore, in reality, women would likely form groups to protect themselves upon recognizing danger, and perpetrators would face a high probability of social exclusion or punishment, making it difficult to maintain any reproductive advantage. The social unit referred to here refers to a communal context, such as a village, rather than the modern nation-state.
Finally, the distress and psychological trauma experienced by rape victims can be viewed as part of a universal adaptation for humans to protect themselves from violence. The instinct for self-protection and the resulting emotional responses do not support the claim that rape itself is an adaptation. Such defensive adaptations can reinforce the negative consequences of violent acts, thereby inhibiting the conversion of such behavior into reproductive benefits.
As seen above, the claim that rape is an evolutionary adaptation lacks validity for several reasons, including a lack of genetic evidence, various non-reproductive motives, limitations in interspecies comparisons, long-term selective pressures, and social sanctions. Therefore, I do not view rape as an adaptation.
