In this blog post, based on the arguments presented in the essay “Rape Is Not an Adaptation,” I will summarize the pros and cons of whether rape can be viewed as an evolutionary adaptation and introduce the author’s arguments and conclusions.
Background of the Debate
In an era when there were no reliable theories other than creationism—which held that life on Earth was created by God—the British naturalist Charles Darwin proposed a new hypothesis called “evolutionary theory.” He believed that evolution occurs when only individuals possessing traits advantageous for survival in a given environment are “naturally selected.” In other words, individuals with traits that “adapt” to the environment spread their genes, and this is the order of nature.
Amid this trend, Randy Sonhill and Craig Palmer argued that rape is also an adaptation, sparking the debate: “Is rape an adaptation?” As with most debates, the arguments for and against are sharply divided. Regardless of social and ethical condemnation of rape, the question of whether it constitutes an adaptation from an evolutionary biological perspective influences preventive measures and approaches. The reference book *Darwin’s Table* also provides a clear summary of both sides of this issue.
Arguments for and against, and the author’s position
Proponents argue that rape is part of an adaptation designed to facilitate reproduction. Citing the fact that the majority of rape victims are young, fertile women, they view rape as an adaptive behavior advantageous for survival by increasing the reproduction rate, and they point to the fact that certain biological structures are conducive to rape as evidence of an adaptation selected by natural selection.
Opponents refute the proponents’ arguments. They argue that the significant proportion of non-reproductive-age women among victims and the fact that 30% of victims are children incapable of pregnancy demonstrate that rape is not the result of an adaptation for reproduction. They also cite the “spandrel” analogy—which suggests that while certain traits may appear to be adaptations, they are actually the byproducts of other traits—to argue that rape cannot be viewed as an adaptation.
The author cautiously argues that, based on the definition of “adaptation” in a purely academic sense, rape is not an adaptation.
According to Theodosius Dobzhansky, the definition of adaptation is as follows:
“An adaptation is a process by which an organism changes to gain an advantage in its environment, and at the same time, it is a characteristic of the expression of genetic traits that has evolved in a direction favorable to the organism’s survival and reproduction.”
Based on this definition, we can examine whether rape is an adaptation. My judgment is that it is not. The basis for this is that humans have lived in groups organized at the tribal or ethnic level, and within such group settings, norms and institutions governing relationships among members naturally developed. It is difficult to view rape as advantageous for reproduction within the habitat of group life.
It is difficult to find records of a tribe becoming extinct because rape was absent, and records of a tribe prospering because rape was permitted are also rare. Therefore, I believe the claim that rape is advantageous in a biological habitat lacks evidence and is also logically unconvincing.
A counterargument may arise here: since humans have only been living in groups for a short period compared to the entire history of humanity, behaviors such as rape may have evolved long ago. While humans have existed for several million years, group living became established relatively recently (though the exact date is unclear, it is generally considered to be around 40,000 years ago during the Paleolithic era).
The author’s rebuttal is as follows. While it may take over a million years for physical structures to adapt and evolve, adaptations in behavioral patterns or cognitive aspects can change much more rapidly. For example, the rapid development of civilization over the past few hundred years has significantly altered human behavior and cognition. In other words, during the tens of thousands of years that civilization has existed, rape would have been sufficiently suppressed, which likely prevented it from being selected for by natural selection as advantageous for reproduction.
Furthermore, the author views rape not as an instinctive act but as a cognitive one. Instincts are abilities possessed even before birth, but it is doubtful that humans are born with the innate ability to commit rape. Humans are exposed to violent acts and various sexual elements during their upbringing, and they form the concept of rape by cognitively linking these elements. Since this process of association is cognitive, it is difficult to view rape as an instinct.
In summary, the author’s argument is as follows: “Rape is a cognitive act that has been suppressed for tens of thousands of years under civilization and, therefore, likely did not contribute favorably to reproduction.” This argument is open to additional feedback through criticism.
Additionally, I examined whether there is statistical or documentary evidence to support the claim that rape is an “adaptation.” Since the Bronze Age, rape has been institutionally prohibited in our history, and globally, it has been a legally prohibited act. It is difficult to judge regarding earlier eras when writing systems had not yet developed, as no records remain; however, given the lack of records and statistics, there is almost no evidence to confirm whether rape is a behavior that is genetically advantageous for reproduction.
Currently, rape is not a common behavior, nor is it widespread. If rape were the result of adaptation, it would occur more frequently than it does today—and more men would feel the urge to rape—even in the presence of social restraints. Considering the current state of affairs and the definition of adaptation, it is unreasonable to conclude that rape is an adaptation.
In conclusion, based on Dobzhansky’s definition of adaptation and social and historical evidence, I conclude that rape is not an adaptation. It is reasonable to view rape as a complex result of cognitive and social factors combined with social constraints. I conclude this article by once again emphasizing that the claim that rape is an evolutionary adaptation lacks statistical and historical evidence.
