Has evolutionary history led us to today’s rapes?
My mother always said that the world has come to its end. In a way, she was right. Not literally, of course. The earth will not stop turning around the sun. I’m talking about our species here. We think we are good in what we do, and, again, in a way, that is true. In only a few thousand years we have developed the skills to look through microscopes and see microscopic cells floating around in media we made ourselves, to manipulate genetic content in order to obtain the ideal crop, and to have a man walking on the moon. These unique and extraordinary skills, however, do not mean that we are no longer part of nature, although we often want to believe that.
We do not understand ourselves yet
Isn’t it true that we have evolved too swiftly over the past few hundreds of years? It is true, but again, in a particular way. We live in an artificial habitat that we have constructed ourselves. Shelter and protection are no longer brought by natural caves or thorn branches, as in the old days of early hominids. We live in concrete, glass and metal constructed houses, apartments and skyscrapers, far away from the forests we grew up in -- figuratively, that is. The wild environment in which we belong according to our genetic makeup is gone. Both our environment and culture have altered in such a substantial way that our behavior is no longer appropriate. Perhaps even worse: we do not know why we are behaving in particular ways, as Dr. Edward O. Wilson, professor emeritus at Harvard University, remarked in his famous The Diversity of Life (1992): “We do not understand ourselves yet and descend farther from heaven’s air if we forget how much the natural world means to us.” Saying that, Wilson was referring to what we often call the sixth extinction crisis, although we can also use this quote in a behavioral point of view. Let me give you an example of how our naturally selected behavior has extremely gone awry.
Burundian women fleeing civil war in their own country face widespread rape and violent abuse in refugee camps in western Tanzania, Human Rights Watch said in a report [...].
When Burundi women fled the internal conflict there, they expected to find safety and protection in the refugee camps, the report's author Chirumbidzo Mabuwa said.
Instead they simply escaped one type of violence in Burundi to face other forms of abuse in the refugee camps in Tanzania. [...]
Refugee women are particularly vulnerable to rape, sexual assault and other forms of sexual violence, the report said, often when performing routine tasks like gathering firewood, collecting vegetables or looking for work in Tanzanian villages.
This is just a story I picked from the Internet (CNN, Sep 25 2000). Many other examples from all over the world can fill up hundreds, even thousands of blogs like this one. Now, do we have an explanation for this behavior? We do, in fact, and I can simply repeat that both our environment and culture have altered in such a substantial way that our behavior is no longer appropriate. What has gone wrong? To answer this question, we need to dig up some evolutionary history of our very own species. Let’s go back in time.
From hunter-gatherers to early sedentary economy
Chimpanzees and bonobos are our closest living relatives. There are no arguments available to say that Homo has had other sexual behaviors than theirs. So if male philopatry is the rule for a small set of primate species, including chimpanzees and bonobos, among others (spider monkeys, muriquis, and wooly spider monkeys), it will also have been the rule for the earliest nomadic human representatives. In a male philopatric system the males remain in their natal group and form close ties, whereas the females transferring from their natal group at sexual maturity. The latter phenomenon is called female exogamy.
What was a man to do to have sex in prehistoric times? He needed to show off his good characteristics. The ladies at that time liked a strong, healthy man who was preferentially highly trustworthy as well as altruistic. He had to protect his kids – his genes, his evolutionary success – every way he could, if needed by throwing his own life into battle. If women could see what efforts he would make to protect them, their kids, and even others in the community, they would all fall for him. Selection would choose and favor unselfish and protective men.
Living together with all these other familiar men – father, brothers, nephews, uncles, and so on – he did not have to protect his clan on his own. So that is what they did: fighting together, protecting their community together, and even strengthening their bonds-of-childhood.
I don't know whether or not it was a happy time but at least men were social beings, taking care of everybody in a selfless way. In the male philopatric system, all men were relatives; they shared genes. If a member of the clan was not a relative, then it was a woman, and what would a healthy man want to do with an unrelated woman in order to boost his fitness? Precisely, he would try to impress her, show off, and convince her of his protective skills and reliability. Only then, he would have the chance to get to know her more closely.
The rapid and large-scale domestication of animals (livestock), but especially of plants (agriculture), as early as 10,000 to 7,000 years ago, both triggered by climate amelioration in the early Holocene, has had far-reaching consequences upon human existence: we started a sedentary lifestyle. For the first time in our history we were exposed to possession, craftsmen, power, excess of food, money, and – as you could have guessed – the opposite as well: poverty and scarcities. Unlike during our nomadic existence before, where the number of births and deaths remained in almost perfect balance, the population density rose and rose.
In today’s society – I’d better not refer to up-to-date, exploding, population densities – successful men will gain high status, power, and ... women, if desired even multiple women. Their reproductive success is indisputable. On the other side are the unemployed and unmarried men, often-young males facing complete reproductive failure. Their fitness is nil, and they are not exactly keen on changing that, on the contrary: it’s been proven that particularly young men will encounter many more accidents and fatalities in motor vehicles than women do. They seem to be especially good at this in the company of other young men (social facilitation).
I hear you, what has all this to do with our early sedentary humans? Well, this is where our story takes a turn and will eventually lead to the gang rape and murder of the 23-year-old woman in New Delhi, India a few weeks ago.
Young men in a settlement with food shortages would feel the pressure upon their shoulders. Feeling useless and marginalized, some like-minded guys got together, formed a gang and started looting others’ possessions, not in the same settlement, of course. As they were outside of the social controlled society they had always known, they were given new opportunities: it would no longer be of any importance whether they did something good or bad. Who would even care? They were free now and all that mattered was their reproductive success. So why not rape women from other, neighboring or even further, settlements? The set rules of the sexual game – be protective, be trustworthy, don’t be aggressive, don’t be jealous – would forever change.
From that moment on, men showed aggressive behavior, which seemed to result in greater reproductive success than a social, altruistic behavior. Woman of a foreign settlement had become bait. A rape would result in a child, carrying the father’s genes. Mission accomplished, without having lost any energy in showing off and being protective. Selection will favor male aggression from now on. This is how evolution by natural selection works (from E.O. Wilson's The Diversity of Life):
New phenotypes, or the altered traits in anatomy, physiology, or behavior, usually have some effect on survival and reproduction. If the effect is favorable, if they confer higher rates of survival and reproduction, the mutant genes prescribing them proceed to spread through the population. If the effect is unfavorable, the prescribing genes decline and may disappear altogether.
Based upon this very condensed version of our natural history, I would like to draw your attention to these following conclusions. First, the Agrarian (Neolithic) Revolution has caused male aggression (to become a widespread characteristic); hence this feature is not inherent to Homo sapiens. Second, whenever social control mechanisms fail we – even if we are rational and intelligent – discriminate, rape, torture, or loot.
The gang rape of last year’s December 16 shocked the world. Many of us were plunged into thought wondering how this world had gotten this far, as my mother did once, a long time ago now.
Great waves of solidarity, admonishing all forms of sexual violence, were initiated all over the globe. Yet, we all belong to that same species, which in absence of social control violates the law with crimes of all sort.
Just this week Time World published the following poem of Indian Anubha Sharma:
Let there be no mothers
Let there be no wives
Let there be no daughters
And there will be no crimes
Maybe this is true. This, however, is not our world. And how would we even be able to fulfill our most existent task, that is to gain reproductive success, if we locked up all women?
Author's comment: I'm trying to understand how human's behavior can be traced back to evolutionary history. Only by attempting to understand humans in their wild environment, one can evaluate how our current behavior differs from our original nature, as I stressed above by citing E.O. Wilson. This post is based on previous academic coursework and scientific papers. It is not my intention to condone rape cases or, even worse, imply rape is a "normal" action because of our evolution. God no.
References and further reading
Bhowmick N 2013. The Real Shame: India’s Patriarchy Roars Back After Delhi Gang Rape. Time World, January 18.
Gupta AK 2004. Origin of agriculture and domestication of plants and animals linked to early Holocene climate amelioration. Current Science 87 (1): 54-59.
Haak W, Forster P, Bramanti B, Matsumura S, Brandt G, Tänzer M, Villems R, Renfrew C, Gronenborn D, Alt KW & J Burger 2005. Ancient DNA from the first European farmers in 7500-year-old Neolithic sites. Science 310 (5750): 1016-1018.
Kappeler PM, Silk JB, Burkart JM & van Schaik CP 2010. Primate behavior and human universals: exploring the gap. In: Kappeler PM & JB Silk (eds) Mind the Gap. Tracing the Origins of Human Universals. Springer, Heidelberg, Germany: 3-15.
Lovejoy CO 2009. Reexamining Human Origins in Light of Ardipithecus ramidus. Science 326: 74.
Silk JB & Boyd R 2010. From grooming to giving blood: the origins of human altruism. In: Kappeler PM & JB Silk (eds) Mind the gap. Tracing the origins of human universals. Springer, Heidelberg, Germany: 223-244.
Thornhille R & CT Palmer 2000. The natural history of rape: biological bases of sexual coercion. MIT Press, Cambridge, Massachusetts.
Wilson M & M Daly 1985. Competitiveness, risk-taking and violence: the young male syndrome. Ethology and Sociobiology 6: 59-73.