Friday, January 21, 2011

Of Hormones and Ethnic Conflict

In my new book, I pose the following question: "If people are basically selfish and our biological imperative is to survive in order to pass down our genes to future generations, how do we explain the willingness of so many people to die for their country or their clan in a war? Throughout history, hundreds of thousands of men have marched headlong and almost without flinching into enemy spears, arrows, gunfire, and bombs, all the while watching their friends and comrades killed or maimed right beside them...

Mothers who send their sons off to war are also honored. In the United States, women whose sons die in war are hailed as 'Gold Star Mothers'... The idea that maybe one should not always be willing to do that was rarely questioned on a large scale anywhere in the world until wide-scale opposition developed to the Vietnam War in the United States in the mid-1960’s."

I go on to explore a theory which may explain the paradox of humankind's willingness towards self sacrifice and the sacrifice of their own children (for example, honor killings in the Middle East, and female infanticide in China) through an evolutionary biological concept called kin selection: "Darwin actually addressed this issue. At first the characteristic of altruism, the willingness to sacrifice oneself for the seeming good of one’s ethnic or kin group, seemed to him to be at odds with his theory of natural selection.

He then realized that this paradox would disappear if he changed his focus from the individual with a good genetic adaptation to the group to which the individual belonged. A single individual with a genetic mutation that is highly desirable and adaptive may still die before reproducing. If a group such as a family, a herd, or a tribe has many individuals who share the adaptation, then the propagation of that gene becomes far more likely."

This could lead to a situation in which genes that predispose individuals to be willing to sacrifice themselves for the kin group, and which cause the kin group to be willing to sacrifice individuals, would be more likely to survive and be passed down from one generation to the next and therefore selected for.

So a tendency towards self sacrifice for the good of the tribe may be in our genetic loading. A lot of evolutionary biologists do not accept the concept of kin selection primarily because they worry it might be used much like the concept of eugenics was in the last century - as an excuse for killing off the weakest members of society. (Some of today's legislators do not seem to need such an excuse). Nonetheless, the potential misuse of a scientific concept is not proof that the concept is invalid.

Now comes some new data which might lend further creedence to the concept of kin selection: (

Oxytocin is a hormone which does a number of things, such as helping cause the contractions of the uterus which expel a fetus during birth. It is also commonly found in the brain, where it has been found to be central to the process of attachment between a new mother and her new baby. As the New York Times article explains, "This tiny chemical, released from the hypothalamus region of the brain, gives rat mothers the urge to nurse their pups, keeps male prairie voles monogamous and, even more remarkable, makes people trust each other more."


Well, not trust everyone, as it turns out: "The love and trust it promotes are not toward the world in general, just toward a person’s in-group. Oxytocin turns out to be the hormone of the clan, not of universal brotherhood. Psychologists trying to specify its role have now concluded it is the agent of ethnocentrism." In an ingenious series of experiments, Dutch psychologist Dr. Carsten K. W. De Dreu found that Oxytocin may "...create intergroup bias primarily because it motivates in-group favoritism and because it motivates out-group derogation.”

The author of the New York Times article describing the experiments raises another interesting question, and gives Dr. De Dreu’s answer: “Early religions were also involved in establishing group cohesion and penalizing offenders. Could oxytocin be involved in the social aspects of the religious experience?” Dr. De Dreu sees oxytocin’s effects as being very general, and no more likely to be associated with the religious experience than with soccer hooliganism. ‘When people get together with others who share their values, that drives up the level of oxytocin,’ he said.”

Still, I often wonder why so many people are so ready to profess to believe transparently and obviously preposterous religious dogma. Perhaps that is a price they are willing to pay in order to maintain in-group status and group togetherness.


  1. Nobody expects to die, specially young people.
    If humans in the rain forest, WAR with another tribe would be a sign of strength manhood-manliness and most returned alive.
    Why do Rams butt heads? Display of (male) genetic superiority for the females.

  2. I love your blog generally but there have never been mass protests against warmaking until Americans did it in the 1960s? A little broader historical perspective is in order here I think (along with less cultural navel-gazing).

    In addition I think humans like all other organisms are primarily hardwired to promote survival of the *species* rather than individual or tribe alone, it can get confusing because because for many people these categories can get conflated.

    1. Mass protests against warmaking yes. Not so sure about mass rejection of the basic idea dying for your country. If you know of of any examples, please share. Thanks.