David Blumenthal, a good and wise friend who is a Jewish studies professor and a rabbi wrote me recently asking about the former adaptiveness and present maladaptiveness of xenophobia. The operative passage in his letter was, “In the global world, however, survival requires the cooperation of varying and different groups. Humanity, in its groups, cannot survive without the quintessential other. Xenophobia has ceased to be adaptive. So has antisemitism, racism, orientalism, and misogyny.”

I have little trouble agreeing that at some times in the past these behaviors were adaptive for the perpetrators. Generally, xenophobia must have been adaptive in many times and places, as the people over the hill were surely dangerous, not least because your own people posed a threat to them.

The idea that hunter-gatherers (representing the vast majority of human generations) were genocidal and competed as groups remains controversial, but it has gotten a lot of attention lately, especially in the work of Samuel Bowles and Herbert Gintis, whose 2011 book, A Cooperative Species: Human Reciprocity and its Evolution is a major contribution. In it they argue that the exceptional cooperation and altruism seen in our species (compared to monkeys and apes) is the result of group selection during human evolution. Xenophobia made cooperation within groups adaptive for the group, and more cohesive and self-sacrificing groups destroyed enemies bent on selfishness.

Certainly this cannot be ruled out as a deep pattern in human evolution, but some anthropologists think that serious xenophobia and genocide only arose after agriculture or horticulture made it necessary to stand and defend property, and population densities had reached a point where there was no place to go.

But leaving that aside, the real question David raises is whether xenophobia, antisemitism, racism, orientalism, and misogyny are now maladaptive. I’ll set aside the last and try to address it in another posting. But the first question is, have modern genocides been maladaptive for the perpetrators, regardless of how maladaptive we think they have been for the species—not to mention how immoral they are?

These things are difficult to measure. Germans as a group probably did not gain a net benefit from Nazism, because they paid such a high price in the war. Nevertheless, we see a resurgent and successful Germany in which many perpetrators’ descendants are doing well. The same is true of Poles, Ukrainians, and other European peoples, many of whom avidly aided the Nazis. Meanwhile, the Jews in those countries are gone, having been murdered together with their children and grandchildren, most leaving no descendants, and many non-Jews (reparations aside) have long since occupied and benefited from their homes, stores, property, wealth, etc.

General Ratko Mladic and a few others have paid for the much smaller-scale Serbian genocide in Srebenica, but we would have to know more to feel assured that Serbian Christians in that region have not had a net benefit from the elimination of quite a few thousands of Muslim young men and boys. Grim as it is to start counting, an evolutionary theorist would want to know about the reproductive success of the respective populations since the mid-’90s.

In the case of Rwanda, I would be surprised if it could not be shown that there was a net benefit for the Hutu perpetrators at the expense of their 800,000 or so Tutsi victims. Some retaliation occurred but on nothing like the same scale, and the reconciliation process—I’m not saying it’s a bad idea—pretty much guarantees that the perpetrators will never pay remotely the kind of price they imposed on the victims. I don’t know who now benefits from the property of those victims, or for that matter from their permanent removal from competition for resources, but I would not be surprised if some of the perpetrators consider the genocide to have been fairly successful in achieving its primary goals, and I am not sure they would be wrong.

So, alas, I cannot conclude that genocide is any less adaptive for the perpetrators now than it was in most of human history. If we consider the human species as a whole, I certainly think it is maladaptive, but that is not the way we usually calculate reproductive advantage, because it is advantage gained by individuals and, perhaps, groups that has up to now always determined what would evolve. For the forseeable future too, some groups will still seek success at the expense of other groups.

Can we construct a world system in which we impose such costs on perpetrators (as groups, not just their leaders) that they truly hesitate when the next opportunity to benefit from genocide comes up? I don’t think we have done this yet. Many believe that the US and the USSR were each prevented from exterminating the other by the nuclear balance of terror, but this might be hard to do in a multicentric world. Ultimately there would have to be a reliable governing body—something much more effective than the UN—that would ensure a costly and consistent multinational response to perpetrators.

None of these calculations, of course, changes the ethical imperative to oppose and prevent genocide, or for that matter xenophobia, racism, or war. But the above arguments offer some idea of why I am wary of trying to shore up ethical positions by referring to adaptation in the evolutionary sense of the word.

I’ll have something to say about misogyny soon.