Monday, April 4, 2016

Farewell to Henry

Henry Harpending (1944-2016) died this past Sunday. He had a stroke a year ago, and then a second one three weeks ago, but apparently he died of a lung infection. This is one of the risks of getting older: you dodge one bullet only to get hit by another.

The cemeteries are full of people who die before their time, but this is one case where I really wish death had held off a while longer, so that he could see more of the fruits of his labors, particularly in the area of gene-culture coevolution.

No, he wasn’t the only academic to show that culture and genes have coevolved in our species. In fact, the idea probably originated with Claude Lévi-Strauss in the early 1970s:

When cultures specialize, they consolidate and favor other traits, like resistance to cold or heat for societies that have willingly or unwillingly had to adapt to extreme climates, like dispositions to aggressiveness or contemplation, like technical ingenuity, and so on. [...] each culture selects for genetic aptitudes that, via a feedback loop, influence the culture that had initially helped to strengthen them. (Lévi-Strauss, 1971)

This idea of gene-culture coevolution became popular in the 1980s through papers by L.L. Cavalli-Sforza, Robert Boyd, Peter Richerson, and Pierre van den Berghe. It then fell out of fashion because ... well, because. When Paul Ehrlich wrote Human Natures (2000), he returned to the conventional wisdom that cultural evolution had largely replaced genetic evolution in our species. As one became more important, the other became less so.

In 2007, Henry Harpending turned this thinking on its head with a study on changes to the human genome over the past 80,000 years. With four other researchers, he found that these changes actually sped up more than a hundred-fold some 10,000 years ago, when hunting and gathering gave way to farming, which in turn led to population growth and larger, more complex societies. Our ancestors were no longer adapting to relatively static natural environments but rather to faster-changing cultural ones of their own making. They created new ways of life, which in turn influenced who would survive and who wouldn't.

As Henry and his co-authors pointed out, this estimate of a hundred-fold acceleration is actually conservative:

It is sometimes claimed that the pace of human evolution should have slowed as cultural adaptation supplanted genetic adaptation. The high empirical number of recent adaptive variants would seem sufficient to refute this claim. It is important to note that the peak ages of new selected variants in our data do not reflect the highest intensity of selection, but merely our ability to detect selection. Due to the recent acceleration, many more new adaptive mutations should exist than have yet been ascertained, occurring at a faster and faster rate during historic times. (Hawks et al., 2007)

Few ideas belong solely to one person, but Henry deserves credit for perseverance. Most of the others, like L.L. Cavalli-Sforza, eventually found it expedient to focus on other ideas. Henry pushed on, not only by co-writing a book with Greg Cochran, but also by continuing to do original research.

I would like to say that Henry was allowed to work in peace. That's how things are in a free society, no? Unfortunately, he was repeatedly warned to stop, subtly at first and then not so subtly. Last year, the Southern Poverty Law Center added his name to its list of "extremists"—a list that, curiously, omits people whose skin is darker than peaches and cream.

In its "Extremist File" the SPLC describes him as follows:

Harpending is most famous for his book, co-authored with frequent collaborator Gregory Cochran, The 10,000 Year Explosion: How Civilization Accelerated Human Evolution, which argues that humans are evolving at an accelerating rate, and that this began when the ancestors of modern Europeans and Asians left Africa. Harpending believes that this accelerated evolution is most visible in differences between racial groups, which he claims are growing more distinct and different from one another. The evolution of these racial differences are, in Harpending's account, the driving force behind all of modern human history. He is also a eugenicist who believes that medieval Europeans intuitively adopted eugenic policies, and that we should recognize the importance of eugenics in our own society. (Southern Poverty Law Center, 2015)
I would give that summary a D+.

- The book's argument was that genetic evolution slowly accelerated as modern humans spread outward from a relatively small area in Africa, beginning some 80,000 years ago. Much later, this acceleration greatly increased when farming began to replace hunting and gathering some 10,000 years ago. The actual Out of Africa event—when modern humans spread out of Africa some 50,000 years ago—was tangential to this process of accelerating genetic evolution, yet the SPLC summary makes it seem pivotal (perhaps to show that Henry was obsessed with black people?).

- The book's argument was that culture and genes coevolve: culture drives genetic evolution just as much as genes drive cultural evolution. And this process can take place within groups that are not normally thought to be “racial.”

- The last sentence is way off the mark. Yes, a culture will make it harder for some individuals to survive and reproduce, thereby removing certain predispositions and personality types from the gene pool, but this process is no more a "eugenic policy" than is natural selection itself. It's silly to use words like "eugenics" and "policy" for something that happens unconsciously in any culture, even in small bands of hunter-gatherers.

I don't mind people making unfounded criticisms. That's par for the course in academia. But was the SPLC interested in academic debate when it listed Henry as an "extremist"?

Indeed, what's the point of that list? Information gathering? Or is it more like incitement to extrajudicial punishment and, yes, extrajudicial violence? "Look folks, this is a BAD PERSON, so go and do what the justice system is too cowardly to do!" Isn't that the point of the exercise? And isn't that exactly what the KKK was condemned for doing?

A strange role reversal has taken place between the long-dead KKK and the SPLC. It's now the latter that tries to enforce its notions of good behavior through intimidation, veiled threats, public shaming, and blacklisting. It's now the SPLC that is conspiring, literally, to deny people their civil rights.

Anyway, Henry Harpending seemed unfazed by the SPLC's blacklisting. He was apparently one of those rare tenured professors who put his tenure to good use and blissfully went on doing what he had always been doing. I wish he had lived longer. He was irreplaceable not so much because he knew more but because he was unafraid to say and act on what he knew. I will miss him.


Cochran, G. and H. Harpending. (2010). The 10,000 Year Explosion: How Civilization Accelerated Human Evolution, New York: Basic Books.

Ehrlich, P. (2000). Human Natures. Genes, Cultures, and the Human Prospect, Penguin. 

Harpending, H., and G. Cochran. (2002). In our genes, Proceedings of the National Academy of Sciences (USA), 99, 10-12.  

Hawks, J., E.T. Wang, G.M. Cochran, H.C. Harpending, and R.K. Moyzis. (2007). Recent acceleration of human adaptive evolution. Proceedings of the National Academy of Sciences (USA), 104, 20753-20758. 

Lévi-Strauss, C. (1971). Race et culture, conférence de Lévi-Strauss à L'UNESCO le 22 mars 1971  

Southern Poverty Law Center (2015). Henry Harpending, Extremist Files,