Review of "The 10,000 Year Explosion" by Gregory Cochran and Henry Harpending

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I’m not sure I can add anything helpful in a review of this book beyond pointing to the interview which ends here (but links to the earlier parts are available) and recommending beginning with the “HNU: human neurological uniformity” section.  Here are some thoughts anyway.

The official version of human evolution includes the doctrine of what Mr Moldbug calls human neurological uniformity.  The doctrine, as described in The 10,000 Year Explosion is: “that human evolution stopped a long time ago-in the most up-to-date version, before modern humans expanded out of Africa some 50,000 years ago.”  The reason that this hypothesis has become a doctrine is that the end of evolution necessarily implies that all human minds by the same everywhere – HNU for Mr Moldbug or the “psychic unity of mankind” in the book.

The book sets out to destroy the belief that evolution stopped 50,000 years ago by chronicling evidence of more recent evolution – and thus presumably refuting the theory (unfortunately this doctrine has left the realm of science and entered into the realm of liberal ideology, it thus has nothing to fear from evidence which proves it wrong).  The authors go further and argue that human evolution has been faster during the last 10,000 years that it was in the past.  Perhaps they overreach a bit here, but the idea that the evolutionary process ceased completely 50,000 years ago smacks of creationism.

It seems that the weaker belief that evolution has, in fact, occurred in the last 50,000 years would be the null hypothesis.  After all, it’s obviously true.  People look different now – as the authors point out, you wouldn’t mistake a Finn for a Zulu.  The idea that all populations of humans that left Africa over the last 50,000 years all ceased to adapt to their surroundings, or evolved in the exact same way, seems impossible.  We know that skeletons from even 450 years ago have skulls that are shaped differently than our own, for example.  The authors compare European incursions into the Americas versus European incursions into Africa.  The Amerindians had not evolved defenses against diseases – they were promptly wiped out.  The Africans had defenses against diseases.  The African continent also had diseases that the Europeans did not have evolutionary defenses against.  The results speaks for themselves and are of tremendous consequence.

In simple terms, the authors’ contention is that mutations that have even small benefits (say that, on average, they give a person with the mutation 2.1 children as opposed to 2.0 children for those without the mutation) will have significant effects on the population after 50,000 years (roughly 2,500 generations).  Simple adaptations can have giant impacts.  Moreover, the total population of humans was growing enormously.  Mutations should have been much more frequent.  The authors’ devote a great deal of time to agriculture (indeed there is a high correlation between how early a society adopted agriculture and that societies economic development in recent decades).  They believe that adaptations that made people deal with the new, agricultural diet in better ways would have had more surviving children, thus spreading those variants.  One mutation they discuss at length is one that allowed people to tolerate lactose – which is common (almost universal) in Europe and India, but less common (almost non-existent) in many other regions.  Perhaps even time preference was a function of evolution – certain groups may have evolved to be more willing to delay gratification or become civilized by Hoppe’s definition.  This would have helped these groups become wealthier, over time, and therefore reproduce more.

Other things make clear that genetic material would not have been passed-down randomly as seemingly would be required by the hypothesis that we all have identical neurological systems.  Roughly 16 million present-day men in Central Asia are direct descendents of Genghis Khan.  In many societies, wealthy people were able to raise more children to adulthood.  Do we really believe that certain traits might not have some people more likely to, say, die in wars?  Much of the history of even the last 10,000 years would have seen genetic material spread through invasion and ransacking.

The authors sum up their own views, as follows:

Human evolution didn’t stop when anatomically modern humans appeared, or when they expanded out of Africa.  It never stopped—and why would it?  Evolutionary statis requires a static environment, whereas behavioral modernity is all about innovation and change.  Stability is exactly what we have not had.  This should be obvious . . .

Agreed.  The authors may overstate some points and make conjectures that will turn out to be incorrect.  But this larger point is certainly true.  In fact, the arguments that evolution stopped 50,000 years ago seem to get awfully similar to arguments made by creationists.

I would like to make one slight critique.  Near the end of the book, the authors castigate those who believe that human nature is fixed.  Most often those who argue against a fixed human nature are arguing in favor of more schooling to make everyone equally smart – or some such.  Certainly human nature is derived from genetics.  Equally certainly, we won’t see meaningful changes in this genetically derived human nature in our lifetimes.  So, for all intents and purposes, I see no harm in assuming that human nature is fixed.

2 Responses to Review of "The 10,000 Year Explosion" by Gregory Cochran and Henry Harpending

  1. […] think the book goes best with Understanding Human History and The 10,000 Year Explosion. If I take a meta-lesson from these works it’s that evolution is constantly happening, […]

  2. Ted says:

    So far The 10,000 Explosion has not provoked the hostile invective that greeted The Bell Curve. I would like to think that the reading public, and the intellectual community has become more accepting of biological explanations of individual and group differences.

    Unfortunately, it may be that the guardians of political correctness have not detected this book’s presence yet. The 10,000 Year Explosion explains the evolution of racial differences that are documented in The Bell Curve.

    The longer a racial group has practiced agriculture and urban living the lower its crime rate, and the higher its average intelligence are likely to be.

    http://www.nationmaster.com/graph/cri_mur_percap-crime-murders-per-capita

    http://en.wikipedia.org/wiki/IQ_and_the_Wealth_of_Nations

    Proclivities that increased one’s chance for survival during the stone age are more likely to earn one a prison sentence in a civilized country, or a date with the executioner.

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