Gregory Cochran (1) (1953–)

I like challenging views and people who dare to go against the grain, and dare to knock down sacred houses. Cochran and Harpending are clearly of this caliber. To begin with, their book is a frontal attack on the existing consensus in the (social) sciences regarding the biological and cultural evolution of man. They accuse those sciences of remaining blind to the fact that human, biological evolution is also determined by cultural factors. They confront the reader with a veritable bombardment of theses about three defining periods in which this would be visible: the 'jump' in the cognitive capabilities of Homo sapiens through the introduction of Neanderthal genes about 40,000 BP, the enormous genetic changes resulting from the agrarian revolution about 10,000 BP and finally the extraordinary increase of intellectual powers among Azkhenazim Jews in the period between 800 and 1600 of our era.
Cochran and Harpending support their argument with numerous references to existing genetic and biological studies, but only in a third of the cases do they add names and valid scientific references. Moreover, their text is full of twists and turns like “it could be”, “it is very well possible”, “there are hints that”, “there's reason to think that”, etc. In other words, we are fully in the domain of speculation.
Now I think well-founded speculation certainly has its place in the scientific process. Scientific practice is always accompanied by some degree of hypothetical thinking, based on reasonable and rational arguments. Thus, even without empirical evidence, theories are certainly valuable (theoretical physics is full of them), as long as they are soundly grounded and sufficiently explain certain phenomena (until proof to the contrary). To a certain extent this also involves an element of intuitive thinking, as is apparent from the work of Stephen Hawking, for example. And the results can be ground-breaking.
Evidently, Cochran and Harpending are convinced that their hypotheses are ground-breaking. But they fail to substantiate this in a scientifically sound manner. The arrogant tone they regularly use towards other scientists is therefore all the more offensive. I am not making any statement about the potential plausibility of their speculations. In the case of the possible interbreeding between Neanderthals and Homo sapiens, for example, their claim has been proven in retrospect, through sound genetic research. But it is typical that they go one step further and conclude that the input of those 'foreign' genes has brought the cognitive development of modern humans to a much higher level. With this statement, and many others, they are entering very dangerous territory.
More on that in my History account on Goodreads: https://www.goodreads.com/review/show/900951103… (mais)

I remember, back when I was in college, participating in one of those classic college-style drunken debates with some friends about whether evolution was speeding up or slowing down. I argued, no doubt with some slurring of words, that that the increase in the complexity of life meant that there were more and more things for evolution to operate on, and that therefore evolution was speeding up. They argued the opposite, that evolution was fastest back when organisms were simple, and a change in allele frequency would have been proportionately larger as a percentage of the gene pool.

Obviously from the sober light of day years later this was an argument over semantics, how we were defining the base unit of comparison, but I still sometimes encounter the equivalent opinion that evolution for humans has either slowed or stopped, backed by the contention that humans in particular are now somehow beyond the laws of natural selection governing the lesser inhabitants of the earth. Cochran and Harpending have a fairly slim popular science book that takes aim at that same misconception that bothered me, but while I agree wholeheartedly with their thesis that humans are not somehow exempt from evolution, I have a few qualms with the book.

For the most part it reads like a counterpart to the frequently-cited Jared Diamond's Guns, Germs, and Steel, in that while Diamond spent a lot of time talking about how Europeans benefited from having more and better domesticatable plants and animals and the like, he did not concentrate as much as he could have on how much of a two-way street that was, meaning the symbiotic nature of the evolutionary pressures humans were putting on those plants and animals. Put crudely, ancient humans spent a lot of time domesticating things like horses or corn, and since doing that gave groups which were successful advantages over other groups that weren't, you could look at that domesticating process as not only selecting future horses and corn, but also future humans who were better at at the domesticating process itself. Once humanity realized that it had the power to manipulate its environment, that unleashed a self-reinforcing cascade of selective forces, which are not only still operating today, but could very well be speeding up.

I agree wholeheartedly with this basic idea, and for the most part C & H do a solid if somewhat breezy job of explicating it. Their main sin (which of course is also a virtue in the popular science market) is that they are so confident in their theory of accelerating anthropogenic selection pressures that they seemingly incapable of devoting more than a few dismissive sentences to previous research or competing views. It makes the book livelier and more readable, but you can't help but be a little suspicious of the result. So you will have controversial sections like the opening one on possible interbreeding between ancient homo sapiens and Neanderthals that are very interesting and seem to make compelling logical sense, yet to a layman deliver an impression of either non-engagement with or the passing over of broad swathes of scientific work. That comes with the pop-sci territory though, and since I'm not a genetic historian, I will give them a pass on the question of accuracy.

At its core, this book is about the self-domestication of society, a process which has been going on for several thousand years, but over the past few millennia (and the past few centuries in particular) had dramatic effects on human behavior. Scientists like Steven Jay Gould have assumed that humans have been mostly unchanged for the past few thousand years, but Cochran and Harpending strongly disagree, using analogies like the rapid changes in species like dogs and data on specific subgroups of humans with unique selection pressures (more on that later). It's impossible to overstate the dramatic effect that the invention of agriculture had on homo sapiens. It was a complete game-changer in terms of sustenance, culture, warfare, and our relationship to the environment. There's a good discussion of subtleties in the Malthusian trap, the theory whereby any increase in food production is quickly eaten up by the resulting increase in population. This is true in broad terms, but the quantitative and qualitative difference in lifestyle that agriculture provides is the catalyst for an immense speedup in the churn of genes. It upsets the balance between deaths from conflict, disease, and starvation (pestilence, war, and famine, if you want to get Biblical about it), which matters from a selection standpoint. Groups of humans that master agriculture will not only be better fed, but they will have enough surplus to devote to increasing the complexity of their civilization as well as having different immune systems due to contact with livestock and other animals. C & H speculate that the dramatic expansion of Proto-Indo-European-speaking tribes might be due to the advantages conferred by lactose tolerance, and there's also the familiar example of the contrast between European colonization of the Americas thanks to diseases like smallpox and the failure of the same (except in South Africa) due to lack of resistance to malaria.

Where the book gets the most controversial is in claiming that this process of adaptation is having effects within several human generations, aiming squarely at Gould's contention in books like The Mismeasure of Man that the basic hardware of humanity hasn't changed much in the past few tens of thousands of years. I can certainly agree that it seems like there's been an increase in traits favoring abstract reasoning since the Bronze Age. The human environment we find ourselves in today is simply not like the small scattered settlements of a few thousand years ago, and as witnessed by the dramatic explosion in diversity of species like dogs that undergo rapid, determined selection pressures, it's perfectly possible that we have been consciously or unconsciously breeding ourselves in particular directions that favor success in modern society. Modern society might also create many avenues for misusing those traits of abstract reasoning and logical deduction (endless fan-wiki pages on obscure TV shows are a good example of these faculties gone awry - this is on a surface level identical to doing real knowledge work, but is completely sterile), however it seems reasonable to say that, Idiocracy aside, smarter people might have a definite reproductive advantage in environments that reward cleverness over the long haul.

Does that mean that we could see groups of people today who are measurably smarter than others? To be as blunt as the final chapter, are groups like Ashkenazi Jews or East Asians simply smarter than "generic" Caucasians, as seen by their greater average IQ scores and disproportionate success in fields that demand high cognitive complexity? To be even blunter, by that same reasoning does that imply that groups like sub-Saharan Africans or aboriginal Australians simply less smart than "generic" Caucasians? Cochran and Harpending, to their credit, present this contention with as positive a spin as you could expect, casting this investigation into potential genetic differences between groups as an opportunity for more research and possible positive gene therapy rather than as justification for something like apartheid or a Brave New World society. Certainly nothing in an acknowledgement that some groups might have a higher mean IQ than others implies any kind of justification for racist policies any more than acknowledging that an individual might have a higher IQ than another does. But given the high temperatures that accompany any research that even glancingly appears to support eugenics or racial determinism (witness the shameful "Wilson, you're all wet" treatment that E. O. Wilson received), plus all of the well-known historical failures of pseudo-scientific intelligence testing, I'd like for further studies and for books that don't seem so flippant. I don't believe we have anything to fear from further research into the genetic basis of human intelligence - far from it. Let's just make sure we proceed with a little more rigor than I did as a drunken undergraduate.… (mais)