Greg Cochran and Henry Harpending have a new book out, The 10,000 Year Explosion: How Civilization Accelerated Human Evolution. It expands on a paper they and others published last year, which I wrote about then.
The book’s website has a wealth of material, so I won’t belabor the point, but in brief their argument is that over the last 10,000 years, roughly since the beginning of agriculture — both the domestication of animals and the planting and harvesting of crops — human evolution has been happening faster than it ever did earlier in the history of the species. Faster, as in 100 times faster.
There are two principal, interacting, reasons. First, agriculture allowed people to live in larger and more densely settled groups, which altered the selective pressures influencing reproductive success. Different foods, different diseases, different social expectations — all changed which people were more likely to have children who themselves lived long enough to successfully raise children of their own. Not much more likely, usually, but a very small percentage advantage is powerful enough to sweep a whole population in a lot less than 10,000 years.
Second, agriculture supported a much larger total population, meaning more mutations, more bodies testing whether this version of a gene or that offered better odds in the lottery that pays off in more descendants. And there’s no rule that limits players in the lottery to buying just one ticket. Many different genetic changes may be happening simultaneously in a population.
There’s been plenty of discussion on blogs for you to explore, but you could start with 2blowhards, which did a weeklong series of interviews with Greg Cochran. Check the archives for the week of Jan. 25.
And Steve Sailer has a great review he wrote for VDare. Michael Blowhard calls it “rowdy.” I think I’d go for “rollicking” myself. Sailer writes, “Perhaps my gravestone will read, ‘He introduced Cochran to Harpending.’ ”