Eric Michael Johnson reviews Nicholas Wade's A Troublesome Inheritance, over at Scientific American:
Wade seeks further support for his hypothesis that Europeans evolved to be more peaceable and tolerant in the experiments of Soviet biologist Dmitriy Belyaev. By breeding wild foxes, Belyaev showed that selecting for tameness could produce animals that were just as doting as domestic dogs in only 30 to 35 generations. Wade calculates that there have been 24 human generations between the year 1200 and today, “plenty of time for a significant change in social behavior if the pressure of natural selection were sufficiently intense.”
This selection pressure, Wade says, was an agrarian economy and the Industrial Revolution. Individuals who were more productive, and delayed their gratification by saving instead of spending, gained wealth at a faster rate and had larger families. (Wade cites one estimate from England suggesting that those with £1,000 or more at death had an average of 4 children while those with less than £25 had only 2). But, because there were a limited number of upper class families, most wealthy children had to marry beneath their station. These genetic entrepreneurs carried with them their industrious DNA down to the commoners.
Their social descent had the far-reaching genetic consequence that they carried with them inheritance for the same behaviors that had made their parents rich. The values of the upper middle class—nonviolence, literacy, thrift and patience—were thus infused into lower economic classes and throughout society.
This argument suffers multiple problems, two of which are particularly crippling. First, artificial selection, such as Belyaev used in his fox experiments, can produce novel forms much faster than natural selection can. Belyaev’s fox breeding experiment identified the tamest individuals in each generation and mated them together. But, according to a genetic analysis carried out earlier this year by UCLA biologist Adam Freedman and colleagues, it took about 2,000 years for the evolution of dogs from wolves to result in distinct populations (from 14.9 thousand years ago to 12.8 thousand years ago). At an average breeding age of 3 years, this means it took around 670 generations for the split to take place — far longer than the 35 generations Belyaev’s experiment required. Even then, these dogs would not have been as tame as domestic dogs today. Dogs became fully domesticated only through artificial selection within the last few hundred years, as dog breeders selected the traits they wanted in different varieties. Therefore, it is a huge mistake to assume that Belyaev’s breeding experiment can be directly translated to recent human history in Europe.
The second problem with Wade’s argument about the gentility of the English is more central to his thesis. Even if we assume that genetics is primarily responsible for “nonviolence, literacy, thrift and patience” (which it is not), there would still need to be evidence of a clear reproductive benefit in order for these behaviors to be “infused into lower economic classes” by having sex with the rich. Wade’s evidence for larger families among the wealthy in England (the only data Wade cites) comes from the 2008 book A Farewell to Alms by economic historian Gregory Clark. However, while Wade highlights how the richest 1% had twice as many children as the poor majority, he conveniently omits what Clark determines just three pages later, which is that this relative increase lasted only a very short time. This omission says a great deal about Wade’s commitment to both science and journalism.
More here. Also see reviews by Andrew Gelman, Agustin Fuentes, and Arthur Allen.