A Troublesome Inheritance: Genes, Race and Human History, by Nicholas Wade. Penguin Press, 278 pages, $27.95.
I wanted to like Nicholas Wade's A Troublesome Inheritance. The book begins well enough, with a nice roundup of what genomic science has told us about human evolution and migration. But the author then proceeds to offer some highly speculative hypotheses about why different social, cultural, and economic practices appear among different human groups. He has clearly outrun his data.
First, the science. Wade, a former science reporter for the New York Times, wants to gore the ox of the political correctness when it comes to the topic of race. Does it make sense to categorize people by groups, he asks—and if so, which groups?
Let's hop for a moment into the WABAC machine to visit the White House ceremony in 2000 celebrating the publication of the first draft of the human genome. On that occasion, private genetics researcher Craig Venter noted that his company had sequenced the genomes of five individuals including people identified as Hispanic, Caucasian, Asian and African-American. His company did this, Venter said, "to help illustrate that the concept of race has no genetic or scientific basis."
As Wade correctly points out, "Different populations don't have different genes—everyone has the same set." Perhaps this is the point that Venter was trying to make. However, genes often come in variations called alleles that usually arise through mutation and are responsible for such hereditary differences as eye and hair color, the ability to digest milk as an adult, and greater resistance to malaria. It is thus possible to slice genetic human diversity into all sorts of groupings: brown-eyed versus blue-eyed versus green-eyed races, or the milk-digesting race versus the milk-indigesters. Identical twins aside, each person is genetically unique, so the reductio ad absurdum is that every individual belongs to a "race" of one. Perhaps it should be thus, but doing that means ignoring some interesting questions about human history and evolution.
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Wade argues that people can be coherently sorted into various groups based on the differential frequencies of alleles. Some groups carry a higher percentage of certain alleles than other groups. Wade reports that geneticists can use clusters of so-called ancestry informative markers (AIMs) to reliably identify the continents of origin of any particular individual's ancestors.
Wade relies heavily on research by the Stanford geneticist Noah Rosenberg, who noted in the journal Human Biology that "despite the high levels of similarity across populations, the accumulation of small differences across large numbers of markers enables inference of geographic ancestry." Researchers can set their computer programs used to probe AIMs to reveal ever-finer allele clusterings. Set the programs to three, and they sort human beings into Africans, Europeans/South Asians, and East Asians. Set them to five, they sort humans into basically five continental groups, now including Australasians and Amerindians. Rosenberg points out that "the pattern of human genetic similarities and differences can be explained as the outcome of a human expansion out of Africa via a process in which new migrating populations each carried only subsets of the variation from their parental populations, and in which major geographic barriers have historically had reduced permeability to human migration."
Wade argues that human evolution has been recent, copious, and regional, with something like 14 percent of genes in human beings showing some signs of being subject to recent selection pressure. He also makes the uncontroversial claim that natural selection doesn't just work on the genes that determine characteristics such as skin color or lactose tolerance but also on the genes that shape brains. If genes shape brains, then they also shape behaviors.
Wade suggests that the evolution of social behaviors "necessarily proceeded independently in the five major races and others; and that slight evolutionary differences in social behavior underlie the differences in social institutions prevalent among the major human populations." Wade acknowledges that "this thesis is unproven," but challenges critics to show "why social behavior should have been exempt from natural selection."
Clearly the advent of agriculture 8,000 years ago has resulted in differential genetic makeups for various groups. For example, researchers find that 70 percent of people living in populations whose ancestors have been farming for a long time tend to have six copies of the gene for the protein amylase, which helps to digest starches, whereas only 37 percent of those whose ancestors depended more on meat consumption have that many copies. Surely farming shifted the frequency of various gene combinations that affect behavior as well. Wade argues that farming and urbanization were the selective sieves through which European and East Asian populations have passed differentially selecting allelic variants for various behaviors.
This is where the argument starts getting shaky. Wade spins out speculations that genetic variants encouraging trust, propensity for hard work, and innovation became more frequent among Europeans; that variants for authoritarianism and social conformity became more frequent among East Asians; and that because Africans' ancestors were less subject to farming and urbanization, they retain alleles that incline them to fractious tribalism. But researchers have not yet identified gene variants that would account for such behavioral shifts. Until they do, it's an open question how much such genetic variants help explain social, economic, and political institutions. Wade comes perilously close to flirting with a kind of genetic determinism.
Wade asserts several times that it should be easy for other groups to adopt the prosperity-producing combination of Western social, economic, and political institutions—markets, rule of law, democratic governance, and so forth. The fact that so many groups have not done so is, he argues, evidence that the "core social behaviors of each civilization have an evolutionary foundation" that evolution consequently "exerts an unseen collar on the pace of history." He argues that genetic changes among Europeans loosened that collar over the past few centuries.
Wade's singular focus on genes causes him to ignore the fruitful hypothesis that a different form of natural selection operates on human institutions. Institutions might be thought of as memes, variants of which arise more or less randomly, like genetic mutations. These variants, again like alleles, may or may not enhance the reproductive fitness of their carriers. The economist F.A. Hayek suggested that human evolution and history is a trial and error search through time in which thousands of societies and billions of people tested different religious, political, family, and economic institutions. Over time, some groups out-reproduced and out-competed other groups. The institutions that helped some groups succeed against other groups can be thought of as embodying an ever better understanding of our human natures.
Wade does admit that "rapid change must be due to culture, not genetics." Just so. And what does he think has been happening over the past two centuries? Once the set of institutions that more or less define open societies came into existence, they began out-competing societies that did not have those institutions. In his 1991 book The World Revolution of Westernization, the Yale historian Theodore von Laue describes how the spread of Western institutions by means of both arms and intellectual seduction has provoked resistance but is displacing other economic and political arrangements. And Western institutions—with fits and starts—have been spreading and adopted by other human groups.
For example, according to the Fraser Institute's economic freedom calculations, the "average level of economic freedom…has increased from 5.30 in 1980 to 5.76 in 1990 to 6.71 in 2000 and finally to 6.83 in 2010." Freedom House similarly reports that the percent of free countries has risen from 25 percent in the 1970s to 46 percent today, and that the percent of not-free countries has correspondingly fallen from around 40 percent to 24 percent. Clearly genetic changes do not account for these significant shifts.
Wade concludes that his book is an attempt to "dispel the fear of racism" and to "begin to explore the far-reaching implications of the discovery that human evolution has been recent, copious and regional." Undoubtedly future researchers will more finely detail how cultural and genetic evolution have mutually reinforced one another to shape human behaviors. And perhaps the implications of their findings will be "far-reaching." But Wade simply hasn't the data to back up his speculations.
In any case, whatever those future genetic findings might be, they will not be nearly as far-reaching in their implications as the discovery of the institutions of liberty.
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