In an earlier posting, “Not Smart Enough to Be Rich?” I described economist Vittorio Daniele’s response to intelligence researchers Richard Lynn and Tatu Vanhanen’s argument that differences in IQ explain the relative poverty of some of the world’s countries.  In a new book titled A Troublesome Inheritance, N.Y. Times science writer Nicholas Wade treats Lynn and Vanhanen’s work as respectable evidence not only for a link between IQ and national wealth, but for linkage between genes, race and IQ.  At the risk of giving Wade’s book attention it doesn’t deserve, let me expose it to some reality testing.  The bottom line is that the book provides a nice exposition of ideas about the development of cultural differences and their likely relation to economic outcomes, a reasonable argument about the current impossibility of ruling out a small genetic component, and no direct evidence of any kind for genetic underpinnings of differences in intelligence, future orientation, or any of the other traits discussed.  In the end, A Troublesome Inheritance is a rather sorry display of how far a reasonably well-read and oft-times informative science writer is ready to go to stoke controversy in order to sell books.  As an insider to the economics literature on long period cultural change and economic development, I can tell you that Wade, who spends many pages criticizing what economists say about the matter, has done very little homework here, missing most of the relevant recent literature in economics in favor of one obscure book and a few well-known names.

Early in his book, Wade spends many pages describing the dark side of racism and eugenics, to make sure that we know that he knows that he is about to play with fire.  He then asserts that we’re now sufficiently mature and aware of the subject’s dangers to graduate from the 20th Century struggle against racism led by figures like the anthropologist Franz Boas.  We’re ready to enter into frank scientific discussion that admits to the possibility that different races have evolved in different ways during the sixty thousand some years since the ancestors of Europeans, East Asians, Pacific Islanders, Amerindians and others left Africa.

Wade’s argument that the people of different regions and cultures could have different frequencies of genetic alleles disposing them towards the development of different cognitive abilities or inclinations with respect to hard work, delayed gratification, and violence, is neither original nor objectionable in principle.  That a fixed and uniform human nature emerged before modern humans spread from Africa, with the subsequent dozens of millennia providing insufficient time for significant change to have occurred, is clearly difficult to defend a priori given that such time spans have been quite adequate to the evolution of other traits, including ability to digest lactose beyond childhood (attributable to separately evolved adaptations in Europe and in sub-Saharan Africa), or the expanded lung capacity for living at high altitudes found in some Tibetans and peoples of the Andes.  Scientists have identified numerous strings of genetic code that serve as good indicators of the region in which ancestors lived prior to the increased movement of populations that came with European conquest and exploration starting in the 15th Century.  And one can point to various instances in which behavioral traits have been bread into domesticated species within a relatively small number of generations.

But there is as yet no concrete evidence that any of the identified DNA strings that differ in frequency among populations gives rise to distinct behavioral propensities or cognitive abilities.  Except in the case of some genetic diseases, the helpfulness of differences in DNA strings as markers is thus far no different from that of fingerprints, which differ from person to person but don’t translate into differences in ability to use a smart phone or play the piano.  So a scientifically literate person who plunges into Wade’s book, as I did, anticipating a discussion of new evidence of genetic differentiation of intelligence and behavioral traits by region, will be surprised—given the book’s packaging—to find its complete absence.  Instead, the book simply provides a prolonged argument about why one can’t rule out the possibility of genetic underpinnings to much-studied differences between members of different cultures, accompanied by assertions that the evidence is already there, and accusations that those who deny this are intellectual cowards.  These accusations might have been justified if Wade had any actual genetic or heritability evidence to present.  Since that isn’t the case, and since moreover Wade repeatedly throws scientific caution to the wind, as when he asserts that there are three main races (as if the people of Africa were more genetically homogeneous than those of the rest of the world, whereas the science supports quite the opposite view), one is forced to conclude that Wade’s own seeming bravery is little more than a relaxation of scientific standards for the purpose of selling books.

This is really too bad, because Wade offers an interesting reading of cultural histories and their intersection with economic outcomes, one that overlaps considerably with the arguments on how differences in early economic and social adaptations explain inequalities of income among regions of the globe today that I included in my book The Good, The Bad and The Economy. The later chapters of that book introduce lay readers to a growing literature by economists on how differences in the evolution of societies over the very long run, especially differences in the timing and extent of spread of and contact between agriculture-based civilizations, determined the differences among world regions on the eve of the colonial era, and how that era in turn set the stage for the recent decades of differential economic “catch up.”  While much of Wade’s discussion is stimulating, if viewed as a review of ideas about the geographic persistence of divergent cultural traditions and their potential application to global economic inequality, he unfortunately misses the entirety of the relevant literature in economics, unless one includes in that category the somewhat related but problematic book Why Nations Fail.*  Had he done his homework, he would not have focused his discussion of economists’ writing on the latter and on a book by economic historian Gregory Clark, but would have noticed the work of my co-authors and me, of my colleague Oded Galor and co-authors, of William Easterly and collaborators, of Enrico Spolaore and Romain Wacziarg, and more (a recent review by Spolaore and Wacziarg lays out the territory).**  To say that economists, apart from Clark, have been ignoring how differences in attributes transmitted over generations affect global inequality, would not pass scrutiny among attendees of several recent economists’ meetings on the topic.

Whether there is genuinely genetic as well as cultural transmission contributing to the impressive persistence of traits within national or ethnic groups over many generations is an intellectually interesting question that scientists will need to explore with care as relevant evidence begins to become available.  Unfortunately, Wade’s impatience to see the question engaged may have set the field back by playing into the view that to even discuss the topic is to show oneself to be a charlatan. There being no hard evidence of any pertinence in Wade’s book, let’s please move on, and in doing so, let’s keep in mind that the most important question here is how members of groups that have been disadvantaged by history can strengthen their abilities so as to more effectively share in the benefits that new technologies and forms of organization have begun to make available to all of us.   

* See my “Why Nations Fail and Why Investing in People is a Pre-requisite for Building Both Strong Institutions and Strong Economies,” at as well as my review of the book in the journal Economic Development and Cultural Change.

** See Spolaore and Wacziarg, “How Deep are the Roots of Economic Development?” in Journal of Economic Literature, 2013, at .

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