The Son Also Rises: Surnames and the History of Social Mobility (The Princeton Economic History of the Western World) Paperback – August 25, 2015

The social sciences and humanities are in trouble. They are largely predicated on the erroneous idea that social forces divorced from genetic endowments are responsible for producing the broad social patterns we observe. Professor Clark has been challenging this view for years, and devising hypotheses that will prove to have much better explanatory and predictive power as the science of genetics matures.Due to the technicality of its subject, the chapters of The Son Also Rises are difficult to read. But the chapter introductions and conclusions are a gold mine of insight. Among the many things you'll learn from Clark's book is the importance of distinguishing the social phenotype (the sum of one's observed characteristics) from the social genotype (one's underlying genetic characteristics).According to Clark, in order "to discover the likely underlying social genotype of your potential partner, you need to observe not just their characteristics but also the characteristics of all their relatives... This social *genotype*, rather than the observed social *phenotype*, is what your children will inherit” (p. 283).To take a simple example, “Suppose you are faced with a choice of two marriage partners, both of whom have a high-status phenotype. They are both graduates from elite colleges and have PhD’s in philosophy, for example, or both are board certified in rhinoplasty. But one partner is of Ashkenazi Jewish background [group average IQ of 110] and the other of New France descent [group average IQ of 85]. Then the predicted status of your children will be higher if you select the Jewish partner” (p. 285).Eventually, the kind of sophisticated behavioral genetics in Clark's work will be more widely incorporated into the social sciences -- at least if they're going to successfully predict and explain social phenomena in a deeper way than they currently do. This book will represent one of the first matches that starts the conflagration that will revolutionize social science.

[major edit: I spent a couple days working through the math, and checking it with my own simulations, and have convinced myself that my earlier mathematical reservations were completely wrong. I've changed the review to reflect that]The "Son Also Rises" was a fascinating read that seems likely to provoke controversy, but also to advance evidence-based discussions of equality and social mobility. Clark makes two major (somewhat separable) arguments in "Rises". First, that social mobility is much lower, and consistent across societies than anyone would have predicted. Second, that this low-mobility is biologically (in fact genetically) based. The first argument is better supported than the second. Clark's strong genetic conclusions seem rely on unassailable modelling (I tried) but some shakier genetic conclusions. They can't be dismissed entirely, however. Clark's evidence and reasoning is strong enough that the burden of proof is squarely on those who disagree with him. The implications the modern reader is left to draw are unsettling.Clark's conclusions about the facts of mobility are astonishing. Typically, studies of mobility showed that intergenerational correlations (parent-offspring, typically father-son) in wealth are on the order of 0.4. This suggests ancestor-descendant correlations in wealth should be unobservable after about 4 generations. Across many cultures and times, and many different measures of status, Clark notes that identifiable elite or low-status groups regress to the mean at a rate between 0.75-0.85. This means that in fact differences in status persist for more than 10 generations.Technically, Clark here models status as a single order Markov process, with three major components: time, [measurement] error, an underlying [latent] "social inertia" (my name) term. By this he emphasises we can model inheritance of social status from one's parents in exactly the same way we do height or eye color based on genetics. He notes that if we do so, we don't need to invoke any more complicated processes to explain the observed data (such as the status of extended family).It turns out he's completely right about the models. I checked. If you model the inheritance process without the underlying latent term, you fail to match the data he's presented. If you model the process in the same way you would model additive genetic inheritance you get exactly the right answer. (I did this assuming a heritability of 0.4, parental-midpoint genotypes for the kids, renormalised mean and SD every generation, and a modelled range of assortative mating based on phenotype. I took beta and b vales from a number of the examples presented in the book.)But here is where we begin to need to exercise caution. As a colleague is fond of quoting, "All models are wrong, but some are useful." We shouldn't let the simplicity of the model force us into a hasty overinterpretation of the underlying mechanisms. Clark jumps to a much less-cautious genetic interpretation of his results than almost any behavioural geneticist would (or at least should). Inheritance can be both genetic and epigenetic. Epigenetic is just a term that describes inheritance by any means but DNA (this isn't a magical thing: think language or religion). For instance, some primates and hyaenas inherit rank from their mothers. Fetal nutrition, maternal stress, early-life stress, and even languages and dialects, have effects on status and all have effects that are known to be transmitted across generations. Famously, maternal grooming in rats has profound (non-genetic) transgenerational effects on a range of personality measurements. It is extremely difficult to separate epigenetic and genetic effects when studying heritability.Clark claims that because he can model inheritance of status as a first order Markov process, it actually is a first order Markov process based on transmitted characteristics inherent in the parents. Therefore, he claims, status is a deterministic product of a genetic "social competence" (his term). This is a strong claim. To his credit he discusses possible objections (such as inheritance of social networks). He also tries to quantify the non-genetic component of status in the best way possible, by examining adoption studies. Two studies, one on Korean adoptees in America, and another on adopted vs biological offspring in Sweden, seem to show a genetic heritabilty of income or education (here proxies for status) many times higher than conferred familial status.The magnitude of these results is certainly far too high, as any number of factors (such as differences in the way parents and society treat adopted and biological children---see Hannah Williams) will bias these numbers. But at the very least we can find no reason to reject Clark's model, and I was persuaded that there is likely to be a higher effect of genetics on status metrics than I would ever have previously expected. Clearly more, and better, studies need to be conducted in this area.At this point, any reasonable modern reader will be squirming. Raised under the spectre of the effects of early eugenics, racial determinism, and Manifest Destiny, we are rightly disturbed by attempts to reify social differences with biology. I'm reminded of the unproductive furor around "Sociobiology" and "The Bell Curve" (and Gould's error-filled attempt to rebut "The Bell Curve"). Clark spends much time demonstrating that there are no simplistic racial superiority claims to be taken from his data. His biologizing of hereditary class is inescapable, however. He tries to sugarcoat these interpretations with bland liberal prescriptions and platitudes, but they still rankle.There have been notable failures in trying to increase social mobility (like Head Start in the US). But other recent studies have shown that good urban planning (access to public transport, and jobs, and good schools) can dramatically increase social mobility. Even if there is a genetic component to social status, Clark has almost certainly exaggerated it. Genetics certainly doesn't preclude other measures to increase social mobility. Then too, as Clark notes, inequality and mobility are different things, and we shouldn't confuse them.In the end, "The Son Also Rises" was a thought provoking book, and one I'll read carefully again. I'd recommend it, as long as the reader doesn't accept any of the major conclusions without consideration.

Michael Clemens observed that in two books, Greg Clark has managed to remind us of a writer from Michigan: First, "A farewell to alms," and now "The son also rises." Imagination runs wild in search of, "What next?"The message is straightforward if not simple: Heredity matters. There are more Pepys at Oxford in the 20th century than chance alone could have predicted. There are thirteen surnames of elite standing in north Zhejiang and south Jiangsu that have managed to survive well into the Peoples Republic of China. Genes matter and changing the standing of families has taken generations.Piketty says we are headed back to a Gilded Age; Clark's studies support that view with vigor. Too bad his excellent book appeared without the recognition accorded "Capital in the 21st century."

It is a fascinating book. I wish I would read it 30 years ago. However, it’s strong opinion is also very misleading if you cannot read it objectively and think in a more dynamic context.

A fascinating work which exposes a lot of contemporary myths about social mobility. If you are interested in family history and have worked out your genealogy it provides a fresh perspective too. The more I think about this topic, the more it makes me realise that a society of perfect social mobility would be absolutely hellish!