Saturday, March 23, 2013

Does the Clark-Unz model apply to Japan and Korea?

Syngman Rhee in 1905 and later South Korea’s first president (1948-1960). Though born into a rural family of modest means, he was of yangban and even royal lineage (source).

Why is mean IQ higher in East Asia than elsewhere? Ron Unz (2013) sees the key cause in a scarcity of land and women that continually condemned the lower classes to reproductive extinction, particularly among the farmers who made up most of China’s population. If a lineage remained poor for two generations in a row, it would die out and be replaced by downwardly mobile individuals from higher up on the social ladder. There was thus strong selection for men with enough business smarts to avoid poverty and amass enough assets to get married and have a family.

This model of selection seems valid for the Chinese but less so for the Koreans and the Japanese, whose strong class divisions should have impeded upward and downward mobility. Why, then, do these two other populations display similarly high mean IQ? As Unz (2013) notes:

Both the Japanese and the Koreans have done remarkably well in their economic and technological advancement, and also as small immigrant racial minorities in America and elsewhere. However, there is no evidence that rural life in either country had any of the major features possibly so significant for Chinese history, such as a total lack of feudal caste structure, an exceptionally commercialized system of agricultural production and land tenure, and the massive universal downward mobility due to equal division of property among male heirs.

Stripped down to its basics, the Clark-Unz model of selection has three key elements:

1. Class differences that reflect differences in intellectual performance.

2. A higher level of reproductive success in higher social classes than in lower ones.

3. No barriers to downward social mobility. The lower classes are thus gradually replaced by people of higher social origin.   

But surely these three factors prevail everywhere? No, not at all. Hunter-gatherers and simple agricultural societies have little or no social stratification. Other societies are stratified but have no State that can monopolize the use of violence. Upward mobility is thus an ongoing free-for-all that selects for other psychological characteristics, i.e., ruthlessness, charisma, and ability to mobilize gangs of young men. Finally, still other societies are so stratified that downward mobility is impossible. This is the case with the caste system in India, where the shame of “losing caste” deters downward mobility. In addition, the lowest castes can afford to reproduce because certain stigmatized kinds of work are reserved for them, so there is no need to replenish their ranks with people of higher social origin.

How do Japan and Korea fit into this picture? Before the 19th century, both were feudal aristocracies where the elites monopolized the use of violence. For the bulk of the population, there was thus little selection for “Big Men”, as is the case in societies where State formation is weaker. The question then remains whether Japan and Korea were caste societies. Did the lowest classes reproduce essentially on their own? Or were they replaced by a steady infusion of downwardly mobile individuals?

Among the Japanese lower classes, the Burakumin were the only real caste, in the sense of a group that lost few members through upward mobility and gained few through downward mobility. It is probably for this reason that the Burakumin differ so much from other Japanese in terms of behavior, personality traits, and intellectual performance. They seem to have preserved the mental and behavioral predispositions that were dominant in the Japanese population five hundred to a thousand years ago (see previous post).

Japan's class structure seems to have resembled Britain's. In both cases, there were attempts to codify class differences, and in both cases these attempts largely failed. The Britannica's description of Japanese society in the 18th and 19th centuries sounds very much like premodern Chinese society:
Inevitably it [commercial development] meant the rise of some wealthy members of the rural populace, who used their wealth to invest in land and commercial ventures and to "ape their betters" in the cities in both custom and culture. Few farmers, however, prospered through producing commercial goods, and the majority of peasants remained impoverished. Rural villages were characterized by a few wealthy farmers, a majority of small-scale independent landholders, and a growing number of impoverished tenants. Many small-scale farmers, squeezed by the demands of commercial development, were forced to part with their lands and fell into tenancy. (Britannica, 1998)

A similar situation seems to have prevailed in Korea, even though the yangban were theoretically guaranteed a privileged status by virtue of their high birth or success on civil service exams. Moon (1992, p. 204) describes impoverished yangban living alongside peasants and commoners as fellow tenants. Breen (2004) likewise describes numbers of yangban sinking into poverty without hope of gaining a government office.

The way a society works in theory often differs from the way it actually works. English society has long been described as having rigid class distinctions. Yet when Clark (2009) analyzed the transmission of surnames by social class, he found evidence of considerable social mobility going back to the Middle Ages:

Clark, for example, denoted in the middle ages anyone performing clerical work, including the minor orders of the clergy who were allowed to marry. Since literacy was extremely limited in medieval England clark was thus originally an upper class name. But by 1600 0.7 percent of the indicted bear this surname, as many as among rich testators (0.63 percent). Of the 11 indicted Clarks in my sample, 7 had their occupation listed as laborer, thus illustrating the downward mobility of the medieval educated elite. There was also sign of upward mobility. Cook in the middle ages would likely not denote someone of particular wealth or status. By 1600, however it was the surname of 1.3 percent of the richest testators. Among the seven rich Cooks, five were described as Yeomen and one as a Gentleman. Even medieval and early modern England was thus a very fluid society, with families moving up and down the social scale across each generation. (Clark, 2009)


Breen, M. (2004). The Koreans. Who They Are, What They Want, Where Their Future Lies, St. Martin’s Press.

Britannica. (1998). ‘Japan’, vol. 22, p. 293

Clark, G. (2009). The indicted and the wealthy: surnames, reproductive success, genetic selection and social class in pre-industrial England.

Clark, G. (2007). A Farewell to Alms. A Brief Economic History of the World, Princeton University Press, Princeton and Oxford

Moon, O. (1992) Confucianism and gender segregation in Japan and Korea, in R. Goodman & K. Refsing. (eds) Ideology and Practice in Modern Japan, Routledge.

Unz, R. (2013). How Social Darwinism made modern China, The American Conservative, March 11

Saturday, March 16, 2013

East Asia's Farewell to Alms

“‘How could any man in our village claim that his family had been poor for three generations? If a man is poor, then his son can’t afford to marry; and if his son can’t marry, there can’t be a third generation” China’s poor were continually removed from the gene pool, their places taken by downwardly mobile individuals (Woodblock of farmer, Wang Liangjian, 1939, source)

Mean IQ is unusually high in East Asia, averaging around 106 among Han Chinese, Koreans, and Japanese (Rushton & Jensen, 2005). It falls off as one moves outward from the core area of East Asia, being lower even among the nearby and closely related natives of Mongolia (Lynn, 2007). This ‘IQ plateau’ must therefore have a relatively recent origin, certainly after the advent of agriculture and probably after the rise of State-pacified societies—where most people expected to succeed through work and trade, and not loot and plunder.

Is this ‘IQ plateau’ due to cultural and family values that are specific to East Asian societies? Not likely. Higher mean IQ is observed in East Asian individuals who were adopted at an early age into white American or European families (Clark & Hanisee, 1982; Frydman & Lynn, 1989; Winick, Meyer, & Harris, 1975). It also correlates with better performance at more fundamental mental tasks, like reaction times (Rushton & Jensen, 2005). It seems to be genetically determined.

What caused this genetic evolution? In a recent article, Ron Unz attributes it to the social dynamics of an agrarian society where both land and women were scarce. With limited prospects for starting a family, the lowest strata of society were continually dying out and being replaced by downwardly mobile individuals from the highest strata: 

 […] only the wealthier families of a Chinese village could afford the costs associated with obtaining wives for their sons, with female infanticide and other factors regularly ensuring up to a 15 percent shortfall in the number of available women. Thus, the poorest village strata usually failed to reproduce at all, while poverty and malnourishment also tended to lower fertility and raise infant mortality as one moved downward along the economic gradient. At the same time, the wealthiest villagers sometimes could afford multiple wives or concubines and regularly produced much larger numbers of surviving offspring. Each generation, the poorest disappeared, the less affluent failed to replenish their numbers, and all those lower rungs on the economic ladder were filled by the downwardly mobile children of the fecund wealthy. (Unz, 2013)

In this Hobbesian world, reproductive success went to those with the most business acumen:

The members of a successful family could maintain their economic position over time only if in each generation large amounts of additional wealth were extracted from their land and their neighbors through high intelligence, sharp business sense, hard work, and great diligence. The penalty for major business miscalculations or lack of sufficient effort was either personal or reproductive extinction. (Unz, 2013)

Another factor may have been the imperial examination: “in China the proud family traditions would boast generations of top-scoring test-takers, along with the important government positions that they had received as a result.” But Unz later backs off from this possible cause, noting that only one percent of the population attained the top rank of chin-shih or the lesser rank of chu-jen—too small a percentage to have much evolutionary impact. True, but those two ranks were only the top of a much larger population pyramid. Success at a lower level, such as at the district or provincial levels, still brought some benefits and prestige, and the beneficiaries were a much larger pool of people (Frost, 2011).

Parallels to Clark’s model

All of this sounds much like the model that Gregory Clark put forward to describe the demographic, behavioral and, perhaps, genetic evolution of the English people. According to this model, the English middle class expanded slowly but steadily from the 12th century onward, thereby gradually raising the population mean for predispositions to non-violence, pleasure deferment, and other future-oriented behavior. Although this social class was initially very small in medieval England, its descendants grew in number and gradually replaced the lower classes through downward mobility. By the 1800s, its lineages accounted for most of the English population (Clark, 2007).

Did Ron Unz steal his idea from Gregory Clark? A casual reader might think so. Buried in the footnotes, however, is a mention of a similar paper that a younger Ron Unz had written back in 1983 while a student at Harvard. But at that time few people were thinking along the same lines. In the history of ideas, Ron’s experience is depressingly similar to that of Patrick Matthew, the Scottish scholar who developed a theory of evolution by natural selection a quarter century before the publication of Darwin’s On the Origin of Species.

Let’s hope this article will give Ron a second hearing in the court of academic opinion. Let’s also hope his article will inspire further research, particularly by Chinese geneticists, historians, and social scientists.

Clark, E.A., and J. Hanisee. (1982). Intellectual and adaptive performance of Asian children in adoptive American settings. Developmental Psychology, 18, 595–599.

Clark, G. (2007). A Farewell to Alms. A Brief Economic History of the World, Princeton University Press, Princeton and Oxford

Frost, P. (2011). East Asian intelligence, Evo and Proud, February 18

Frydman, M., and R. Lynn. (1989). The intelligence of Korean children adopted in Belgium. Personality and Individual Differences, 10, 1323–1326.

Lynn, R. (2007). IQ of Mongolians, Mankind Quarterly, 47, 91-97.

Rushton, J.P. and A.R. Jensen. (2005). Thirty years of research on race differences in cognitive ability, Psychology, Public Policy, and Law, 11, 235-294.

Unz, R. (2013). How Social Darwinism made modern China, The American Conservative, March 11

Unz, R. (1983). Preliminary notes on the possible sociobiological implications of the rural Chinese political economy, unpublished paper.

Winick, M., K.K. Meyer, and R.C. Harris. (1975, December 19). Malnutrition and environmental enrichment by early adoption. Science, 190, 1173–1175.

Saturday, March 9, 2013

Low-hanging fruit?

Labrador retriever running an obstacle course. Can dog intelligence shed light on human intelligence? (source)

My last post described a Chinese project to identify the many genes that contribute to normal variation in human intelligence. If successful, it will simply demonstrate what we already know, i.e., genes are largely responsible for the differences in intelligence we see among normal individuals. 

We know this from intelligence testing, particularly from studies on IQ differences between twins. This evidence, however, has been largely discredited in the eyes of many people, particularly those who act as gatekeepers in the halls of academia. As one scholar told me:

A key problem is funding. Intellectuals on today’s review panels 'came to consciousness' in a climate when intelligence testing was thought to be wrong and invalid. Very few scientists are open to new ideas […] So it often takes a generational turn-over before there is a swing back to a fresh look at intelligence.

I doubt things will change much when the old guard dies off. In some ways, the academic environment was more open-minded two decades ago, when there were still people, often in key positions, who had entered academia before the 1960s. Change will probably come when new evidence manages to bypass the gatekeepers, and this will most likely happen where the marketplace of ideas is less controlled, like in China. Yes, the same country we like to scold for not being sufficiently free and democratic.

What other new evidence could bring change? This question led me to ask the h-bd discussion list: “If you had access to sufficient funding, equipment, and trained personnel, what kind of research project would you like to do or see done?”

A behavioral geneticist suggested the following projects:

1) Investigate individual differences in cognitive abilities in other animal models. a) create a reliable scale. b) establish whether a g factor emerges in other mammals. c) find out the correlates of such a g factor (phenotypic and genetic)- which would be uncontaminated by SES and therefore lay to rest many controversies that arise in humans studies. [Disclaimer, I have started on this with dogs (60 dogs, all one breed, all farm living and am actively seeking funding to continue the project].

2) Investigate the correlates (particularly fitness-relevant correlates of intelligence in populations of hunter-gatherers. Not to examine mean differences between populations - but to test evolutionary hypotheses. Is intelligence associated with offspring number? Social status? Health? Life expectancy? We do not know the fitness optima for intelligence in any human population.

As for myself, I would want to determine whether the Visual Word Form Area is a product of nature or nurture. This could be done by following the same methodology that Zhu et al. (2009) used to prove that our ability to recognize faces is largely hardwired.  If the same is true, or even partly true, for our ability to recognize strings of letters, i.e., words, we would have a compelling argument for gene-culture co-evolution.

I would also want to see whether Tay-Sachs carriers, i.e., heterozygotes, really do have a higher mean intelligence than people without this allele (Frost, 2011). Such a study would be a cinch to do, yet no one has bothered. How come?

Finally, as with hbd* chick, my eyes glaze over when discussion focuses too long on IQ or SAT scores. We need to go beyond intelligence and look at genetic differences that may underlie variation in personality traits, regulation of emotions, time orientation, and so forth. There is more to being human than just intelligence.


Frost, P. (2011) Five years later … still no study, February 4, Evo and Proud.

Zhu, Q., Y. Song, S. Hu, X. Li, M. Tian, Z. Zhen, Q. Dong, N. Kanwisher, and J. Liu. (2009). Heritability of the specific cognitive ability of face perception, Current Biology, 20, 137-142.

Saturday, March 2, 2013

It's not because research is cheaper there

Robert Plomin on the genetics of various mental traits (source)

A Chinese research team is looking for genes that explain why IQ is higher in some people and lower in others:

Studies show that at least half of the variation in intelligence quotient, or IQ, is inherited. But while scientists have identified some genes that can significantly lower IQ—in people afflicted with mental retardation, for example—truly important genes that affect normal IQ variation have yet to be pinned down.

The Hong Kong researchers hope to crack the problem by comparing the genomes of super-high-IQ individuals with the genomes of people drawn from the general population. By studying the variation in the two groups, they hope to isolate some of the hereditary factors behind IQ. (Naik, 2013)

The head of the team, Zhao Bowen, believes this question has not been resolved because it is too controversial. “People have chosen to ignore the genetics of intelligence for a long time," said Mr. Zhao, who hopes to publish his team's initial findings this summer. "People believe it's a controversial topic, especially in the West. That's not the case in China" (Naik, 2013).

Perhaps. But there is another reason: the apparently large number of genes involved and the relatively small effects of each one. This was the conclusion of Robert Plomin, a behavioral geneticist at the Institute of Psychiatry in London:

Failing to find genes for intelligence has, in itself, been very instructive for Plomin. Twin studies continue to persuade him that the genes exist. “There is ultimately DNA variation responsible for it,” he says. But each of the variations detected so far only makes a tiny contribution to differences in intelligence. “I think nobody thought that the biggest effects would account for less than 1 percent,” Plomin points out. 

That means that there must be hundreds—perhaps thousands—of genes that together produce the full range of gene-based variation in intelligence. (Zimmer, 2008)

This should be no surprise. Natural selection doesn’t act on genes, at least not directly. It acts on phenotypes—the flesh-and-blood outcomes of genes. Selection for intelligence will thus affect any gene that has some kind of intelligence-boosting effect.  This point has been made by Linda Gottfredson, a psychology professor at the University of Delaware:

[...] within-group ('individual") differences in intelligence will involve 1000s of genes of small effect, so we can expect that for between-group differences too. Many of the genes will not be specific to intelligence per se but influence broad physiological processes that affect brain structure and function. This would include cardiovascular fitness and much more. (Go exercise, guys!)

I read that perhaps half our genes are expressed in the brain. If half of our segregating genes are too (the 0.1% on which humans are estimated to differ), that's still 1.5 million base pairs or "SNPs" (of 3 billion total).

This indicates the challenge, even if we ignore other important genomic differences (e.g., number of times a given segment of the chromosome is repeated, like a stutter).

[...] This is not to say, of course, that we can't pin down heritabilities for various mean group differences (we could right now if researchers were willing) or that we won't be able to identify numbers or classes of genes on which groups differ most. But it's looking unlikely that we'll be able to pinpoint a list of specific genes that explain much of the normal variation in g, either within or between groups. (Gottfredson, 2013)

Interestingly, Robert Plomin is mentioned as one of the people involved in the Chinese project. Has this research been offshored to a country where the intellectual climate is less restrictive? In addition, since Plomin is aware of the limitations of this kind of study, he might know something that the rest of us don’t. Perhaps among the many genes with small effects there are a few with big effects …


Gottfredon, L. (2013). H-bd discussion list, February 22, 2013

Naik, G. (2013). A genetic code for genius, The Wall Street Journal, February 15

Zimmer, C. (2008). The search for intelligence. Scientific American, October, pp. 68-75.