Friday, February 25, 2011

More on Clark's model

Upper-caste Indians. Clark’s model works poorly in State societies where class divisions are rigid and where different classes operate according to very different rules.

In my last post, I discussed Ron Unz’s essay on selection for intelligence in East Asian societies. This paper, as its own author points out, makes the same point that Gregory Clark has made with respect to England.

In sum, State societies create a new environment of natural selection. The Big Man goes from hero to zero (unless he is part of the tiny ruling elite). For most people, the road to success is the market economy, and such success requires a special behavioral package:

1. abandonment of violence as a means to resolve disputes and increase personal wealth;
2. ability to plan ahead and save for tomorrow
3. general trade-related skills, notably numerical and text processing

Over time, economic success would have translated into demographic success. This nascent middle class would have grown in number, with downwardly mobile descendents spreading into the lower classes and gradually replacing them. Eventually, they and their heritable characteristics would have come to dominate the entire gene pool.

The problem with this argument is that many State societies do not seem to have followed this route. As Steve Sailer notes, “Ancient Egypt would seem like a similarly "orderly, stable, and advanced" peasant society, but the outcomes don't seem very similar” [to those of China and England].

Well, Egypt was not a closed gene pool. Its middle class may very well have been demographically successful, and their descendents may very well have spread downward into the lower classes. But that’s where the similarity ends. There was also a steady influx of foreign slaves into the lower classes (and even into the middle and upper classes through concubinage).

But, still, one can think of other examples. What about India? The main problem there would have been the caste system: the effects of natural selection on one caste could not have easily spilled over into the general population. Yes, one could change caste, but it was not an easy option.

To varying degrees, this problem would have happened elsewhere. In addition, rigid class boundaries often coincided with ethnic boundaries, the middle class being dominated by minorities of one sort or another.

What about England? Interestingly, Gregory Clark (2009) does point to social mobility as being a key element of his model. To measure social mobility, he looked at rare surnames from two points in history, 1600 and 1851, and the socioeconomic status of their bearers:

How do the descendants of these two groups look in terms of socioeconomic status by 1851? Surprisingly there seems to be almost complete regression to the mean. Table 9 shows some measures of the socioeconomic status for a sample of adult men of both name groups, taken from the names with the less frequent occurrences. While those descended from the rich show a slightly greater percentage in the top socio-economic groups, that result may well be sampling error. And at the bottom of the socio-economic scale, there are more of the descendants of the rich among “laborers” than there are descendants of the indicted.

… This implies both great downward mobility among the descendants of the rich, and modest upward mobility among the descendants of the indicted.

This can be illustrated with particular names. 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

Thus, lack of social mobility would prevent Clark’s model from working. A related problem is that the lower classes tend to operate according to a different set of rules. A successful ability in a middle-class context might be maladaptive in another context. This is particularly the case where the lower classes are not simply less successful individuals, and where they live under a very different legal and economic regime.

Serfdom comes to mind. In this, England was lucky. The Black Death had greatly weakened serfdom, and the upper classes were unsuccessful in their attempts to re-establish it. The conditions were thus in place for the demographic revolution described by Clark.


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

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

Unz, R. (1980). Preliminary notes on the possible sociobiological implications of the rural Chinese political economy, unpublished paper.


Tod said...

"A successful ability in a middle-class context might be maladaptive in another context"

A big difference between England and China lies in personality, the Chinese are cautious. So maybe in China a man could not afford to make a mistake because Chinese society was a socio/genetic slippery slope where falls in status would be be would be extraordinarily difficult to come back from.

The English have a greater propensity for the demimonde lifestyle. Does that mean that the Englishman who became downwardly mobile had more chance to stage a comeback or that being poor was less lethal than in China for a middle class man ?

Harmonious Jim said...

If there are IQ differences among non-state peoples (eg Amerindians vs Aboriginals), then some process of natural selection must have been happening before, setting the stage for, these later selections.

You say that societies divided into endogamous groups (eg castes), high IQ wont be able to spread. But in Eastern Europe and Russia, the existence of a high IQ commercial group (Jews) didn't stop the peasants having relatively high IQ by world standards.

Anonymous said...

"But in Eastern Europe and Russia, the existence of a high IQ commercial group (Jews) didn't stop the peasants having relatively high IQ by world standards."

I was under the impression that they were only a very small segment of the population up until the last few centuries. Then their ranks exploded due to urban economic success, with a eugenic positive feedback loop. Don't know if this is true though.

Tod said...

Experimental Domestication Of Foxes Yields Clues To Cognitive Evolution

The current National Geographic has an informative article it quotes Hare as saying:-

"They didn't select for a smarter fox but for a nice fox," says Hare. "But they ended up getting a smart fox."

It can't be that simple, can it ?

Peter Frost said...


My impression is that poverty was more lethal in China than in England, but I wouldn't exaggerate the difference.

Until the late 19th century, the urban English poor were a population sink. This is one reason why the English working class began to develop a sense of class consciousness from that time onward. Working class communities became stable multi-generational societies. This was not the case previously.

(second comment) Not necessarily that simple, but you may have put your finger on the main evolutionary pathway. What we call "learning" was originally an infant trait in early hominids. It then became extended into older age groups, much as lactose tolerance became extended in milk-consuming peoples.

Harmonious Jim,

In my opinion, selection for intelligence cannot be packaged into a single theory. There have been many selection pressures acting on this trait.

Tod said...

In 'Civilization the West and the Rest' Ferguson quotes a Chinese scholar as saying that Chinese social scientists now think the Christian moral foundation of social and moral life was the secret of the West's success. Wenzhou where the free market has the most influence has 1,400 churches. A top business leader in Wenzou suggests that an absence of trust was one of the main factors holding China back. However he can now trust his fellow Christians to be honest in their dealings.

Tod said...

Class consciousness came to urban Britain when it ceased to be a population sink for the poor,that makes a lot of sense. And it explains something that puzzled me: why the earliest industrial conflicts happened in Britain.

Barnett in 'The verdict of peace: Britain between her yesterday and the future' has a chapter called 'The psychology of the underdog' about working class communities where old people where known as scabs although the strikes happened generations before).