Saturday, January 21, 2012

Do classes become castes?

Relative frequencies of surnames of the rich and the poor (common criminals) 1236-1858. In England, there seems to have been much downward mobility among descendants of the medieval rich and some upward mobility among descendants of the medieval poor (Clark, 2010).
H/T to Jason Malloy

Henry Harpending (2012) argues that a meritocracy would become a caste society in a few generations:

Consider free meritocracy in a two-class system, meaning that for each generation anyone in the lower class who has greater merit than someone in the upper class immediately swaps class with them. Mating then occurs at random within class.

[…] Class mobility after the first generation is 30% while after four generations it has declined to 10% and continues to decline after that. The average merit in the two classes is about -1SD in the lower and +1SD in the upper on the original scale, corresponding to IQs of 85 and 115.

[…] after four generations, about 70% of the variance is between classes.

This model, however, contradicts what Clark (2009a) found in his historical study of surnames and social class in England. He first collected rare English surnames that were exclusive in the year 1600 to the rich (as represented by wealthy testators) or to the poor (as represented by common criminals). He then went forward in time to the year 1851 and determined the occupational profile of the same rare surnames:

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.

Between 1600 and 1851, there was apparently great downward mobility among descendants of the rich and modest upward mobility among descendants of the poor. Clark (2010) subsequently found that this regression held true for the entire period stretching from 1236 to 1858 (see above chart).

Why does this outcome diverge so much from the theoretical outcome described above? One reason is the assumption that marriage takes place only within each social class. Yet assortative mating is only a tendency, and exceptions are numerous. In post-medieval England, a widower would likely take a second wife of lower social status because of his disadvantaged position on the marriage market, given the care required for his existing children. It was also accepted for an upper-class man to marry a woman of lower rank, on the condition that she be beautiful. This phenomenon was noted by Darwin:

Many persons are convinced, as it appears to me with justice, that our aristocracy, including under this term all wealthy families in which primogeniture has long prevailed, from having chosen during many generations from all classes the more beautiful women as their wives, have become handsomer, according to the European standard, than the middle classes; yet the middle classes are placed under equally favourable conditions of life for the perfect development of the body. (Darwin, 1936 [1888], p. 892)

Another reason is downward mobility. In England, the upper and middle classes were reproductively more successful than the lower class until the late 19th century. But higher-class families could offer their children only a limited number of occupational slots. A certain proportion thus had to emigrate or move down the social ladder. The lower class was thereby continually replenished by the demographic overflow of the upper and middle classes.

Finally, the word “merit” has different meanings in different contexts. It is never just IQ. In post-medieval England, merit meant a mix of “middle-class” values: thrift, self-control, future time orientation, and rejection of violence as a way to settle disputes (Clark, 2007; Clark, 2009a; Clark, 2009b). In other societies, merit may involve a different mix of predispositions and personality traits, such as ruthlessness and willingness to use violence.

Yet caste societies do exist. How do they come about? The main precondition seems to be not only the existence of social classes, but also a monopoly on certain occupations by each class. In such circumstances, downwardly mobile individuals cannot compete with the existing lower class, since the latter’s livelihood remains off-limits.

Take Japan. That country had a social evolution similar to England’s, i.e., gradual demographic expansion of the middle class and, correspondingly, gradual demographic replacement of the lower classes by downwardly mobile individuals. But the lowest class, the Burakumin, survived because it had a monopoly on occupations that involved taking life or handling dead bodies (e.g., leather working, butchery, undertaking, etc.). The Burakumin thus survive as a remnant of the majority Japanese population that existed several centuries ago.

Stigmatized castes, like the Burakumin, may provide a window into a population’s evolutionary past. Such groups cannot participate in the gene-culture co-evolution of the majority population. Nor do they have much leeway for their own gene-culture co-evolution, since they are rigorously confined to a few occupations.


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

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

Clark, G. (2009b). The domestication of Man: The social implications of Darwin. ArtefaCTos 2(1): 64-80.

Clark, G. (2010). Regression to mediocrity? Surnames and social mobility in England, 1200-2009

Darwin, C. (1936) [1888]. The Descent of Man and Selection in relation to Sex. reprint of 2nd ed., The Modern Library, New York: Random House.

Harpending, H. (2012). Class, Caste, and Genes, West Hunter, January 13


Sean said...

I think there is an analogy with what was once observed in Galapagos Finches. Under unusual environmental conditions they were beginning to form into two subsets one with robust beaks one with gracile beaks. (The average sized beaks were at a disadvantage for obtaining food). For two castes to form wouldn't the intermediate class of society have to be at a disadvantage?

Sean said...

Re the inflow of beautiful women into the upperclass. I don't think that would make upper class men more handsome. Folk wisdom would have it that upper class men are 'chinless wonders'. Steve Sailer had an interesting post about this "Why doesn't evolution get rid of ugly people?"

I would like to make a suggestion for a population that provides a window into Europe,s evolutionary past - the Irish. My grandfather was half Irish. He was a very heavy drinker but never got a hangover (until a stroke at 48). His teeth closed edge to edge, like a Cromagnon's.

Anonymous said...‏

"In cultures that permit men to take multiple wives, the intra-sexual competition that occurs causes greater levels of crime, violence, poverty and gender inequality than in societies that institutionalize and practice monogamous marriage."

"Considered the most comprehensive study of polygamy and the institution of marriage, the study finds significantly higher levels rape, kidnapping, murder, assault, robbery and fraud in polygynous cultures. "

Peter Frost said...


Even Clark was a bit surprised by his findings, given that England is perceived as having a rigid class system.


There would have to be some kind of isolating mechanism. One of the most effective such mechanisms among humans is occupational. If certain occupations are reserved for the lower class, it becomes easier to police the class boundary. A downwardly mobile individual cannot euphemistically call himself "lower middle-class."

With regard to Darwin's observation, it probably matters less to upper-class men if they come to look effeminate because of this sexual selection. Men are judged more on their control of resources than on their beauty.


Interesting study. It makes many points that I and others have made.

chris said...


Ben10 said...

I have a memory recollection of book about a frankish traveler who traveled to England, probably around the 13-14th century. Now, to be able to do that, this traveler must have been from the upper society, nobility or clerical, with plenty of contact with good looking people of frankish ancestry. Still, he reported to the french king how he was stricken by the beautiful and fine traits of the anglosaxons kids he saw in the english cour. I remember he said 'they all look like angelots'.

That doesn't mean frankish kids from the nobility were ugly, but since anglosaxon and frankish nobility share a common germanic ancestry, this point to an accelerated accumulation of neotenic traits in the anglosaxon nobility once they were installed and isolated in England. At the same time the frankish nobility was receiving more diverse genetic influence, latine in particular.

So the english were breeding an upper caste of 'angelots', at least for a while. I am sure it was not intentional but probably through sexual selection, that was the result anyway. Sexual selection during the middle ages was probably extremely strong with all these warfares and extra women available in the upper class and nobility.

soupdoganon said...

"England is perceived as having a rigid class system"

Perhaps the strictness of the English class system in terms of behaviour, dress, accent etc masked the underlying mobility?