Class, Caste, and Genes

Friday, November 30th, 2012

If there is any substantial heritability of merit, Henry Harpending notes — where merit is whatever leads to class mobility — then mobility ought to turn classes into hereditary castes surprisingly rapidly:

This figure shows an initial population with normally distributed merit. A new merit based class system is imposed such that the two new classes are of equal size. In this free meritocracy everyone with merit exceeding the population mean moves into the upper class and everyone with merit less than the average moves into the lower class. The second panel of the figure shows the resulting merit distributions by class before reproduction and the bottom panel shows the distributions after endogamous reproduction. This model assumes that the reshuffling of genes during reproduction leads to normal distributions in the next generation within classes.

The process continues for several generations. By analogy with IQ the additive heritability of merit is set to 0.6 so there are substantial random environmental effects. The second figure shows the evolution of class differences over four generations or about 100 years in human terms.

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.


  1. Red says:

    Most of the lower class moving themselves up are bastards of the upper class. My great grand father was sired by son of a wealthy businessman who refused to marry his mother. She then married a Swedish farmer before the child was born and they pretended the kid was the farmer’s. They had 11 other children in all and while each was successful in good fields (mechanic, machine shop worker, ect) only my great grandfather and later my grandfather really excelled. My grand father for example went from car mechanic to airline pilot and my father is a college professor. My line is heads and tails above theirs simply because our great, great grand father was a very smart guy and he passed it on to his bastard son’s line for 4 generations.

  2. The fourth doorman of the apocalypse says:

    The problem is that we rarely see a real meritocracy.

    Those at the top try to keep their progeny at the top as well, but regression to the mean means that their progeny are not as good as they are … and over a few generations they slip down the hill into the lower classes.

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