Gregory Clark offers a provocative thesis in Farewell to Alms that human nature changed to escape from a malthusian cycle. Prior to industrialism, any improvement in productivity was nullified by an increase in population. This kept humanity trapped at the same level of wealth throughout the Middle Ages and doomed men to face frequent bouts of famine.

Around 1750s to the 1850s, there was a series of major behavioral changes that allowed Industrialism to take place. Clark argues that this is due to a mixture of cultural and biological evolution.

Robert Fogel wrote a similar economic history recently (The Escape from Hunger). Industrialism and the Second Agricultural Revolution was a paradigmatic shift in human history. There have been few good explainations as to why it occurred. Clark offers his hypothesis.

NY Times (via Gene Expression)

Gregory Clark, an economic historian at the University of California, Davis, believes that the Industrial Revolution — the surge in economic growth that occurred first in England around 1800 — occurred because of a change in the nature of the human population. The change was one in which people gradually developed the strange new behaviors required to make a modern economy work. The middle-class values of nonviolence, literacy, long working hours and a willingness to save emerged only recently in human history, Dr. Clark argues.

Because they grew more common in the centuries before 1800, whether by cultural transmission or evolutionary adaptation, the English population at last became productive enough to escape from poverty, followed quickly by other countries with the same long agrarian past.

Here’s the meat of his theory. Mankind escaped from Malthusianism due to behavior changes, not technological innovations. The new men of industrialism were superior at abstract thought, were more patient, and believed in delayed gratification. This allowed the revolutions in economics.

The basis of Dr. Clark’s work is his recovery of data from which he can reconstruct many features of the English economy from 1200 to 1800. From this data, he shows, far more clearly than has been possible before, that the economy was locked in a Malthusian trap — each time new technology increased the efficiency of production a little, the population grew, the extra mouths ate up the surplus, and average income fell back to its former level.

This income was pitifully low in terms of the amount of wheat it could buy. By 1790, the average person’s consumption in England was still just 2,322 calories a day, with the poor eating a mere 1,508. Living hunter-gatherer societies enjoy diets of 2,300 calories or more.

Clark uncovered a counterintuitive fact in his research. Historians assumed that new waves of peasants replaced losses in congested cities. The assumption may have been in error.

Generation after generation, the rich had more surviving children than the poor, his research showed. That meant there must have been constant downward social mobility as the poor failed to reproduce themselves and the progeny of the rich took over their occupations. “The modern population of the English is largely descended from the economic upper classes of the Middle Ages,” he concluded.

Here, he suggests that biological evolution may have played a role. I’m sure this will be the controversial part. I’m skeptical based on this evidence alone, so I’ll have to check out all his research. What he describes could either be genetic or cultural memes passed through families. Either could explain the change in habits in the lower and middle classes.

The fact that the modern Middle Class are direct genetic descendants of the old Upper Class is interesting on its own merits.