Tyler Cowen, Brad DeLong and Greg Clark discuss A Farewell to Alms in a seminar from three or four years ago. Thanks to Jason Collins for the link.
I liked Tyler's overview (@36min), which emphasizes that culture, genes and institutions all affect economic growth. He lists of order 10 factors (17!) that impact the industrial revolution, and notes that we have only one historical data point. (To be more accurate we probably have a few, but certainly not enough.) Therefore there must be many models consistent with the facts. (This is of course the fundamental problem for economics and social science, and why progress is so hard.) My review of Clark's book made some similar points. In noting that Clark's ideas are sometimes too simplistic, we should keep in mind he is a primarily an empiricist (economic historian) not a theoretician. He's the guy who pored over ancient British records to obtain demographic data.
DeLong discusses population genetics @31min. Jason recapitulates the argument. My comment on the post (typos corrected) is below.
Brad’s calculation is a bit unrealistic. Most traits are controlled by large numbers of genes and there is a huge amount of extant variation, even within families. No new mutations or special “patience genes" are required for evolutionary change.
A more realistic calculation, that takes into account heritabilities less than one, limited correlation between phenotype and reproduction rate, etc. leads to about 1000 years as the fastest timescale for shift in population mean of about one standard deviation. There has been plenty of time since the dawn of civilization or of agriculture for humans to have changed significantly. A few hundred years is probably not enough time except perhaps in some exceptional cases of really strong selection. I doubt Clark is right that the industrial revolution is primarily a consequence of selection driven pressure in England, although I agree that the British today are probably quite different from their ancestors one or a few thousand years ago.
Apologies for typos — getting used to an iPad.
Clark responds to a question about Guns, Germs and Steel @59min. Pomeranz and Gunder Frank @1:03. Clark returns to more realistic genetic models @1:09. Clark's interest in the heritability of future time preference was stimulated by observations of his three children. Discussion heats up @1:13 -- Brad hews the extreme environmental line whereas Tyler is in the middle. @1:17 Brad reveals again some misunderstanding of population genetics.