From an article about Gregory Clark's A Farewell to Alms:
Historians used to accept changes in people's behavior as an explanation for economic events, like Max Weber's thesis linking the rise of capitalism with Protestantism. But most have now swung to the economists' view that all people are alike and will respond in the same way to the same incentives. Hence they seek to explain events like the Industrial Revolution in terms of changes in institutions, not people.
Dr Clark, though, argues that institutions and incentives have been much the same all along and explain very little, which is why there is so little agreement on the causes of the Industrial Revolution. He believes natural selection - genetic transmission of capitalist values - is the answer. To me this sounds far-fetched and unnecessary, though I haven't read the evidence that Dr Clark has compiled. I don't often find myself in the position of agreeing with "the economists' view", but I do think incentives are critical. Looking at the failure of certain countries to develop, I can't point to any lack of resourcefulness on the part of their citizens. More compelling to me is how this simple question would be answered: "if people work hard, what is the chance that they will be allowed to keep most of their earnings?" For most societies in the past, and for many today in the poor world, that probability has been too low to make capitalism worthwhile.