The burgeoning enthusiasm for genetic explanations of everything has emerged in economics. In one of the year's best-sellers, A Farewell to Alms, economic historian Gregory Clark argues that it is not changes in institutions but changes in people which determine the course of history. "The triumph of capitalism in the modern world thus may lie as much in our genes as in ideology or rationality," he says.

One of the key questions in economic history is why the Industrial Revolution took place in England. Clark bases his answers on his research into the reproductive success of wealthy Englishmen. After 1250, rich commoners had more surviving children than the rest, and their children, too, had higher-than-average reproductive success. This meant that the distinctive values which had made them prosperous percolated throughout society, eventually leading to Britain's economic take-off in the late 18th century.

What was being inherited was not necessarily intelligence, but a whole spectrum of desirable character traits which turned England into a hugely successful economy, such as non-violence, literacy, long working hours and a willingness to save.