Cultural evolution can be a controversial topic. When one thinks about evolution it is natural to think about variation and change in the rather straightforward anatomical traits that one can visually assess or the more complex and discrete traits found at the level of the genome. But behaviors, beliefs, attitudes, and the like are no less phenotypes than one's hair or eye color, and they are, for the most part, heritable (there are some curious exceptions, such as celibacy). For some reason the academic interest in the evolution of behaviors, beliefs, attitudes, sometimes classified under the rubric of "cultural evolution", has tended to center in the field of philosophy of biology: one finds few working biologists who specialize in it, and only a handful of sociologists and anthropologists, historians, and economists. This is unfortunate, because it is an empirical discipline in the end, and it needs some folks besides philosophers doing some work if it is to really take off.
The field took a hit in the early days that has not helped it much since. When Edward Osborne Wilson published his Sociobiology: A New Synthesis in 1975 it caused something of a stir among both philosophers, biologists, and sociologists, some of whom saw his interpretation of the interaction between biological traits and human behavior as a thinly-veiled neo-fascism on the rise. That was, of course, a silly idea, but the damage was done, and sociobiology was often viewed with some suspicion during the late 1970s and the 1980s.
Now Gregory Clark, an economic historian at the University of California, Davis, has a new book forthcoming from Princeton University Press (A Farewell to Alms, due out next month) that seems situated to cause a similar stir, though thankfully without the charges of neo-fascism. According to Clark, the growth in affluence that was witnessed by countries where the Industrial Revolution had its greatest impact was a consequence of cultural evolution. That is, whereas historians and economists ordinarily trace the effects of such things as the Industrial Revolution to the institutions and practices that underlie them, Clark wants to trace the whole kit and caboodle to fundamental changes in human behavior that he thinks were consequences of cultural evolution.
In particular, he notes that technological change often increases the capacity of humans to feed and take care of themselves, but often the technological advantage is soon swamped by a "Malthusian trap" in which the population expands in such a way that the overall affluence of the people is not increased in any tangible way. What happened on the eve of the Industrial Revolution was quite interesting. From 1200 to 1800 in England the population went through several evolutionary bottlenecks, such as the Black Death, where the population was suddenly and severely reduced. Casualties were mostly in the cities, and so immigration from the countryside was required to replenish the inhabitants of the large, industrial centers. These people, in turn, came to be better off than they had been when living in the country, and as they grew richer and better able to care for themselves and their children, it was their offspring that mostly survived the various bottlenecks. By the late 1700s the population of England was largely derived from the economic upper classes of the Medieval period. By studying documents from the period from 1200-1800, Clark shows how work hours steadily increased, literacy and numeracy levels rose, and the rate of interpersonal violence dropped. More importantly came a concomitant preference for saving over consumption. These behavioral traits slowly became embedded in the English population, and they stoked the furnace of the Industrial Revolution.
According to Clark, the peoples of industrialized nations such as England are substantially different from the peoples of hunter-gatherer societies as a consequence of this behavioral evolution in which the more affluent out reproduce their poorer neighbors, thus insuring the survival of the behavioral traits that gave rise to their affluence in the first place and, as a result, helping future generations to survive population bottlenecks. It is a fascinating hypothesis, and I am eagerly awaiting the publication of the book. Those who would like to learn more should check out this story at the New York Times.