Following the Consilience Conference and some suggestions for additions to my reading list, I have been convinced to read some more work by Robert Boyd and Peter Richerson. I’ve started with The Origin and Evolution of Cultures.
One quote in the introduction caught my eye:
[A]cquiring adaptive information from others also opens a portal into people’s brains through which maladaptive ideas can enter—ideas whose content makes them more likely to spread, but do not increase the genetic fitness of their bearers. Such ideas can spread because they are not transmitted as genes are. For example, in the modern world, beliefs that increase the chance of becoming an educated professional can spread even if they limit reproductive success because educated professionals have high status and thus may likely be emulated. Professionals who are childless can succeed culturally as long as they have an important influence on the beliefs and goals of their students, employees, or subordinates. The spread of such maladaptive ideas is a predictable by-product of cultural transmission.
While I might characterise the maladaptation differently – it is not being a professional in itself that limits reproductive success – this approach contrasts with the economic explanation. Economists usually frame the fertility decision as a rational quality-quantity trade-off. In addition to the usual economic assumption of rationality concerning the pursuit of an objective, there is also an assumption that the objective itself (fitness in a biological sense) is rationally chosen. There is no maladaptation, and I suspect this is the cause of some of the difficulty the economic approach to the problem has faced.