Industrial revolution linked to evolution - Economics

USA Today (Society for the Advancement of Education), August, 2003

It took an evolutionary leap in the human species to help trigger the change from centuries of economic stagnation to a state of sustained economic growth, according to the first theory that integrates evolutionary biology and economics. "Until now, economic growth theory did not have implications for evolutionary biology, and evolutionary biology did not have implications for economic growth," maintains Oded Galor, professor of economics, Brown University, Providence, R.I., who co-authored this new theory with Omer Moav of the Hebrew University of Jerusalem. "The struggle for survival that had characterized most of human existence stimulated a process of natural selection and generated an evolutionary advantage to human traits that were complementary to the growth process, triggering the takeoff from an epoch of stagnation to sustained economic growth," they note.

The evolution of the human brain in the transition to Homo sapiens "increased the evolutionarily optimal investment in offspring's quality," asserts Galor. "This was due to the complementary relationship between brain capacity and the return to investment in human capital." The process gave an evolutionary advantage to people who had higher valuation toward offspring's quality. "The subsequently increased prevalence of this genetic trait in the population ultimately permitted the Industrial Revolution to trigger a transition to a state of sustained economic growth."

The critical natural selection that occurred prior to the Industrial Revolution involved the fundamental tradeoff between child-caring and child-rearing. The "epoch of stagnation" gave an evolutionary advantage to a higher-quality smaller family rather than to lower-quality larger families, Galor contends. "Valuation of quality, through better nourishment and education for children, fed back into technological progress. And as technology advanced, it fed back into more education. Human capital took off. This leap in evolution came to dominate the population as a whole, and centuries of economic stagnation ended."

The researchers attribute acceleration in this evolutionary process to the emergence of the nuclear family that fostered intergenerational links. Prior to the agricultural revolution 10,000 years ago, people lived among hunter-gatherer tribes that tended to share resources more equally. "During this hunter-gatherer period, the absence of direct intergenerational links between parental resources and investment in their offspring delayed the evolutionary advantage of a preference for high-quality children," they theorize.

The theory generates an alternative intriguing prediction, Galor says. "It suggests that during the epoch of stagnation, men who were from a physiological viewpoint moderately fertile (men with a moderate sperm count), and who were therefore induced by nature to invest more in the quality of their offspring had an evolutionary advantage over highly fertile individuals." This would suggest that sperm count has declined in the last several thousand years.