In two recent posts I examined the causative mechanisms underlying Ashraf and Galor’s hypothesis linking genetic diversity to economic growth (innovation and conflict). In those posts, I avoided examining whether genetic diversity could be considered a proxy of phenotypic diversity unrelated to that genetic diversity (such as language). Part of the reason for this is that Ashraf and Galor do not indicate in their paper or web appendix that they intended to use genetic diversity as a proxy in this way.

Being a naturalist in the Victorian era was a different exercise to today. From Darwin’s The Descent of Man: Many kinds of monkeys have a strong taste for tea, coffee, and spiritous liquors: they will also, as I have myself seen, smoke tobacco with pleasure. (6. The same tastes are common to some animals much lower in the scale. Mr. A. Nichols informs me that he kept in Queensland, in Australia, three individuals of the Phaseolarctus cinereus [koalas]; and that, without having been taught in any way, they acquired a strong taste for rum, and for smoking tobacco.

Links this week: A good profile of Joe Henrich and WEIRD people. Nassim Taleb and Daniel Kahneman discuss antifragility. A gene for cooperation in response to punishment. I’ve uploaded an updated version of my working paper Conspicuous Consumption, Sexual Selection and Economic Growth. There are no earth-shattering changes, but we’ve simplified the second model and generally sharpened it up.

Should Ashraf and Galor’s paper The ‘Out of Africa’ Hypothesis, Human Genetic Diversity, and Comparative Economic Development have been published? The major critique about whether the paper should have been published comes from the conclusion of an article in Current Anthropology: Social scientists seeking to explain economic behavior through genetics must exercise particular caution. As Benjamin et al. (2012:656) point out, “researchers in this field hold a special responsibility to try to accurately inform the media and the public about the limitations of the science,” especially in studies intended for “social-scientific interventions” (Benjamin 2010:1).

James Flynn of Flynn effect fame has a relatively new book out, Are We Getting Smarter? I have found Flynn’s earlier books to be easy but not great reads, and this book followed that pattern. However, reading them is worthwhile as they tend to provide a comprehensive update on the latest in IQ testing from around the globe. Flynn is also not afraid to throw in some interesting arguments. The question in the title of the book has two elements.

Links this week: A week ago I posted about a piece in the Economist on Greg Clark’s work using surnames to estimate social mobility. A debate followed the Economist article, with contributions by Miles Corak, Fransicso Ferreira, Greg Clark (and again), and Jason Long. All are worth reading. Jonathan Last notes three issues that he would include in a second edition of What to Expect When No One’s Expecting: America’s Coming Demographic Disaster.

Ashraf and Galor’s hypothesis linking genetic diversity to economic growth has two limbs. The first, which I posted about last week, is that genetic diversity pushes out the production possibility frontier through increasing the range of traits in the population for developing and implementing new technologies. The second, the subject of today’s post, is that genetic diversity decreases trust and cooperation between people, increasing social disorder and conflict. The measure of genetic diversity used by Ashraf and Galor is expected heterozygosity, which is a measure of the probability that two people selected from the population will have the same allele (variety of a gene), averaged across all measured genes.

I am re-reading Fisher’s The Genetical Theory of Natural Selection and was reminded of this passage that predates modern economic arguments about the evolution of the rate of time preference by over 50 years. For those who want to follow the maths, m is the Malthusian parameter (the relative rate of increase or decrease of a population), lx is the number living to age x, and bx is the rate of reproduction at age x:

Links this week: Matt Zimmerman of Biased Transmission reviews Ashraf and Galor’s theory of genetic diversity and economic development. He points out that the hypothesis can explain any observed pattern in the data. I recommend subscribing to Matt’s feed. Jason Antrosio takes on Jared Diamond’s arguments about violence in hunter-gatherer societies. An excellent read. David Sloan Wilson provides another critique of a straw man version of the invisible hand.

The Economist reports on Greg Clark’s work using surnames to track social mobility. I have posted about this work before, but The Economist piece makes an important point. When tracking mobility across generations, you cannot simply extrapolate the results of a single generation into the future. Corak’s work draws on recent studies that compare income levels between just two generations: fathers and sons. That is out of necessity; good data covering three or more generations are scarce.