Monday, August 22, 2022

Diet Drives Height

Individual variation in height, like individual variation in IQ, is strongly influenced by genetics. But, population level variations in height (between populations or over time) is profoundly influenced by environment, rather than genetic legacies. There is a good case to be made that the same is true of IQ.

This paradox is also seen, for example, in modern Japan and South Korea where height is closely correlated with year of birth, with children born later in more economically prosperous times with less food scarcity ending up taller.

This also provides a food production counterpart to the "coal curse" by which regions with particularly great coal resources lagged in later economic development as the natural resource based economy fostered by rich coal resources prevented other forms of economic production from thriving, which mattered when coal became less economically important.
In the late nineteenth century, the North American bison was brought to the brink of extinction in just over a decade. We demonstrate that the loss of the bison had immediate, negative consequences for the Native Americans who relied on them and ultimately resulted in a permanent reversal of fortunes. Once amongst the tallest people in the world, the generations of bison-reliant people born after the slaughter lost their entire height advantage. By the early twentieth century, child mortality was 16 percentage points higher and the probability of reporting an occupation 29.7 percentage points lower in bison nations compared to nations that were never reliant on the bison. Throughout the latter half of the twentieth century and into the present, income per capita has remained 28 percent lower, on average, for bison nations. This persistent gap cannot be explained by differences in agricultural productivity, self-governance, or application of the Dawes Act. We provide evidence that this historical shock altered the dynamic path of development for formerly bison-reliant nations. We demonstrate that limited access to credit constrained the ability of bison nations to adjust through re-specialization and migration.
Donn. L. Feir, Rob Gillezeau & Maggie E.C. Jones, "The Slaughter of the Bison and Reversal of Fortunes on the Great Plains" NBER Working Paper 30368 (August 2022), DOI 10.3386/w30368

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