Height through the millennia

For the last year or so, I have had sitting in my “to blog” pile a 2004 New Yorker article about the increasing height of Europeans relative to Americans. It has a lot of interesting content. It talks about how height peaked in Europe around 800 AD, before declining through to 1700 (largely associated with the rise of cities), and then commencing an upward climb. It notes how Mexican-American teenagers have now equalled the United States norm, while American Mayan teenagers have gained four inches on Guatemalan Mayan teenagers in around two decades. The overarching point of the article is also interesting, that being the failure of heights to increase in the United States (after screening for issues around immigration, race etc.) since the 1950s while European heights continue to rise.

I’ve delayed putting a post up as I’m still getting my head around a lot of the research in the area, and I’m not sure if the main concern was still current following more recent studies. But some recent events have triggered me to put together this post despite still not being fully across the area. The triggers include some comments following my recent post on obesity (to which those observations on Latin American height directly relate), the death of Robert Fogel, a passage in Marlene Zuk’s Paleofantasy and some comments by James Flynn in Are We Getting Smarter?.  So, here are a few interesting snippets.

Robert Fogel is interviewed in the New Yorker article, including about his work Time on the Cross: The Economics of American Slavery:

Historians had long insisted that slavery was not only inhuman; it was bad business—hungry, brutalized workers made the poorest of farmers. Fogel and Engerman found nearly the opposite to be true: Southern plantations were almost thirty-five per cent more efficient than Northern farms, their analysis showed. Slavery was a cruel and inhuman system, but more so psychologically than physically: to get the most work from their slaves, planters fed and housed them nearly as well as free Northern farmers could feed and house themselves. …

Steckel decided to verify his mentor’s claims by looking at the slaves’ body measurements. He went through more than ten thousand slave manifests—shipboard records kept by traders in the colonies—until he had the heights of some fifty thousand slaves; then he averaged them out by age and sex. The results were startling: adult slaves, Steckel found, were nearly as tall as free whites, and three to five inches taller than the average Africans of the time.

The height study both redeemed and rebuked “Time on the Cross.” Although the adult slaves were clearly well fed, the children were extremely small and malnourished. (To eat, apparently, they had to be old enough to work.) But Fogel was more than willing to stand corrected.

From Zuk’s Paleofantasy, a suggestion that the costs to stature of the shift to agriculture were only transitory while humans adapted to the new diet:

The skeletons of ancient farmers are filled with evidence of tooth decay, iron deficiency anemia, and other disorders. Diamond notes that the Greek and Turkish skeletons from preagricultural sites averaged 5 feet 9 inches in height for men and 5 feet 5 inches for women, but after farming became established, people were much shorter—just 5 feet 3 inches and 5 feet, respectively, by about 5,000 years ago, probably because they were suffering from malnutrition. The teeth from skeletons of Egyptians who died 12,000 years ago, about 1,000 years after their people had shifted from foraging to farming, were rife with signs of malnutrition in the enamel: a whopping 70 percent of them, up from 40 percent before agriculture became widespread.

Then a funny thing happened on the way from the preagricultural Mediterranean to the giant farms of today: people, at least some of them, got healthier, presumably as we adapted to the new way of life and food became more evenly distributed. The collection of skeletons from Egypt also shows that by 4,000 years ago, height had returned to its preagricultural levels, and only 20 percent of the population had telltale signs of poor nutrition in their teeth. Those trying to make the point that agriculture is bad for our bodies generally use skeletal material from immediately after the shift to farming as evidence, but a more long-term view is starting to tell a different story. For example, Timothy Gage of the State University of New York at Albany examined long-term mortality records from around the world, along with the likeliest causes of death, and concluded that life span did not decrease, nor did many diseases increase, after agriculture. Some illnesses doubtless grew worse after humans settled down, but life has had its “nasty, brutish, and short” phases at many points throughout history.

In Are We Getting Smarter? Flynn offers some thoughts on whether height and IQ gains have a common cause in improved nutrition:

The connection between height gains and IQ gains over time is significant only because it may signal nutrition as a common cause. Coupled with the assumption that nutritional gains have affected the lower classes disproportionately, this brings us back to the IQ curve. Wherever height gains persist, presumably nutritional gains persist, and where nutritional gains persist, IQ gains should show the predicted pattern, that is, gains mainly in the lower half of the curve.

This is not always the case. Martonell (1998) evidences that height gains persisted in the Netherlands until children born about 1965. Yet, cohorts born between 1934 and 1964 show massive Raven’s-type gains throughout the whole range of IQs. The French gained in height until at least those born in 1965. Yet, cohorts born between 1931 and 1956 show massive Raven’s gains that were uniform up through the 90th percentile. …

Norway … counts against the posited connection between height gains and IQ gains. The upper classes tend to be taller. Yet, height gains have been larger in the upper half of the height distribution than in the lower half (Sundet, Barlaug, & Torjussen, 2004). This combination, greater height gains in the upper half of the distribution, greater IQ gains in the lower, poses a serious problem. Are there two kinds of enhanced nutrition, one confined to the upper classes that raises height more than it does IQ, the other affecting the lower classes that raises IQ more than it does height?

If the above is of interest, also have a glance at an earlier post of mine on Fogel, which was triggered by a NYT profile in 2011.