Science and Technology

A human growth spurt as technology advances

By Patricia Cohen (New York Times)
Updated: 2011-05-08 07:50
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A human growth spurt as technology advances

A human growth spurt as technology advances

For nearly three decades, the Nobel Prize-winning economist Robert W. Fogel and a group of colleagues have assiduously researched what the size and shape of the human body say about economic and social changes throughout history. Their research has spawned not only a new branch of historical study but also a provocative theory that technology has sped human evolution in an unprecedented way during the past century.

This month, Cambridge University Press will publish the capstone of this inquiry, "The Changing Body: Health, Nutrition, and Human Development in the Western World Since 1700," just a few weeks shy of Mr. Fogel's 85th birthday. The book sums up the work of dozens of researchers on one of the most ambitious projects undertaken in economic history.

Mr. Fogel and his co-authors, Roderick Floud, Bernard Harris and Sok Chul Hong, maintain that "in most if not quite all parts of the world, the size, shape and longevity of the human body have changed more substantially, and much more rapidly, during the past three centuries than over many previous millennia." What's more, they write, this alteration has come about within a time frame that is "minutely short by the standards of Darwinian evolution."

"The rate of technological and human physiological change in the 20th century has been remarkable," said Mr. Fogel, who is director of the Center for Population Economics at the University of Chicago's business school. "Beyond that, a synergy between the improved technology and physiology is more than the simple addition of the two."

This "technophysio evolution," powered by advances in food production and public health, has so outpaced traditional evolution, the authors argue, that people today stand apart not just from every other species, but from all previous generations of Homo sapiens as well.

"I don't know that there is a bigger story in human history than the improvements in health, which include height, weight, disability and longevity," said Samuel H. Preston, one of the world's leading demographers and a sociologist at the University of Pennsylvania. Without the 20th century's improvements in nutrition, sanitation and medicine, only half of the current American population would be alive today, he said.

In Europe, at the time of the French Revolution, a 30-something Frenchman weighed about 50 kilograms, compared with 77 kilograms now. And in Norway an average 22-year-old man was 14 centimeters taller at the end of the 20th century (179 centimeters) than in the middle of the 18th century (165 centimeters).

Angus Deaton, an economist at Princeton University, says he admires Mr. Fogel's work as well, but he is skeptical about the emphasis on nutrition, as well as about some of the conclusions researchers have inferred from height.

"We don't really understand why African adults and children are so much taller than Indian adults and children, but it can't be their income, because Indians are much richer," he said.

But "The Changing Body" is full of statistical tables and graphs that include the heights of girls in Croatia and Germany; the caloric energy derived from potatoes, fish and wine; and the average annual allowance of grains and meat for widows in Middlesex County, Massachusetts, from 1654 to 1799.

The basic argument is rather simple: that the health and nutrition of pregnant mothers and their children contribute to the strength and longevity of the next generation.

If babies are deprived of sufficient nutrition in the womb and early in life, they will be more fragile and more vulnerable to diseases later on.

These weakened adults will, in turn, produce weaker offspring in a self-reinforcing spiral. The human body is enormously flexible and responsive, Mr. Fogel said, a fact that fills him with confidence that "the trend of larger bodies and longer lives will continue into the future."

The New York Times

(China Daily 05/08/2011 page11)

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