The US goes straight to your hips
Is America’s weight problem an issue of bad genes or bad environment? A new study suggests the latter. Comparing Korean children who were adopted into American families versus European families, the authors found that American-adopted Koreans were significantly more overweight and obese, even controlling for sex, age, adoption age, and education. In fact, the difference in body-mass index between American- and European-adopted Koreans was about the same as the difference in body-mass index between Koreans living in South Korea and North Korea.
Ulijaszek, S. & Schwekendiek, D., “Intercontinental Differences in Overweight of Adopted Koreans in the United States and Europe,” Economics & Human Biology (forthcoming).
Teens love the unknown
Teenagers have a reputation for risk-taking, but they may be getting a bad rap. When presented with a choice between a sure bet and a gamble, adolescents were actually less willing than adults to take the same gamble with known odds. However, in the case of gambles where the exact odds were not known, adolescents were more willing to take the gamble. These differences held up even when controlling for personality, IQ, and socioeconomic status. So teenagers aren’t risk-takers per se; they’re just more willing to venture into the unknown.
Tymula, A. et al., “Adolescents’ Risk-Taking Behavior Is Driven by Tolerance to Ambiguity,” Proceedings of the National Academy of Sciences (forthcoming).
More bad news about pregnancy stress
Poverty that runs in families and neighborhoods is one of society’s most vexing problems. Researchers at Brown University have now pinpointed an unexpected contributor to that problem: stress during pregnancy. They analyzed data on a sample of pregnancies in Boston and Providence from around 50 years ago, including follow-up data with the children. Children whose mothers had high levels of the stress hormone cortisol during pregnancy developed significantly worse health, verbal IQ, and educational attainment. This was true regardless of prenatal cortisol levels experienced by the children’s siblings, and they didn’t appear to be explained by different prenatal or post-natal parenting behavior. Not only did a mother’s lower income and education correlate with higher cortisol during pregnancy, but the negative impact of high cortisol was worse for less educated mothers.
Aizer, A. et al., “Maternal Stress and Child Outcomes: Evidence from Siblings,” National Bureau of Economic Research (September 2012).
Let our economists in!
In the last several decades, many countries around the world have opened to trade—but why these countries and not others? According to an analysis by professors from the business school at Georgetown University, a major factor in the move to free trade has been the presence of American-educated economists. Controlling for economic factors and the amount of democracy, a country was more likely to open up—and to open up to a greater extent—to trade if it had more US-trained Ph.D. economists per million people.
Weymouth, S. & Macpherson, M., “The Social Construction of Policy Reform: Economists and Trade Liberalization around the World,” International Interactions (forthcoming).
Science vs. climate risk?
Many environmentalists assume that scientific ignorance is at the heart of complacency towards climate change. But a recent survey of Americans suggests otherwise. Perceptions of risk from climate change were actually somewhat lower for people with greater scientific and mathematical literacy. Moreover, the political-cultural polarization that we’re familiar with in other issues was also critical to perceptions of risk—whether for climate change or nuclear power—and this polarization was highest for those with the greatest scientific and mathematical literacy.
Kahan, D. et al., “The Polarizing Impact of Science Literacy and Numeracy on Perceived Climate Change Risks,” Nature Climate Change (October 2012).
Kevin Lewis is an Ideas columnist.
He can be reached at