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Uncommon Knowledge

Why kids fail the marshmallow test

Be a man: tell the truth

Higher levels of testosterone have been implicated in some negative qualities associated with men, such as impaired empathy. Recent research, though, is showing some upsides of the same hormone; now, a new study finds that testosterone inhibits lying. Men were given either testosterone or a placebo and were later asked to roll a six-sided die in private, and whatever number the men reported rolling would determine their payoff for the experiment. Men with higher testosterone reported they’d scored payoffs far closer to the rate of probability. While men who were administered the placebo reported rolling the highest payoff 62% of the time, those who were administered testosterone reported rolling the highest payoff just 35% of the time.

Wibral, M. et al., “Testosterone Administration Reduces Lying in Men,” PLoS ONE (October 2012).

Ignoring the poor vote

The Democratic Party has long lamented the lower turnout of poor voters relative to affluent voters. But new research from a political scientist at Baylor University suggests that once candidates get to office, it’s a lost cause anyway. He analyzed “the extent to which the opinions of low and high income constituents predict their Senators’ roll call voting given different relative levels of voter turnout across the American states.” His stark conclusion: “Regardless of whether the rich/poor voter turnout gap is large or small, the opinions of the wealthy strongly predict their Senators’ voting behavior while the opinions of the poor do not.”

Flavin, P., “Does Higher Voter Turnout among the Poor Lead to More Equal Policy
Representation?” Social Science Journal

Why kids fail the marshmallow test

One of the most famous tests of people’s ability to delay gratification is the “marshmallow test,” in which children are seated in front of a marshmallow and told they’ll get an extra one if they wait to eat the one in front of them. Success on this test has been correlated with success in later life, and poor children tend to do worse on such tests. Why? A new study suggests an answer: The unstable environment associated with poverty makes delaying gratification harder. Before taking the marshmallow test, children worked on an art project where the supervisor promised to bring better supplies and either was or wasn’t able to deliver. After experiencing the reliable supervisor, children held out much longer in the marshmallow
test than after experiencing the unreliable

Kidd, C. et al., “Rational Snacking: Young Children’s Decision-Making on the Marshmallow Task Is Moderated by Beliefs about Environmental Reliability,” Cognition (forthcoming).

Depression: not so contagious

You don’t need a scientific study to tell you that emotions can be contagious. But many people worry—and some research has found evidence—that mental health problems are also contagious. A new study should assuage some of that concern. College freshmen, who had been randomly assigned roommates, were surveyed both before the start and toward the end of the academic year. While mental health worsened somewhat during the year—as one might expect in a stressful new environment—it wasn’t very contagious between roommates, even if they spent more time together. In fact, among women, having a close relationship with a depressed roommate appeared to reduce one’s own depression. A different pattern was true for men, in that having a distant relationship with a depressed roommate appeared to increase one’s own depression.

Eisenberg, D. et al., “Social Contagion of Mental Health: Evidence from College Roommates,” Health Economics (forthcoming).

What the North has to answer for

Since 1970, the percentage of Americans in prison has skyrocketed; the incarceration rate is especially pronounced among blacks. Though it’s often assumed that the racial disparity came along with the surge in incarceration, a recent study by a sociologist at Harvard suggests that the disparity originated earlier, with the emigration of blacks from the South. Not only was the racial disparity in incarceration higher in the North to begin with, but it rose sharply in the North after 1880, even while dropping sharply in the South after 1900. What exacerbated the racial disparity in the North was the fact that blacks were competing with lower-class immigrants from Europe, many of whom—particularly the Irish—had come to dominate law enforcement and were looking for any excuse to arrest blacks. In a sense, the Irish—who, ironically, had gotten a reputation as troublemakers when they first immigrated—traded places with blacks. “As the incarceration rate of Irish immigrants and their children in Great Migration states declined from 245 to 158 people per 100,000 between 1880 and 1950, the nonwhite incarceration rate leapt from 203 to 594.”

Muller, C., “Northward Migration and the Rise of Racial Disparity in American Incarceration, 1880–1950,” American Journal of Sociology (September 2012).


Kevin Lewis is an Ideas columnist. He can be reached at kevin.lewis.ideas@gmail.com.