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Uncommon Knowledge

Tip: Don’t take big tests on high-pollution days!

And more surprising insights from the social sciences


If you’ve weathered applying for college or getting certified in a field, then you know how nerve-racking major tests can be: It feels like one day can change your life forever. A new study suggests it can—and that even circumstances like bad weather can affect us more than we think. In Israel, which experiences sandstorms and also has high-stakes college entrance exams, students who take these exams on days with low air quality suffer statistically significant score reductions. In turn, this pollution penalty affects matriculation and even wages years later, with “the largest effects among boys, better students, and children from higher socio-economic backgrounds.”

Lavy, V. et al., “The Long Run Human Capital and Economic Consequences of High-Stakes Examinations,” National Bureau of Economic Research (October 2014).

Are lefties disabled?

Three out of our last four presidents have been left-handed: Obama, Clinton, and George H.W. Bush. But according to a professor at Harvard, lefthandedness is actually something of a disability in the general population, because of the way “handedness” is connected to differing brain structures: “Lefties have more emotional and behavioral problems, have more learning disabilities such as dyslexia, complete less schooling, and work in occupations requiring less cognitive skill.” (One exception is that “lefties with lefthanded mothers show no cognitive deficits relative to righties.”) These differences would seem to be at the root of historical stereotypes of lefties: “During the Middle Ages, lefthanded writers were thought to be possessed by the Devil, generating the modern sense of the word sinister from sinistra, the Latin word for left. The English word left itself comes from the Old English lyft, meaning idle, weak, or useless.”

Goodman, J., “The Wages of Sinistrality: Handedness, Brain Structure, and Human Capital Accumulation,” Journal of Economic Perspectives (Fall 2014).

Whew: one way the media isn’t biased

As many newspapers, magazines, TV networks, and movie studios have come under the ownership of a few large conglomerates, it has created the risk and perception that media coverage may be biased by corporate conflicts of interest. A new study tests this proposition by comparing movie reviews issued by media outlets owned by News Corp. or Time Warner—which also own movie studios—to movie reviews issued by media outlets without a cross-ownership conflict of interest. The result? Film critics have apparently maintained their independence: “Using a data set of over half a million movie reviews from 1985 to 2010, we find no statistical evidence of media bias due to conflict of interest in either the News Corp. conglomerate or the Time Warner conglomerate.” The researchers also uncovered no evidence of bias among individual reviewers, and no evidence that movies were selectively assigned or ignored.

DellaVigna, S. & Hermle, J., “Does Conflict of Interest Lead to Biased Coverage? Evidence from Movie Reviews,” National Bureau of Economic Research (November 2014).

White female murder victims get the attention

It’s not a pretty fact, but our society seems to treat some murders as worse than others. A study of homicide convictions from a Louisiana parish revealed that the case files of prosecutors were thicker (that is, contained more pages, “indicating more prosecutorial effort in attempting to secure convictions”) and the ultimate sentences more severe when the victim was a white female, even controlling for aggravating factors. Cases with black male victims had the thinnest case files and the lightest sentences.

Pierce, G. et al., “Race and the Construction of Evidence in Homicide Cases,” American Journal of Criminal Justice (December 2014).

Charter schools would help other kids more

Some research has shown that charter schools in Boston have had positive effects on student outcomes. However, a new analysis of charter schools in Boston finds that the effects would have been even better if the schools were getting a full range of applicants: The kids who apply tend not to be the ones who get the biggest boost from the schools. Students who are already better off financially or academically are more likely to apply, but poor and low-achieving students can expect the most benefit. Unless all schools are converted to the charter system, therefore, they may be stuck well below their potential.

Walters, C., “The Demand for Effective Charter Schools,” National Bureau of Economic Research (October 2014).


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