It pays to be right-handed.
According to a recent study published in the Journal of Economic Perspectives, lefties make about 10 to 12 percent less annually than righties. The paper, written by Joshua Goodman, an economist at Harvard's Kennedy School, is the first study to document the income gap between right-handed and left-handed people.
Why the gap? It may have something to do with how left-handedness correlates with other attributes. Goodman found that left-handed people "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 interesting exception, however, is that lefties born to left-handed mothers don't tend to show lower cognitive abilities than righties.
In his research, Goodman analyzed five data sets from the U.S. and the U.K. that all look at how handedness affects cognitive skill and income over a set amount of time. Goodman found that about 11 to 13 percent of the population is left-handed, a finding that prior research supports.
Lefties have historically been marginalized by society. As Goodman points out, during the Middle Ages, left-handed people were "thought to be possessed by the devil." The medieval Jewish philosopher Maimonides said that lefties shouldn't become priests. In 1903, the Italian criminologist Cesare Lombroso wrote, “What is sure... is, that criminals are more often left-handed than honest men, and lunatics are more sensitively left-sided than either of the other two.”
Even the word "left" itself has unpleasant connotations, if you go back to its roots. It's a derivation of the Old English word "lyft," which meant "idle, weak, or useless," according to Goodman's paper.
But today, "left-handedness has come into vogue," Goodman points out, "with modern proponents who argue that left-handedness is overrepresented among highly talented individuals."
After all, three out of the last four presidents have been left-handed, with George W. Bush being the only righty of the group. A bunch of successful people, like Bill Gates and Oprah Winfrey, are also lefties. And there's new research suggesting that left-handed people may be more creative.
There are at least two widely cited studies that suggest there is a greater share of lefties among smart people. A study from 1986 found that lefties are more prevalent among students who got top scores on the SAT, while a study from 1980 found that there was a higher percentage of lefties among gifted elementary school students than among their non-gifted peers.
Goodman's study seems to fly in the face of that. But as Peter Orszag recently pointed out at Bloomberg View, Goodman's research doesn't necessarily debunk the earlier findings.
It is still possible that lefties are disproportionately represented among the very top of the skills distribution; the databases Goodman uses don't contain enough detail about these extremes to say either way. The SAT study, for example, examined those in the top 1 out of 10,000, and IQs above 131 are found only in the top 2 percent of the population.
In other words, among the successful crowd, being left-handed might correlate with certain advantages. But among the rest of us, statistically, it's righties who come out on top.