Left-handed people probably shouldn’t compare their pay checks to their right-handed colleagues – unless they want to be disappointed…according to a recent study.

The study published in the Journal of Economic Perspectives shows that lefties make about 10 to 12 percent less annually than righties. The paper was written by Joshua Goodman, who is an economist at Harvard’s Kennedy School.

This is the first study to document the income gap between right-handed and left-handed people.

But why?

Well, 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.”

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.”

One bizarre part of this study is that lefties who are born to left-handed mothers don’t tend to show lower cognitive abilities than righties.

But just because you are left-handed doesn’t mean you won’t be successful or overcome the dominant right-handed society.

Today, “left-handedness has come into vogue,” Goodman says, “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.