It's well-known that many societies hold lefties in low esteem. In Christian tradition, the devil is generally associated with the left hand; the word sinister comes from the Latin for left, sinistra. Arabs have historically used the right hand for eating and the left for, er, activities at the other end of the alimentary process. More scientifically, left-handedness is related to a number of physiological conditions. Lefties have higher rates of high blood pressure, irritable bowel syndrome, and schizophrenia.
On the other hand, if you'll forgive the inevitable bad pun, left-handedness is also linked with creativity. Leonardo da Vinci was a lefty, as were Michelangelo, Isaac Newton, and Albert Einstein. Psychologists confirm that left-handedness involves different brain function: While right-handed people seem to have better cognitive skills on average, studies find that lefties are more common among the highly talented.
What's the economic effect of left- and right-handedness—who makes more money, lefties or normal people? Thanks to two new studies, one from the United States and another from the United Kingdom, we have some answers. At least as far as earnings are concerned, lefties have been unjustly slurred—if they're men.
There are two reasons to expect lefties to earn less, not more. About 11 percent of the American population is left-handed (with slightly more men than women). Learning and working in a world of machines designed for majority righties, lefties are at a disadvantage. Tools like the screwdriver work well for both. But others, like the scissors and the standard classroom writing desk and the electric food slicer and the band saw—not to mention writing from left to right, with all the smudges and blackened fingers that entails—are explicitly designed for righties. This ought to make lefties less productive. (Hence the basis for Ned Flanders' Leftorium, the fictional store for left-handed people on The Simpsons.) In addition, given the studies showing that lefties are more prone to certain illnesses, they would be expected to spend less time in productive activity and, therefore, to earn less.
But that's not the case. In the new U.S. study, authors Christopher S. Ruebeck of Lafayette College and Joseph E. Harrington and Robert Moffitt of Johns Hopkins University looked at a representative sample of 5,000 men and women in the United States. Across the board, they found no discernible difference between the average hourly earnings, and other characteristics, of left- and right-handed people. Both groups earned an average of $13.20 per hour in 1993. They also had identical average intelligence scores. The British study, by Kevin Denny of University College Dublin and Vincent O'Sullivan of the University of Warwick, looked at about 5,000 people born in 1958 and found modest earnings differences: 5 percent higher pay for male lefties relative to their right-handed counterparts and 5 percent lower pay for female lefties compared to female righties.
What's more noteworthy is that the pay difference appears to increase with college education. In the U.S. study, college graduates overall earned an average of 30 percent more than high-school graduates. And after accounting for other determinants of pay—age, intelligence, marital status, and race and ethnicity—lefties with college education earned 10 to 15 percent more than their right-handed counterparts. (The U.K. study did not look at the effect of college education on the earning power of lefties and righties.)
The identification of two styles of thinking may help explain why college-educated lefties make more. Psychologist Stanley Coren defines "convergent" thinking as "a fairly focused application of existing knowledge and rules to the task of isolating a single correct answer." "Divergent" thinking, by contrast, "moves outward from conventional knowledge into unexplored association." There may be an outsize number of lefty geniuses because lefties are more likely to engage in divergent thinking. In an experiment in which subjects devised uses for pairs of common objects, such as imagining that a stick and a can could together be a birdhouse, lefties on average came up with nearly 30 percent more uses.
But the tendency toward greater aptitude in divergent thinking holds only for male lefties. Psychologists don't know why this is the case. One hypothesis concerns differing levels of fetal testosterone. This is just a possibility: Psychologists agree that the relationship between left- and right-handedness and brain function is still not well-understood. Whatever its cause, though, the male lefty advantage may have an economic effect: The boost in earnings found in the U.S. study was associated with left-handedness only for men. The study found no systematic difference between the pay of women lefties and women righties, regardless of education or other factors.
These results suggest that education and an edge in divergent thinking are a potent mix that put college-educated male lefties on top in the earnings game. Any practical consequences? If your family's college fund runs short, you might send your lefty sons to college and the rest of the brood to trade school. And if you're at a college mixer or alumni reunion looking for a mate with high earning potential, you might keep an eye out for the guy who wears his watch on his right wrist.