Lefties: Fact vs. fiction

This article will ... Look at the research around the question of whether left-handers die earlier. Examine why left-handed athletes might have a competitive advantage. Review the investigations into left-handed people's intelligence versus those that are right-handed.

In a political climate in which a large portion of our country remains deeply divided, it’s important to remember that our differences are our mutual strength. We each bring our unique perspective and abilities to bear to create a more stable—and perhaps, compelling—society.

International Left Handers Day, Aug. 13, reminds us of that.

Indeed, left-handed folks today are widely regarded as more creative and, in some circles, more clever than their right-handed peers … but such was not always the case.

For thousands of years, southpaws were vilified as "unholy,” linked to various learning disabilities, and implicated in a range of behavioral and mental health conditions. (Lefties are still referred to as “sinistral” in the scientific community, a term derived from the Latin word “sinister,” meaning “of the left.”)

As recently as the 1960s, in fact, children who displayed tendencies towards left-handedness in the American public school system were “corrected” and forced to write and eat with their right hand.

That’s now ancient history, but urban legends persist about the 10 percent of our population who prefer to hold a pencil with their left hand.

“Once upon a time left-handedness or left hand usage was associated with being a witch, and that certainly ended badly,” said Chris McManus in an interview, a professor of psychology and medical education at University College London and author of “Right Hand, Left Hand.”

These days, discrimination due to hand preference is rare, he said, “except in some sports where right-handers are discriminated against in favor of the more unusual motor behaviors of left-handers, which can give a strategic advantage.”

Yet, the research community (and society at large) remains fascinated by the environmental and developmental factors that may influence “handedness,” seeking regularly to assign personality traits to one’s dominant hand—not to mention cognitive capacity and health vulnerabilities.

Why, for example, are lefties so few, consistently representing just 10 percent of the population over the last 5,000 years?¹

Might there be a biological advantage to siding with the majority, as professors Daniel Abrams and Mark Panaggio at Northwestern University proposed in their most recent research (An efficient society, they assert, demands a high degree of cooperation, which resulted in a right-handed majority.”)²

Do lefties really die younger than their right-handed peers, and are they more likely to earn a bigger paycheck, as some research seems to suggest?

International Left Handers Day, Aug. 13, marks an excellent occasion to examine fact from fiction, dispel some common myths, and shine a spotlight on the latest research surrounding lefties.

Do left handed people live longer?

Let’s start with the big one.

One of the most widely quoted statistics about left-handed people is that they die, on average, nine years earlier than their right handed peers, a “discovery” published in two reputable science journals in the late 1980s and early 1990s by American psychologists Diane Halpern and Stanley Coren.³

The scientists, seeking to answer the question of whether lefties die earlier, reviewed roughly 1,000 deaths in Southern California and asked family members whether the deceased was right- or left-handed. They found left handers had died at an average age of 66, while righties died at an average of 75.

They also found that left-handers were more than five times as likely to die in industrial and auto accidents—perhaps, they offered, because it is harder for them survive in a right-handed world.

Halpern and Coren also speculated that left-hand dominant people may also succumb to underlying neurological or immune-system diseases, as prior studies had shown were more common in left-handers.

It didn’t take long for noted psychologist Marian Annett, who dedicated her career to researching “handedness” (or hand preference), to debunk the data.

Because elderly people were more likely to be forced to write right-handed as a child, she claimed in 1993, Halpern and Coren’s study was fundamentally flawed.

A random sample of left-handers is likely to be younger than a sample of right handers in the population today, which would also be true of the recently deceased, said Annett.⁴

How about smarts?

The jury is still out as to whether lefties or righties score higher on cognitive tests—way out.

Medical research has consistently shown that the brains of left- and right-handers are wired differently, said McManus, noting that while the parts of the brain that control motor, language and spatial processing skills are used differently, they appear anatomically the same.

And, there does seem to be a larger percentage of lefties among the highly intelligent.

(The web is full of references to high IQ society claiming that 20 percent of its members are left-handed, but a call to the high IQ society revealed they do not track such data.)

Famous lefty super geniuses include Albert Einstein, Aristotle, Charles Darwin, Friedrich Nietzsche, Benjamin Franklin and Sir Isaac Newton, according to lefthandersday.com .

Some suggest that “left-handed genius” stems from being forced to use both sides of the brain more often, allowing lefties to process large amounts of information more readily, according to anythinglefthanded.co.uk , but the evidence to support that claim is largely contradictory.

In fact, the most recent study by Joshua Goodman, an associate professor at the Harvard Kennedy School, found lefties scored about 10 to 12 percent less than righties on “measures of cognitive skill”, even after controlling for health as babies and family background.⁵ (Several studies in the 1970s and 80s linked birth stress to handedness, but more recent reports are less conclusive.)

Looking at five large studies of individuals in the U.S. and United Kingdom, and data on education and employment, Goodman further found lefties also had more behavioral and speech problems and were more likely to have learning disabilities.

Lefties work in more manually intensive occupations than do righties, further suggesting that lefties’ primary labor market disadvantage is cognitive rather than physical,” Goodman writes in his 2014 abstract.

Interestingly, five of the last eight presidents were southpaws: Gerald Ford, Ronald Reagan, George H.W. Bush, Bill Clinton and Barack Obama. Chalk it up to inconclusive evidence.

Lefties are better athletes?

In sports involving hand-eye coordination, it seems, southpaws appear to have an athletic advantage, which explains why the proportion of left-handed elite athletes is notably higher in baseball, boxing, swimming, tennis, fencing and table tennis.

Lefthandersday.com claims their right-brain dominance gives lefties better spatial awareness, and reversed body dominance gives them a competitive edge.

A 2006 study published in the journal Neuropsychologyby scientists at the Australian National University, the most recent available, which measured the reaction time of left- and right-handed people, found “extreme left-handed” individuals were 43 milliseconds faster at spotting matching letters. They think more quickly. ⁶

Does that definitively prove the theory that lefties are biologically superior on the field and on the stage? Not necessarily. But it doesn’t hurt.

Perhaps it is no coincidence that the list of famous lefties includes Babe Ruth, John McEnroe, Pele (who was also famously left-footed), Lionel Messi, and Martina Navratilova.

Lefties are more creative?

A growing body of evidence suggests lefties are not only creative, but more divergent thinkers, well suited to the modern day work world, which favors “outside the box” brainstorming.

Neuroscientists have shown that left-handers use the right hemisphere of their cerebrum, which is widely viewed as the seat of creativity, more often than right handers.

If pop icons Lady Gaga, Tina Fey, Will Farrell, Eminem, and Paul McCartney are any indicator, lefties do seem to have a flair for the creative.

Add to the left-handed mix artists Leonardo de Vinci, Michelangelo, Vincent van Gogh, Peter Paul Rubens and Henri de Toulouse Lautrec and the anecdotal evidence mounts.

But McManus notes that creativity is tough to measure, and is more often pondered by biased parties than the scientific community.

“The creativity thing is much more pursued by the general public and websites for left-handers than by scientists — creativity is a pretty hard thing to study anyway, which doesn't help,” he said.

Higher rates of psychosis?

Left hand-dominance may well be linked to higher incidences of mental illness, if you believe the results of a study by Yale University in New Haven, Connecticut, and the University of Texas Southwestern Medical Center in Dallas.⁷

In an effort to confirm or dispel more primitive studies throughout the 20 ^th century, which determined patients with schizophrenia are more likely to be left-handed than the general population, the research team assessed 107 patients at outpatient psychiatric clinics.

Their findings? The prevalence of left-handedness was roughly average (11 percent) for mood disorders like depression and bipolar disorder, but it rose substantially to 40 percent for those diagnosed with more serious forms of psychosis, like schizophrenia or schizoaffective disorder.

“The human brain develops asymmetrically, such that certain cognitive processes arise predominantly from the left or right side,” the researchers wrote in their abstract, published in 2013 in SAGE peer-reviewed research journal. “It has been proposed that variations in this laterality contribute to certain forms of mental illness, such as schizophrenia.”

Based on solid meta-analysis, McManus concurs that schizophrenia is “undoubtedly” linked to left-handedness.

They earn more

Some also suggest that left handed men, by virtue of their ability to process information quickly, bring home bigger paychecks.

Perhaps that is true.

A study of “handedness” by the National Bureau of Economic Research reveals the earnings power of highly educated left-handed men was 15 percent greater than that of their right handed peers.⁸

Leftie women showed no increase in their earnings.

Whether or not those data bear out nationally, one thing is true: lefties share the stage with some of history’s most influential business icons — auto industry tycoon Henry Ford, Microsoft President Bill Gates, oil magnate John D. Rockefeller, Facebook founder Mark Zuckerberg, Alan Turing (founder of computer science), and one-time IBM chief executive Lou Gerstner, to name just a few.

If you count yourself among them, you have good reason to celebrate on Aug. 13.

Raise the ink smudge on your left hand high, the proud mark of a lefty who has spent a lifetime dragging his hand across the page; pat yourself on the back for being unique (using your left hand of course) and, above all else, take with a big grain of salt all the myths, speculation, and research you hear.

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This article was originally published in August 2016. It has been updated.

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