Left-Handedness and Your Health
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There’s no denying it. Left-handers are the odd ones out.
Sure, lefties make up about 10 percent of the population -- but, frankly, it seems like society has forgotten about them. Just consider all of the right-handed gadgets, awkwardly designed desks, and cooking tools that fit comfortably only in your right hand.
What causes someone to become a southpaw? Scientists aren’t exactly sure, but research points to a complex collaboration between genes and environment. While no exact set of “leftie genes” have been discovered, people who dominantly use their left hands do have more left-handed family members. And researchers have found different brain wirings in righties vs. lefties.
But no matter what it is that drives someone to use their antipodal paw, science has also uncovered a particular set of personality traits that left-handed people tend to have. So for all of you lefties, leftie-loving righties, and ambidextrous folks out there -- it’s time to brush up on your left-handed knowledge and help put an end to leftie discrimination once and for all.
Lefties Have a Higher Risk of Psychosis
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Lefties make up about 10 percent of the general population. But researchers have found that in populations with certain mental disorders, that rate goes up. Previous studies have found that people with psychosis had a 20 percent likelihood of being left-handed, though a small study in the journal SAGE found the rate of psychotic lefties may be even higher.
Researchers at Yale University in New Haven, Connecticut, and the University of Texas Southwestern Medical Center in Dallas assessed 107 patients at outpatient psychiatric clinics. For those with mood disorders such as depression or bipolar disorder, the rate of left-handedness was close to average, at 11 percent. But in people with psychosis, such as those with schizophrenia or schizoaffective disorder, the rate of left-handedness was 40 percent, well above average. Researchers theorize brain laterality plays a role.
Your Handedness May Determine Your Health
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Scientists have also found an increased risk for dyslexia, ADHD, and certain mood disorders in left-handed people, according to a 2010 study published in Pediatrics. Researchers are not exactly sure how to explain this phenomenon, but many believe it's related to how the brain is wired. Your noggin is divided into two halves: the left side and the right side. Most people (righties and lefties alike) rely on the brain's left hemisphere for tasks like language functioning. But about 30 percent of left-handed folks are either partial to the right hemisphere or have no dominant hemisphere at all. According to scientists, having one hemisphere dominate is much more efficient, which is why some left-handers are at increased risk for learning impairments and brain disorders.
But lefties may be in luck when it comes to other health conditions: Results of a large survey published in the journal Laterality found that left-handers had lower rates of arthritis and ulcers.
Lefties Hear Speeches Differently
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People who use their left hands when listening may more easily hear slowly-changing sounds than those who use their right hands, according to a study from Georgetown University Medical Center
The researchers who conducted the study, presented at Neuroscience 2012, found that the left and right hemispheres of the brain specialize in different kinds of sounds. The left hemisphere, which controls the right hand, likes rapidly-changing sounds like consonants, while the right hemisphere, which controls the left hand, likes slowly-changing sounds like syllables or intonation.
According to the researchers, if you're waving an American flag while listening to a presidential candidate, the speech will sound slightly different to you depending on whether you're holding the flag in your left or right hand. The research could ultimately result in better treatment for stroke and language disorders.
Left-Handed Neanderthals Were the Minority, Too
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Right-handed bias isn’t just a modern-day phenomenon: It turns out we’ve been dominantly using our right hooks for more than 500,000 years.
University of Kansas researchers recently determined the handedness of ancient humans by studying -- oddly enough -- their teeth. The study, which was published in the journal Laterality, found that when our great-great-great-great-(you get the point)-grandfathers processed animal hides, they would hold one side of the carcass in one hand and the other in their mouth. By locating the wear and tear on those prehistoric chompers, scientists were able to determine whether our prehistoric ancestors were using their left hand or right hand more dominantly
"All you need to have is a single tooth, and you can tell if our assumptions are right -- if the individual is right- or left-handed," study researcher David Frayer, Ph.D., told LiveScience. The results? "The fossils are just like humans in that we are mostly right-handed, and so were they."
Lefties Make Better Artists
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Southpaws have been bragging about their creative clout for years. But is it true -- does being left-handed mean you’re also more likely to be artistic or innovative?
According to research published in the American Journal of Psychology, there is some evidence that left-handed people have the upper hand in at least one creative facet: They’re better at divergent thinking, a method of idea generation that explores many possible solutions.
To determine whether lefties were more likely to pursue creative careers than righties, the folks behind the Left-Handers Club (a pro-leftie group dedicated to left-handed research and product development) surveyed more than 2,000 left-handed, right-handed, and ambidextrous participants and found that lefties tended to find advantages and be drawn to careers in the arts, music, sports, and information-technology fields.
But that may also add up to lower paychecks: According to a report in the Wall Street Journal, left-handers’ salaries are 10 percent lower on average than those of right-handers.
We Vote for Left-Handers!
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It doesn’t matter which way they swing politically: A surprisingly high percentage of recent U.S. presidents were on the left (in terms of handedness, of course).
The lengthy list of left-handed leaders includes four of the last seven commanders in chief -- President Obama, Bill Clinton, George H.W. Bush, and Gerald Ford -- as well as past presidents James Garfield and Harry Truman. In fact, there’s a rumor that Ronald Reagan was born a leftie, but stringent schoolteachers converted him to a righty when he was young.
Should right-handed presidential wannabes fake it? Our penchant for left-handed POTUSes is probably pure coincidence. But one recent Dutch study suggests that left-handed politicians actually have an advantage in televised debates. As a whole, people tend to associate right-handed gestures with “good” and left-handed gestures with “bad,” according to the researchers. Since television presents a mirror image, the lefties are the ones who appear to gesture with their right hands (the “good” hand).
Southpaws Will Beat You in Sports
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Golf legend Phil Mickelson, tennis ace Rafael Nadal, boxing champ Oscar de la Hoya -- did you know that a number of your favorite sports superstars are lefties?
Actually, left-handers may have the advantage in sports that involve two opponents facing each other, such as in tennis, boxing, and baseball, according to an MSNBC review of the book The Puzzle of Left-Handedness, by Rik Smits. The author chalks it up to the fact that left-handed athletes get a lot more opportunity to practice against right-handed opponents than vice versa (since there are so many more righties out there).
Now that’s a home run for lefties.
Lefties Are Scaredy-Cats
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If you’re a left-hander, that probably made you cringe. That’s because people whose left hands are dominant tend to be more affected by fear than people who use their right hands, according to research presented at an annual conference of The British Psychological Society and reported in the Telegraph.
For the study, participants watched an eight-minute clip from the frightening film Silence of the Lambs. When asked to recall events from the segment, lefties were far more likely to show signs of post-traumatic stress disorder than righties, including giving fragmented descriptions and making more mistakes.
"It seems that after experiencing a fearful event, even on film, people who are left-handed had subtle behaviors that were like people suffering from post-traumatic stress disorder," head researcher Carolyn Choudhary, PhD, told the Telegraph. Blame the brain: “It is apparent that the two sides of the brain have different roles in PTSD, and the right hand-side of the brain seems to be involved in fear. But we need to do more experiments to understand what exactly is going on here,” she said.
Grrr! Left-Handers Get Angrier, Too
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If you just can’t let go of that spat you had with your right-handed pal (but he seemed to move on just fine), you may be able to blame it on your left-handedness. According to a small study published in the Journal of Nervous and Mental Disease, lefties are more prone to having negative emotions. In addition, they seem to have a more difficult time processing their feelings.
Again, this seems to be related to the brain-hand connection. Compared to righties, left-handed participants in the study showed an imbalance in activity between the left and right hemispheres when trying to process their moodiness.
Easily Embarrassed? Could Be Because You're a Leftie
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Aw-shucks. Lefties may get bent out of shape, but research shows they're just a bunch of bashful self-observers.
When scientists from Abertay University in Scotland gave 46 lefties and 66 righties behavioral tests to measure their impulsiveness and personal restraint, the left-handers in the group more commonly agreed with statements like "I worry about making mistakes" and "Criticism or scolding hurts me quite a bit." In fact, their answers left researchers believing that lefties tend to feel more inhibited, shy, and embarrassed than their right-handed counterparts.
"Left-handers are more likely to hesitate, whereas right-handers tend to jump in a bit more," lead researcher Lynn Wright, PhD, told BBC News.
Lefties Like to Booze
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Next time you have a run-in with a boozed-up barfly, check out which hand he’s holding his whisky with: chances are, it’ll be his left.
For years, myth has held that left-handers are more likely to become alcoholics. Research into the topic was murky, however, and relied on small samples. But a survey of more than 25,000 people from 12 countries has cleared things up a bit. While lefties are not more prone to alcoholism, they do drink more often.
Researcher Kevin Denny, who examined the data for a paper published in the British Journal of Health Psychology, says the main takeaway should be debunking that whole left-handedness-alcoholism link. “There is no evidence that handedness predicts risky drinking,” he stated in a press release. “Hence, the results do not support the idea that excess drinking may be a consequence either of atypical lateralisation of the brain, or due to the social stresses that arise from left-handers' being a minority group.”
They Have Their Own Day!
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Mark your calendar: August 13 is International Left-Handers Day.
Lefties across the globe celebrate the annual event, which was launched in 1992 by the UK-based Left-Handers Club to increase awareness about the left-handed lifestyle. According to the group’s Web site, it’s a day “when left-handers everywhere can celebrate their sinistrality and increase public awareness of the advantages and disadvantages of being left-handed.”
How should you observe the occasion? Create a “leftie zone”: a designated area of personal space where everything must be done in a left-handed fashion, from your workspace setup to the way you use cutlery.
And that rule also extends to any right-handers who happen to enter the leftie zone.
Lefties Aren't Going Anywhere
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Left-handers are the minority. So does that mean they’ll go extinct one day? In fact, some researchers believe that when it comes to survival of the fittest, lefties come out on top.
Here’s why: In one-on-one combat, using the left-hand is like throwing a curveball. "The fact that left-handers are less common means they have a surprise effect," University of Montpellier researcher Charlotte Faurie told ABC News. To dig deeper, Faurie and her colleague Michel Raymond studied nine different primitive societies. In more violent societies, they found, lefties thrived (think southpaw slugger Rocky Balboa’s left hook).
Looks like the left hand has the upper hand after all.
Correction: An earlier version of this post stated that people who use their left hands hear rapidly-changing sounds more easily than those who use their right hands. In fact, left-handers hear slowly-changing sounds better.
12 Little-Known Facts About Left-Handers originally appeared on Everyday Health.
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