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Happy Left-Handers Day: Experts Explain 7 Things You Probably Didn't Know About Handedness

By dsorbello at Aug. 13, 2015, 8:50 a.m., 23807 hits

By Marc Torrence

August 13 is Left Handers day, celebrating the 11 percent of the world that uses their left hand for tasks like writing, eating and holding things.

Some things we can say for sure about handedness: 13 percent of men are left-handed, while it’s just 10 in women; handedness generally falls on a scale instead of hard and fast left or right; and six of the past 12 presidents have been lefties.

Patch spoke with two respected researchers in psychology and handedness. Here are seven things they explained to help you know your left-handedness from your right.

1. Nobody is exactly sure if handedness is totally genetic or not

Dr. Clare Porac, a professor of Psychology at Penn State who is writing a book called Laterality: Exploring the Enigma of Left-Handedness, said, “There’s consensus that there’s a genetic component,” but it’s not always predictive.

In identical twins, if one is left-handed, the other is left-handed only 75 percent of the time, according to Daniel Casasanto, an assistant professor in the Department of Psychology at the University of Chicago who has done extensive research on handedness.

Environmental factors play a major role too.

Porac said that a child is more likely take after their mother’s handedness. Many theorize that this happens because children traditionally see their mother more during childhood and take after their actions.

2. No, lefties aren’t necessarily smarter or cooler than righties

There is a popular notion that since motor activity is controlled by the opposite side of the brain, left-handers are right-brained, where things like music and visual art are processed.

Sorry lefties, that isn’t the case.

“They really don’t have many cognitive differences from right-handers,” Porac said. “Having your handedness controlled by the right brain does not give you special abilities.”

So, that whole president thing, she says, “is probably just a coincidence.”

And Casanato, whose first paper was published debunking this myth, takes that theory a step further, saying that even the ideas of being “left-brained” and “right-brained” are blown out of proportion.

“The idea that lefties are right-brained and righties are left-brained doesn’t make any sense,” Casasanto said. “Because the idea of being left-brained or right-brained is blowing a few facts way out of proportion.”

3. Humans have had dominant hands for a long time

There’s actually a history of humans favoring one hand or the other.

“If you look at the anthropological record, back to the early hominids, there’s always been a percentage of left-handers,” Porac said.

According to Porac, some scientists believe that handedness evolved when humans split from chimpanzees and started using sounds for communication. Because the brain was using its speech-controlling left side more, motor skills on the right side became more developed.

But there was a survival advantage for lefties.

When early humans engaged in hand-to-hand combat, the left-handers were at an advantage since righties aren’t used to fighting their dominant hand counterparts, a phenomenon we still see today in fencing and boxing.

4. It’s not too hard to switch hands with some tasks

If you wanted to switch handedness, you could, in theory, make it work. At least with small tasks.

“I would imagine that the more skilled and stereotyped activities like writing are going to be really hard,” Casasanto said, while things like brushing your teeth or eating wouldn’t be too hard.

Handwriting For Heroes deals with this firsthand. They work with amputees who lost their dominant hand to teach them how to write, with pretty good results. It’s an intensive course that promises to get you writing with your non-dominant hand within six weeks.

Casasanto was conducting one experiment, and a subject who identified as a lefty was showing a lot of traits common in righties.

It turns out the subject was a basketball player who’d had his left arm in a cast for months and had adapted much of his life to his right hand in a short amount of time.

“It appears some of these things can be switched rapidly,” he said.

5. There are subconscious effects

An even handedness distribution across party lines in recent presidents made for a ripe field of some research in this area.

Casasanto studied spontaneous hand-gestures during the 2004 and 2008 presidential debates. Barack Obama and John McCain were both lefties. John Kerry and George Bush were righties.

The candidates tended to gesture with their dominant hand for positive statements and non-dominant hands for negative statements.

“If you ever see Obama gesturing with his right hand,” Casasanto said. “That’s an indication, perhaps, of how he really feels about something.” Translation: not good.

6. Handedness can influence your decision-making

Casasanto ran an experiment where he showed subjects random drawings of alien creatures and asked them which appeared smarter, happier or more friendly.

On average, subjects chose the creature on the side of their dominant hand.

“People tend to feel positively about things that they encounter on their dominant side of space,” he explained.

This phenomenon—righties like things on the right, lefties on the left—has wide-ranging implications that have been tested in similar studies.

People gravitate toward product descriptions on their dominant side of a page. Hiring managers were more likely to pick the resume on their dominant side.

Even in elections, candidates on the right side of the ballot get a small bump from righties because of this bias, and vice versa.

“The hands shape the mind,” Casasanto said.

Rolf Reber, a psychology professor at the University of Oslo, aptly described it in a paper title: “Beauty is in the Processing Experience of the Beholder.”

7. …but it can be manipulated

In another experiment, Casasanto brought subjects into a lab and had right-handers randomly handicapped with a bulky ski glove on one hand, with the empty glove clipped to it to make things even harder.

They were assigned to carefully arrange dominoes on a table according to certain patterns.

Immediately afterwards, he gave them the alien test again. The ones that were still using their free right hands showed that same right-side preference.

The others, though, showed bias as strong people who had been left-handed their entire lives.

“You can at least temporarily change this bias in the order of 12 minutes of restricted activity,” he concluded.

So, for true Democracy, we should all just wear gloves when we vote.

— Last Edited by Greentea at 2015-08-13 18:25:34 —

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