Facts about lefties you may not have known

By Skyler Rivera

Published August 13, 2021

Updated 11:07AM

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Aug. 13 is International Left-Handers Day, a day to celebrate all the left-handed people in the world. The annual celebration was created not just to celebrate what makes lefties special, but to highlight the struggles that lefties may face daily in a world designed for right-handers.

How do you celebrate International Left-Handers Day?

On International Left-Handers Day, lefties encourage right-handed folks to try doing things with their left hand. In turn, righties may appreciate the daily struggles and determination of left-handers.

What are the advantages of being left-handed?

According to AA Driving School, left-handers are 10% more likely to pass their driving test. 

Almost six out of 10 (57%) of left-handers pass their test on their first try, according to the study.  

The U.S. National Bureau of Economic Research found that left-handed men with a college degree earn 15% more money than their right-handed counterparts.

Lefties also reportedly have better problem-solving skills.

Four out of the past six U.S. presidents are left-handed. Lefties dominate the Nobel Prize list and makeup 20% of Mensa members.

Are lefties clumsy?

A study of more than 550 children in the Pediatrics journal found that left-handed children were nearly twice as likely to be injured and need medical attention than their right-handed peers.

Harvard University studies suggest that the difference in accident rates may be due to the way lefties cope in a world tailored to right-handers.

What percentage of the world is left-handed?

About 10% of the worldwide population is left-handed.

What causes a person to be left-handed?

Researchers still don’t fully understand why 10% of the population is left-handed, but there are theories.

Genes predispose a child to favor their right hand, but a single gene may be passed from parents to children to influence left-hand favoritism.

Boys are more likely to be left-handed than girls. Some researchers suggest that male testosterone has an influence on hand favoritism.

Some researchers believe that children choose their right or left hand by copying parents and other caregivers. 

Do left-handers have higher IQs?

Bloomberg reports that left-handed people are more likely than right-handed people to have an IQ above 131.

Are lefties better musicians?

While there is an ongoing debate over whether left-handed musicians are better, it’s rather subjective. But The Guardian reports that lefties and ambidextrous people tend to be into more obscure music than right-handers.

Here are some famous lefties:

• Drew Barrymore
• Robert De Niro
• President Barack Obama
• Paul McCartney
• Ringo Starr
• Kurt Cobain
• Justin Bieber
• Brad Pitt
• Babe Ruth
• Julia Roberts
• Oscar De La Hoya
• Tom Cruise
• Angelina Jolie
• President Bill Clinton
• David Bowie
• Jimi Hendrix
• Eminem
• Lady Gaga
• Ricky Martin
• Bill Gates
• Oprah Winfrey
• Steve Jobs
• Mark Zuckerberg
• Henry Ford
• President George H. W. Bush
• Morgan Freeman
• Supreme Court Justice Ruth Bader Ginsburg
• Mark Wahlberg

This story was reported from Los Angeles.

Are left-handed people smarter? | Live Science

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Does this southpaw painter have an cognitive edge?
(Image credit: Westend61 via Getty Images)

Left-handed people comprise only around 10% of the global population, but a quick glance reveals that many key movers and shakers are lefties. 

For instance, three out of the last six American presidents were lefties: George H.W. Bush, Bill Clinton and Barack Obama. Plus, an eclectic slew of outliers who’ve rocked the world in one way or another had dominant left hands: Michelangelo, Leonardo da Vinci, Paul McCartney, David Bowie, Jimi Hendrix, James Baldwin, Nikola Tesla, Oprah Winfrey, Bill Gates and Steve Jobs, according to a 2019 report and The New York Times.  

It’s an impressive roster, but what does the data say? Are left-handed people smarter than righties? 

Related: Why are people left- (or right-) handed?

To investigate this question, researchers looked at the differences in mathematical achievement between more than 2,300 right- and left-handed students between the ages of 6 and 17 in Italy. While there was no difference when looking at the easier math problems, left-handed students had a significant edge on the more difficult problems, such as associating a mathematical function to a set of data, according to the 2017 study in the journal Frontiers, led by Giovanni Sala, an assistant professor at the Institute for Comprehensive Medical Science at Fujita Health University in Japan.

But why would a person’s dominant hand have anything to do with mathematical ability? Left-handedness is associated with some surprising differences in the architecture of the brain. A 1995 meta-analysis of 43 studies in the journal Psychobiology determined that left-handers possess a significantly larger corpus callosum — the bundle of nerve fibers connecting the two hemispheres of the brain — than right-handers do.

“A possibility is that the stronger connection between the two hemispheres allows the [left-handed] subject to have stronger spatial abilities, and we know that spatial abilities are connected to mathematics because mathematics is often conceptualized throughout space,” said Sala, who conducted his research while at the University of Liverpool in the U.K.

In some cases, it might depend on how a person becomes left-handed. “Handedness is a very complex trait, and specifically left-handedness may be an advantage or a disadvantage depending on what the cause is,” Sala told Live Science. Sometimes, “left-handedness can be caused by some kind of brain damage, when the right hemisphere has to take over because there is some kind of damage in the left hemisphere. ” 

This type of damage could be caused by a hemispheric lesion that occurs prenatally, according to a 1985 study in the journal Brain and Cognition. If the lesions occur in the left hemisphere of the brain, then this could lead the individual to predominantly use the right half of their brain. Since the hemispheres of the brain are cross-indexed (meaning the left hemisphere controls the right side of the body, and vice versa), a dominant right hemisphere can lead to left-handedness. The study refers to this as “pathological left-handedness,” and noted that it can lead to learning difficulties. In other words, sometimes being lefty is associated with learning problems.

It’s complex, but Sala’s study paints a picture of left-handers being over-represented at both the bottom and top of the cognitive spectrum. “Once you see that the subject is not intellectually challenged … then left handedness seems to be a predictor of intellectual ability,” specifically mathematical ability, according to his study, Sala said. However, he cautions that his results are not the final word, and that further studies must be done. 

What’s more, other data shows that righties have a slight intellectual edge over lefties. A 2017 study in the journal Neuroscience and Behavioral Reviews reviewed 18 other studies which included data from over 20,400 people and found that right-handers had negligibly higher IQs than left-handers do, on average. “The jury is still out when it comes to the questions of whether it is degree of hand preference that is associated with intelligence and whether there is a relationship between relative handskill and intelligence,” the authors wrote in the study. 

Left-handedness has not always been seen in such a positive light. In the 1936 pamphlet “The Prevention and Correction of Left-Handedness in Children,” by J.W. Conway, left-handedness was described as a “disease” as serious and problematic as rickets and pneumonia. 

Prejudice against left-handers has deep roots and is built into our very language. To be someone’s “right-hand man” is good, while having “two left feet” or receiving a “left-handed compliment” is bad. The word itself comes from the old English “lyft” meaning weak or broken, while the word “right” is given the additional honors of meaning factually correct, morally justified, or a “moral or legal entitlement.” 

RELATED MYSTERIES

These slights are not unique to English, either. The French word for left is “gauche,” which in both English and French also means “awkward or tactless,” while ,”droite,” the French word for right, translates to “adroit.” Going back further still, the Roman word for left was “sinister,” while their word for right, or “dexter,” gives us the English word dexterity.

Even modern research acknowledges some downsides to being of the lefty persuasion. It’s been statistically associated with schizophrenia, dyslexia, and breast cancer, to name a few. (However, an association does not prove that one causes the other. )

But these prejudices just make those numerous left-handers who have become historical and contemporary icons all the more impressive. Not bad for a group of supposed gauche and sinister abnormals, right?

Originally published on Live Science.

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Left-handed people | Clinic Expert

International Left-Handed Day is celebrated on August 13th. Among the dates approved by the world community, this one has settled for a long time – since 1976. Then the “Bill of Rights of Lefties” was adopted. Why was it necessary to create a separate document? And why does the need to remind about the rights of this part of the population persist today?

International Left Handers Day is celebrated on August 13th. Among the dates approved by the world community, this one settled a long time ago – from 1976 years old. Then the “Bill of Rights for Lefties” was adopted. Why was it necessary to create a separate document? And why does the need to remind about the rights of this part of the population persist today?

Who are you?

The percentage of left-handers in the world is small: only 10 – 13 per population. However, absolute right-handers are less than half: from 38 to 42%. The rest are partial right-handed or left-handed. In other words, “with signs of left-handedness” and “right-handedness”. A very rare phenomenon is ambidexters: people who equally own both the right and left hands.

THE PERCENTAGE OF LEFT-HANDERS IN THE WORLD IS SMALL:
10 -13 PER POPULATION. HOWEVER AND
ABSOLUTE RIGHT-HANDED LESS THAN
HALVES: FROM 38 TO 42%

In addition to the dominant hand, there is a dominant leg and a dominant eye. Recent studies have shown that the sense organs also work asymmetrically: the acuteness of smell in the right and left half of the nose is different, and the distribution of taste buds on the tongue is uneven.

There are simple experiments. To reveal the dominant eye, you need to vertically put the pencil and look at the tip with both eyes, then close the right one. Has the image shifted a lot? It means you are right-handed. Left in place? Open your right eye, close your left. If it has shifted now, the left eye is predominant.

The lead foot is the one you take off with when you jump.

Choice before birth

The leading side is laid down genetically. Statistical calculations carried out in 2003 showed that the probability of having a left-handed child in two right-handers is lower than in a right-handed and left-handed marriage. If the left hand is predominant in both parents, the probability increases by 3-4 times. The genes that determine this trait were discovered later: in 2007, the role of LRRTM1 was identified, and six years later, the influence of PCSK6 was studied.

PROBABILITY OF A LEFT-HANDED
CHILD IN TWO RIGHT-HANDED LOWER THAN
IN THE MARRIAGE OF RIGHT-HANDED AND LEFT-HANDED

There was a theory that more right-handers are the result of natural selection in the process of wars. It was put forward by the philosopher T. Carlyle. He assumed that the soldiers who held the weapon in their right hand survived: in this case, the shield remained in the left and covered the heart. However, the hypothesis was not confirmed. Archaeologists have proven that the proportions were formed long before the advent of weapons and tools.

Secrets of the brain

The idea of ​​how the brain of left-handers and right-handers works has also changed. Previously, it was assumed that the hemispheres act as if in a mirror image. Electroencephalography and magnetic resonance imaging of the brain showed that the differences between left-handers and right-handers are deeper. The difference affects the processes of interaction of all departments. During quiet wakefulness, left-handed brains work less synchronously. But in a dream the picture changes.

“We seem to know a lot about the brain. And we don’t just know – we can manage it.” Quote from the material “The head is a dark object, but it is subject to research. What is responsible for what in the brain?

Right-handers have more inhibitory connections between the hemispheres, so the brain operates on the principle of negative feedback. For those who have the leading side on the left, nature has allocated more activators, so the general feedback principle is positive.

Because of these features, left-handers are more likely to suffer from epilepsy. The nature of the attack in right-handed and left-handed people is also different: right-handers, as a rule, feel the approach of a seizure.

On the other hand, compensatory abilities are better developed with left-handedness. Left-handed people recover faster from injuries and strokes because brain structures are more easily rebuilt and take on additional functions.

There is a stereotype in the mass consciousness: left-handers are creative people, while right-handers are rational. However, the facts do not support it. The long list of famous left-handers of the world includes representatives of creative professions and scientists. Writer Franz Kafka, physiologist Ivan Pavlov, actor Charlie Chaplin, physicist Albert Einstein – these people are too different to explain their talent with one feature.

What distinguishes geniuses from the mass of other, “ordinary” people? What is so special about a genius brain, in particular, the brain of Albert Einstein? Read here

Don’t fight nature

Until recently, it was believed that left-handedness is a shortcoming that needs to be corrected. In schools, children were required to write with their right hand only. There were special mittens so that the student, thinking, did not let the left one into the business. And people got used to it. So nothing bad happened?

It turns out that relearning is not harmless at all. Attempts to change the dominant hand restructure the organization of the nervous system as a whole. It does not lead to somatic diseases. However, due to changes in neural connections, many areas of the brain suffer.

Attempts to retrain a child slow down speech development and may cause stuttering. Anxiety also increases, the ability to adapt to a new environment worsens: the resources of the nervous system are spent on the transition to right-handedness.

LEFT-HANDED RE-EDUCATION IS NOT HARMFUL.
ATTEMPTS TO CHANGE THE LEADING HAND REBUILD
ORGANIZATION OF THE NERVOUS SYSTEM IN GENERAL

The feeling of one’s own body in space also changes. Adults, who seem to have successfully learned to wield with their right hand, orient themselves worse on the ground, and are often clumsy.

Modern difficulties

In ancient times, lefties were feared because of prejudices. Otherness was considered a diabolical mark.

In the twentieth century, superstitions came to naught, but this did not alleviate the fate of the left-handers. An exemplary student in the era of collectivism wrote only with his right hand. Retraining was a common practice. But that’s history. Why celebrate International Left Handers Day today?

Life is really easier now. However, it is far from complete prosperity. Left-handers are not retrained in schools, but this idea has not yet left the mass consciousness. Little lefties are under pressure from older relatives and acquaintances. Teachers are forced to explain that left-handedness is a variant of the norm.

Domestic difficulties came to the fore. Familiar objects – from scissors to subway turnstiles – are designed for right-handed actions. Analogues for left-handers are being developed, but access to them is not available everywhere.

A world that is convenient for all is a goal to be achieved.

Text: Daria Ushkova

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Are left-handers really special? – TASS

© Vladimir Smirnov/TASS

August 13 will mark the International Day of Lefties. What science knows about them – in the material TASS

Who are left-handers?

The answer is not as obvious as it seems. Usually, left-handed and right-handed people are judged by the dominant hand. To determine it, questionnaires are used. The most famous is Edinburgh, but they are all similar: a person is asked how he prefers to perform different actions. The most indicative of all is in which hand he holds a hammer, although outside of laboratories and doctor’s offices they are often judged by which hand a person writes with.

There is also a leading leg (and even an eye!). This is noticeable in football: lefties are highly valued because they are more comfortable playing on the left side of the field and it is difficult for right-handed opponents to play with them. In 2016, scientists calculated that 31% of the players in the junior national teams of the Netherlands had the left foot. Outside the field, left-handers are three times less common: they are slightly more than 10%, and another 9% of people prefer one or the other hand (and, for that matter, a leg).

But regardless of preference, people can still use their second hand. How well this is done is evaluated by three indicators: grip strength, speed and agility. It would seem that skill is directly dependent on preferences, but experiments show that this is not always the case. Someone’s second hand obeys better than others, in addition, a specific task matters.

Perhaps it is more correct not to divide people into two clear groups, but to place them on a scale where there are pronounced left-handers and right-handers at the edges, but there are also intermediate cases. And geneticist and neurologist Daniel Geschwind once said that left-handed people are more accurately called “wrong-handed” because they often use both hands well.

Why are some left-handed and others right-handed?

Already at the 14th week of pregnancy, the human embryo usually turns its head to the right and sucks the finger of the right hand (it is interesting that only two-thirds of people tilt their heads to the right when kissing – another example for the scale and against dividing into two groups). This usually indicates whether the child will be right-handed or left-handed, a trait that can be assumed to be somewhat innate.

One hypothesis is that lefties in the womb develop their brains in a special way because of testosterone. Therefore, there are about a quarter more left-handers among men than among women. And the level and susceptibility to testosterone may depend on the genes of the mother and child. Heredity is also indicated by the fact that left-handed parents are more likely to have the same children, and if one of the twins is left-handed, then the second will be more likely than the average. True, it happens differently.

Scientists tried to find the gene that determines this trait. There were several candidates under suspicion. When DNA deciphering became cheaper, dozens of small differences were discovered, which individually slightly affect whether a person is left-handed or right-handed. But, firstly, it is not clear exactly how they act, and secondly, even all together they do not allow you to say with certainty who is standing in front of you.

An analysis of data on half a million Brits has shown that there are more left-handers among those born with underweight, twins and women born in the summer, but if you take all seasons, then there are still more left-handed men. They are more likely to be those who are not breastfed. Finally, the proportion of left-handers increased until 1970, and among those born outside the UK, there are almost a third less of them. The last two patterns are easier to explain by prejudice and upbringing than by nature.

What are the prejudices about lefties?

In many cultures, the left side is bad. For Christians, the left hand is associated with the devil, for Muslims it is considered unclean. When someone is out of sorts, we ask, “Did you get up on your left foot?” The words “right” and “correct” are similar for a reason. And the English word sinister, which means “sinister”, “bad”, came from the Latin for the left hand. In English, left-handedness is still called sinistrality. That is why left-handed people have been treated with caution from time immemorial.

In the USSR and other countries they were retrained, and sometimes they still do it. It’s not so much about superstition or the fact that left-handedness is considered a pathology – it’s just that many things, such as computer mice, are made asymmetrical, convenient for right-handed people. But in the second half of the 20th century, when this practice was gradually becoming a thing of the past, there were suggestions that left-handedness – at least in some cases – is still a deviation in the development of the brain.

So is left-handedness a pathology or a variant of the norm?

Although left-handedness is a well-known but mysterious phenomenon, it was not really studied until the 1970s. After that, scientists hypothesized that left-handers become due to birth injuries or that during pregnancy, sex hormones (primarily the mentioned testosterone) can disrupt brain development. These guesses were backed up by statistics: supposedly, left-handed people are more likely to have some neurological, mental disorders, and even autoimmune diseases, and they live an average of seven years less than right-handed people.

On this topic

But left-handers and right-handers are not only among people: they are pigeons, bees, zebrafish and other animals that are separated by millions of years of evolution. True, such a large disproportion, as in humans – nine right-handers to one left-hander – is rare. For example, in higher primates, according to some estimates, this ratio is 65/35.

These differences come down to the functioning of the nervous system, primarily the brain. The hemispheres of the brain are responsible for different functions. Why this is so is not entirely clear. The main hypothesis is that duplicating functions would be inefficient. The brain accounts for only 2% of body weight, but it consumes 20% of energy, and a large head in children complicates childbirth. Specialization also allows faster processing of information and even parallel computing.

It was once thought that right-handed people were left-brain dominant, while left-handed people were right-brain dominant. In fact, not much is known about this. A recent experiment showed that in right-handed people, one hemisphere is more likely to suppress the other, and in left-handed people, they are more likely to work in concert. True, the participants performed only one simple task (pressing a button), and the difference in brain function manifested itself only in the fact that left-handers, on average, did better with their right hand than right-handers with their left. In other experiments, verbal abilities and orientation in space were tested: according to the first indicator, left-handers and right-handers do not surpass each other, but orient themselves slightly better than right-handers.

Left-handers are probably different from right-handers, but good research is lacking and the difference doesn’t seem to be as big as stereotypes suggest. Not all right-handers listen only to the mind, just as not all left-handers have exceptional intuition and creative abilities. Lefties are indeed more likely to have dyslexia, schizophrenia, and other disorders, but this does not mean that left-handedness is a pathology.