Left handed people percentage

Today is a day to celebrate the lefty (Picture: Getty)

Today, 13 August, is Left Handers Day, which is apparently an opportunity ‘to tell your family and friends how proud you are of being left-handed, and also raise awareness of the everyday issues that lefties face’.

That is according to the Left Handers Club, who started the special day in 1992 and point out that we ‘live in a world designed for right-handers.’

Man shot dead by police as two stabbed in London terror attack

This is true, because the vast majority of human beings are right handed, making the left handed products much more difficult to come by.

So how many people are left handed and why is it that the trait is so unusual?

(Picture: Getty)

How many people are left handed?

The estimated percentage of left handed people across the globe is 8-15%, with most figures studies suggesting it is 10-12%.

Advertisement Advertisement

Taking the average of 11%, this would mean that 836,000,000 people are left handed across the globe, out of a population of 7.6 billion.

It has also been shown in a 2008 study that a left handed person is 23% more likely to be male than female.

(Picture: Getty)

Why are so many more people right handed than left handed?

There is no definitive answer to this question, but the most accepted theory relates to which side of the brain controls the right hand.

According to Jason Goldman for the BBC, the right side of the body is largely controlled by the left hemisphere on the brain, the same side of the brain that deals with language.

It was about 1.5 million years ago that evidence of right handed dominance became clear through tools found in Kenya, whereas there was little or no evidence that there was a preference before that.

It is from that time on that language is believed to have developed in humans and with the left hemisphere processing the linguistic skills, right handedness may well have occurred as a side effect.

This is called the Homo loquens hypothesis.

(Picture: Getty)

So why are some people left handed?

It appears that some people’s brains are organised differently to the majority, although this is not necessarily a negative thing.

‘Left-handers are much more variable in the way that their brains are organised,’ explained psychologist Chris McManus, from University College London, to the BBC.

A certain amount of mystery surrounds left handedness (Picture: Getty Images/PhotoAlto)

‘My personal hunch is that left-handers are both more talented, and suffer deficits. If you are left-handed you might find yourself with a slightly unusual way your brain is organised and suddenly that gives you skills that other people don’t have.’

Advertisement Advertisement

Dorothy Bishop is Professor of Developmental Neuropsychology at the University of Oxford, looks at it differently: ‘I myself am left-handed and I always wondered why I was different from other people.

‘There’s been all sorts of claims over the years linking left-handedness with disabilities like dyslexia and autism. On the other hand, there have been positive attributes – it’s claimed that architects and musicians are more likely to be left-handed.’

MORE: Why is your penis shaped like a mushroom?

MORE: Masked men attack BMW with baseball bats as boy, 5, cowers in the back

Advertisement Advertisement

Your Left-Handed Brain

Abstract

While most people prefer to use their right hand to brush their teeth, throw a ball, or hold a tennis racket, left-handers prefer to use their left hand. This is the case for around 10% of all people. There was a time (not so long ago) when left-handers were stigmatized (see Glossary) in Western (and other) communities: it was considered a bad sign if you were left-handed, and left-handed children were often forced to write with their right hand. This is nonsensical: there is nothing wrong with being left-handed, and trying to write with the non-preferred hand is frustrating for almost everybody. As a matter of fact, science can learn from left-handers, and in this paper, we discuss how this may be the case. We review why some people are left-handed and others are not, how left-handers’ brains differ from right-handers’, and why scientists study left-handedness in the first place.

Why are You Left-Handed?

Despite many years of research, the reason why one person turns out to be a left-hander and another does not remains a mystery. Handedness is partly heritable (see Glossary): left-handed parents tend to have more left-handed children than right-handed parents do. Studies that compared identical twins to fraternal twins (see Glossary) show that the heritability is around 25% , which suggests a genetic contribution to hand preference. Note, however, that if handedness is only 25% heritable, then the majority of the factors contributing to left-handedness is not straightforwardly genetic. A much debated influence is the level of the hormone testosterone in utero (in the womb) while an unborn child (fetus) is developing. Another possibility is that handedness is influenced by random (“chance”) processes that occur during the early development of an unborn child, when it is still very small. Regarding the heritable factors, researchers have found several genes which may be involved in handedness. Interestingly, it seems that there is not one gene which contributes to determining whether people are left-handed or not. Most likely, different genetic influences are involved.

Of course, children learn from their caregivers, so one may expect that if one of the parents is left-handed, the child might become left-handed just by imitation. One reason why this cannot be the full story is that hand preference can already be observed before birth. Fetuses like to move around, and one can predict a child’s hand preference reasonably well by looking at which arm and hand they prefer to move before birth, as can be seen with ultrasound scanning . This observation of fetal handedness is at odds with the finding that some children seem to switch their hand preference, at least up to the age of 2 . Perhaps some people are left- or right-handed at birth, whereas others develop their preference later on, during the first years of life.

Are you confused about what makes a person left-handed or not? So are we! Whatever the exact causes may be, this is not a simple story, but a very complex interplay of genes, environment, and chance. Let us leave this topic for now, and have a look at the left-handed brain.

Is the Left-Handed Brain Different?

Sometimes, people are amazed to hear that the brains of left-handers are different from those of right-handers. But it is clear that they should differ in some respects: left-handers use their hands (and feet) differently than right-handers do, and they do this often over the course of a lifetime. It is only natural that the parts of the brain that control movements should be different in left-handers and right-handers (Figure 1). Compare this to skilled musicians: they practice fine movements a lot, and this influences their brains1. To study exactly how the brains of left- and right-handers differ, we need to look at brain lateralization.

  • Figure 1 – Brain activation when participants imagined performing common hand actions.
  • Left- and right-handed participants imagined performing actions such as throwing or writing. It is striking that in left-handers (yellow), only areas of the right side of the brain were activated, whereas it was the opposite in right-handers (blue). Left-handers thus imagine themselves writing with their left hand, which is mainly controlled by the right hemisphere, and vice versa for right-handers. Picture from Willems et al .

Brain lateralization refers to the fact that the left and right sides of the brain are not the same. The two sides differ in their anatomy, and also in what they do. By the way, lateralization is also found in the rest of the body: the two arms look slightly different, and are capable of doing different things; the heart is lateralized to one side of the body cavity, etc. Left-handers are distinct from right-handers in that they tend to have less lateralization in the brain. A well-known example of this is language, which is mainly a function of the left side of the brain in right-handers2. Although left-sided language areas in the brain are still important in left-handers, the difference between left and right sides tends to be less strong. A similar example comes from face perception, which is rightward-lateralized in the majority of people, meaning that mainly right-sided parts of the brain are responsive to faces. Again, left-handers tend to use both left and right regions of the brain relatively often when they see a face .

Do Left-Handers Think Differently?

Does this mean that left-handers think differently? Well, yes and no. There have been lots of suggestions of left-handers’ increased creativity, but there is very little firm evidence on this. Increased musical abilities are another often-cited skill that left-handers might possess, but again, there is very little evidence to support this. Many claims about left-handers’ superior skills are based on lists of famous musicians that circulate on the internet. While amusing, these lists span several decades of pop music, and you will find (if you try) that for every left-handed guitarist in such lists, you could easily come up with enough right-handed guitarists to match the usual 9:1 ratio of right- and left-handers in the population. Although there is no good evidence for left-handers being more gifted than right-handers, the opposite is also true: there is no clear evidence that left-handers perform more poorly on tests of cognition. This had been suggested for a long time (see our comment above on stigma).

Left-handers may think differently in another respect, though. A potent idea is that we understand action words like “writing” by using the parts of our brains that control our own movements, as though we were writing ourselves when we see or hear the word “writing.” This idea is sometimes called “embodied cognition.” It was tested by looking at activity of the left and right motor cortex (a brain region involved in movement) in left- and right-handed people while they listened to words such as “writing” . Left-handers activated the motor cortex that controls their left hand, whereas right-handers activated the motor cortex that controls their right hand – as if they were really writing, while they were only listening to the word.

On a related note, left- and right-handers differ in how they judge positive and negative attributes of things in the space around them. In one experiment, participants had to judge “Fribbles” (nonsense figures; see Figure 2) in terms of honesty and intelligence. The figures were presented on either the left or right side of a screen. Left-handers rated figures presented on the left in more positive terms, and right-handers rated figures on the right in more positive terms .

  • Figure 2 – Participants were asked to circle which of two “Fribbles” they thought was most intelligent, happy, etc.
  • Left-handers rated Fribbles presented on the left side of the page as more positive, whereas right-handers did the opposite. The explanation for this finding was that left-handers act most fluently with the left side of their body, and right-handers with the right side of their body. Because of this fluency difference, positive and negative attitudes are also mapped onto opposing sides of space .

It seems that the way in which we do things with our hands influences our thinking, at least to some extent.

Why Do We Study Left-Handedness?

Left-handedness is an intriguing phenomenon in its own right. However, scientists do not study left-handedness just because it is a fun topic. Left-handedness can shed light on diverse issues that go beyond the study of hand preference per se. Here are two more examples, in addition to the research we already described:

  • Human uniqueness. Other primates (e.g., the great apes) do not show such a strong population bias toward using the right hand as humans do. Over the course of evolution, there must have been changes in the brain that resulted in most humans preferring to use their right hands, while at the same time maintaining a stable minority that prefers to do things with the left hand. Why was this case, and what could have been the advantages? The lateralization of language in the brain (see above) has led to speculation that early humans started to communicate with their hands first, and only developed spoken language later.
  • Genes that create left-right asymmetries in the brain. Identifying genes that influence hand preference may shed light on the basis of lateralization of the brain and other body functions. How this arises during development is still poorly understood, but it is a very important aspect of our biology.

Summary

Left-handers are a sizeable minority of people (at least 10%). Hand preference is partly heritable, pointing to a genetic contribution. However, the relevant genes are likely to interact with environmental and chance factors to determine the handedness of a specific person. The brains of left-handers and right-handers are somewhat different. Left-handers tend to have less lateralized brains, meaning that the two halves of the brain are less distinct than in right-handers. The study of left-handers can help us answer several important scientific questions. All of this means that left-handers have many reasons to feel special, for after all, the large majority of people are not left-handed. At the same time, bold claims about creativity and other ways in which left-handers may be super-gifted are probably not true.

Footnotes

Also, individuals who are born with exceptional properties for the parts of their brains involved in movement and music perception may be predisposed to become skilled musicians.

This does not mean that the right side of the brain does nothing during language comprehension. Quite the contrary, it is also active, but less so than the left side.

Glossary

Stigmatization: To disapprove of people with a certain characteristic or behavior.

Identical twins and Fraternal twins: Identical twins develop from the same fertilization and therefore share virtually all of their DNA. They differ from fraternal twins, who develop from different fertilizations and are only genetically related, like any other pair of siblings.

Heritable: A characteristic that can be inherited, because genes affect the way it develops.

Further Reading

McManus, I. C. 2002. Right Hand, Left Hand. London: Phoenix.

Smits, R. 2011. The Puzzle of Left-Handedness. London: Reaktion Books.

Acknowledgements

We are thankful to Hélène Cochet and Jacqueline Fagard for their helpful suggestions on the developmental section.

Cochet, H. 2012. Development of hand preference for object-directed actions and pointing gestures: a longitudinal study between 15 and 25 months of age. Dev. Psychobiol. 54:105–11. doi: 10.1002/dev.20576

M.K. Holder is an affiliated scientist in the Center for the Integrative Study of Animal Behavior at Indiana University. She replies:

In the 160 years in which “handedness” has been studied we have learned quite a lot, but we still cannot precisely describe what causes humans preferentially to use one hand over the other, or why human populations are biased toward right-hand use rather than left-hand use.

Scientists disagree over what percentage of human populations are “right-handed” or “left-handed” because there is no standard, empirical definition for measuring “handedness”; our criteria vary, and are based on various theoretical explanations because we are still trying to understand the mechanisms involved. But I can describe in general terms what we do know.

Most humans (say 70 percent to 95 percent) are right-handed, a minority (say 5 percent to 30 percent) are left-handed, and an indeterminate number of people are probably best described as ambidextrous. This appears to be universally true for all human populations anywhere in the world. There is evidence for genetic influence for handedness; however, it is non-Mendelian and geneticists cannot agree on the exact process. There is evidence that handedness can be influenced (and changed) by social and cultural mechanisms. For instance, teachers have been known to force children to switch from using their left hand to using their right hand for writing. Also, some more restrictive societies show less left-handedness in their populations than other more permissive societies.

Some researchers argue there is evidence for cases of “pathological” left-handedness related to brain trauma during birth. And many researchers trace the cause of handedness back to pre-natal, interuterine developmental processes, back to the time when the fetal brain is first developing distinct cerebral hemispheres. In the 1860s the French surgeon Paul Broca noted a relationship between right-handedness and left-hemispheric brain specialization for language abilities. But the hand-brain association is neither a simple, nor reliable, correlation. Studies conducted in the 1970s showed that most left-handers have the same left-hemispheric brain specialization for language typical of all humans–only a portion of left-handers have different patterns of language specialization.

So the bottom line is, we have a good general idea of the causes of right-handedness in human populations, but we have yet to work out the precise details, including why the direction is right instead of left.

Do other primates show a similar tendency to favor one hand over the other?

The second question (do non-human primates show handedness) is currently a controversial one. It is important to note the difference between an individual animal being left- or right-handed, and most of the animals in an entire population being either left- or right-handed. It is not unusual for individual animals to show a preferential use of one hand over the other, to develop an individual hand preference. But there is no consensus among researchers that any non-human species shows the same species-level handedness found in humans.

There are a few researchers who argue for this, but most of these work with animals in laboratory or captive settings, performing manual tasks that are very different from how animals use their hands in the wild.

In addition to studying handedness in humans, I have also studied hand usage in mountain gorillas (in Rwanda) as well as chimpanzees, red colobus monkeys, redtail monkeys and grey-cheeked mangabeys (in Uganda). My own research shows that individual monkeys and apes often develop individual preferences (both left and right) for manual tasks, but I have found no evidence for population-level handedness, as seen in humans.

Answer originally posted August 18, 1997.

source Iryna Inshyna /

  • Tuesday August 13 is International Lefthanders Day.
  • About 10% of the population is left-handed.
  • There have been several theories over the years about why some people favor their left hand.
  • A study published last year found that right- or left-handedness may have nothing to do with the brain – instead, it could be determined by gene activity in the spinal cord while you are in the womb.
  • Visit Business Insider’s homepage for more stories.

Left-handed people haven’t always been treated well throughout history. They’ve been persecuted for their disposition, being been labeled as evil – or even as witches – despite making up about 10% of the population. In fact, the word “sinister” comes from “left” or “left hand.”

There have been a few theories over the decades about why some people are left-handed, including an outdated idea that it has something to do with mothers who are stressed while pregnant.

It’s down to the spinal cord – not the brain

Research since the 1980s has found that our preference for our left or right hand is most likely determined before we are born – ultrasound screenings suggest as early as the eighth week of pregnancy. From the 13th week in the womb, babies tend to suck either their right or their left thumb.

It was previously thought that the genetic differences between the left and right hemispheres of the brain determine whether someone is left- or right-handed. But a study published last year in the journal eLife found that the answer could lie in the spinal cord.

The research – by Sebastian Ocklenburg, Judith Schmitz, and Onur Gunturkun from Ruhr University Bochum, along with other colleagues from the Netherlands and South Africa – found that gene activity in the spinal cord was asymmetrical in the womb and could be what causes a person to be left- or right-handed.

Arm and hand movements start in the brain, in an area called the motor cortex, which sends a signal to the spinal cord that’s translated into a motion. The researchers found that while the fetus is growing in the womb, up until about 15 weeks, the motor cortex and the spinal cord are not yet connected, but right- or left-handedness has already been determined.

source PATRICK BP/

In other words, the fetus can already start movements and chooses a favorite hand before the brain starts controlling the body.

To study this, the researchers analyzed gene expression in the spinal cord in the eighth through the 12th week of pregnancy. They found significant differences in the left and right segments of the spinal cord that control arm and leg movement.

They concluded that the asymmetrical nature of the spinal cord could be down to something called epigenetics, or how organisms are affected by changes in their gene expression rather than in the genes themselves. These changes are often brought about by environmental influences and can affect how a baby grows.

These gene-expression differences could affect the right and left parts of the spinal cord differently, resulting in lefties and righties.

So why are lefties so rare?

Scientists have long tried to answer this.

In 2012, researchers at Northwestern University developed a mathematical model to show that the percentage of left-handed people was a result of human evolution – specifically, a balance of cooperation and competition.

In other words, they thought that, though the basis for right- or left-handedness may be genetic, there could be a social factor that explains why the ratio is so high.

“The more social the animal – where cooperation is highly valued – the more the general population will trend toward one side,” Daniel Abrams, an assistant professor at the McCormick School of Engineering and Applied Science who helped develop the model, told LiveScience.

“The most important factor for an efficient society is a high degree of cooperation,” he added. “In humans, this has resulted in a right-handed majority.”

In other words, we may have, for some reason, evolved to favor right-handedness, so anyone deviating from this may have been conditioned to use that hand primarily despite their genetic predisposition.

In fact, Judith Schmitz, one of the authors of the new study, told Business Insider that twin studies have shown the contribution of genetics for handedness is about 25%.

The new study couldn’t explain the majority of right-handedness, but Schmitz explained how bird research can show how genetics and environment can be the cause.

Read more: Introverts are not socially anxious by default, and understanding this can help them network with people more effectively

“In chicken and pigeons, a genetic factor determines the position in the egg before hatch – the embryo is curled such that the right eye is turned to the semi-translucent eggshell, while the left eye is covered by the embryo’s own body,” she said.

“Thus, the right eye is stimulated by light before hatch, whereas the left one is mostly light deprived. This combination of genetic and environmental factors (light) induces a visual asymmetry – pigeons and chicken are better in visual discrimination, categorization, and memorization of visual patterns with their right eye than with their left eye. If chicken or pigeon eggs are incubated in darkness, the development of this asymmetry is prevented.”

Why exactly people are left-handed is still a bit of a mystery – partly because left-handed people are often excluded from scientific research, experts say – and it’s hard to predict whether a child will be left or right-handed once they are born.

One thing we do know, though, is that the neurological differences between left- and right-handed people are small, and supposed behavioral or psychological distinctions have largely been debunked.

What Is Left-handedness?

Left-handedness is an individual’s preference to use the left-hand as the dominant hand to perform various tasks. In the world, about 10 percent of individuals are left-handed. Men are more likely to be left-handed than women and express the left-hand more dominantly. According to studies, between 70-95 percent of the world’s population is right-handed. Among them are ambidextrous individuals who can use either hand equally well, though it is very rare to find ambidexterity.

When it comes to handedness, there are different types.

  • Right-handedness is the most common type and the most dominant. Right-handed people are more skilled in performing tasks with the right hand. An overwhelming majority of people on the planet are right handed. As a result, most gadgets and devices are designed with the right-hand use in mind. Studies suggest that 70-95 percent of individuals have the right hand as the more dominant one.
  • Left-handedness is less common and can be found in about 10-12 percent of individuals on earth. The more skilled left-hand can present a challenge since most devices, gadgets and tools are designed for right-hand use. Men are 23 percent more likely to be left-handed than women. Over the years, the percentage of people who are left-handed has continued to rise. It is approximated that 2 percent of the world population was left-handed in 1860, 4 percent in 1920 and currently stands at 10-12 percent.
  • Mixed-handedness is the phenomenon of using both hands interchangeably when the task demands. Only about 1 percent of people can do this.
  • Ambidexterity is when a person is able to use both the right hand and the left hand equally well. Ambidexterity can be learned even though people tend to prefer using their more dominant hand to perform tasks.
  • Factors That Cause Left-handedness

    Several theories explain the development of left-handedness in humans. Prenatal development is a major factor when determining the more dominant hand after birth. Researchers have established that handedness can be predicted in the womb, where fetuses tend to prefer either left or right hand. After birth, they stick to their more dominant hand.

    Genetic factors play a major role in determining the preferred hand. Handedness is influenced by the dominant hands of the parents. If both parents are left-handed, there’s a 26 percent chance that the child will be left-handed. A right-handed father and a left-handed mother have a 22 percent chance of having a left-handed child. A left-handed father and a right-handed mother have a 17 percent chance of having a child who is left-handed.

    Division of labor is a common theory explaining the emergence of left-handedness. The brain hemisphere associated with speaking and handiwork operates in one sphere instead of it being divided. This theory asserts that left-handed people have a reversed brain division which makes the left-hand more dominant.

    It is suggested that ultrasounds may affect the brain of unborn babies which may lead to higher rates of left-handedness if the mother did receive ultrasounds during pregnancy.

    In conclusion, left-handed people are associated with higher intelligence in language and are generally a group of above-average high achievers. When it comes to health matters, left-handed people are more likely to have been born with a lower birth weight. They have an increased risk for mood disorders, dyslexia, and ADHD according to a study conducted in 2010 by Pediatrics.

    The left brain knows what the right hand is doing

    “There’s an advantage to cerebral dominance because it localizes function to one hemisphere,” he says. “Otherwise, information has to cross back and forth across the corpus callosum, and that can sometimes cause problems.”

    A strongly symmetrical brain, like Einstein’s, leaves people open to mental dysfunction, but it also paves the way for creative thinking. Researchers are exploring these unusually balanced brains and finding out why that’s the case.

    Righties rule

    About 90 percent of people are right-handed, says Corballis. The remaining 10 percent are either left-handed or some degree of ambidextrous, though people with “true” ambidexterity—i.e., no dominant hand at all—only make up about 1 percent of the population.

    That means the vast majority of people on this planet have strongly lateralized brains. That’s probably no accident, Corballis says. Early in human history, and possibly even in our pre-human ancestors, evolution delegated different cognitive responsibilities to the brain’s two hemispheres, he posits. It would be inefficient for both sides to, for example, process a person’s speech when one hemisphere can do that just fine on its own. That frees up the other hemisphere to do something else, such as sort out the speech’s emotional content.

    Researchers used to think that minor brain damage early in development caused left-handedness, he notes.

    “But if that’s true, that’s probably the minority of cases,” Corballis says. There are just too many lefties for brain damage to be the major culprit, “so we look to genetics.”

    In 2007, geneticists identified a gene on chromosome 2, LRRTM1, that seems to be present in most lefties (Molecular Psychiatry, Vol. 12, No. 12). The gene has also been linked to schizophrenia, which fits with earlier research showing that people with schizophrenia are significantly more likely to be left-handed or ambidextrous.

    Less-lateralized brains may also be linked to lower IQ scores, suggests a study by Corballis, published in Neuropsychologia (Vol. 46, No. 1). The study found that left-handers and right-handers had similar IQ scores, but people who identify as ambidextrous had slightly lower scores, especially in arithmetic, memory and reasoning.

    These results dovetail with Corballis’s previous findings that ambidextrous people also rate higher on a “magical ideation” scale, which measures people’s propensity to, for example, think that people on television are talking directly to them or that they can sense when people are talking about them (Laterality, Vol. 7, No. 11).

    The link among these three findings—the slight propensity for schizophrenia, lower IQ scores and magical ideation—may suggest that the brain is more likely to encounter faulty neuronal connections when the information it’s processing has to shuttle back and forth between hemispheres, says Corballis.

    Ambidexterous payback

    Research suggests that there might be a big advantage to a less constrained brain: It might lead to less constrained thinking.

    For years, anecdotal evidence has suggested that lefties might think more creatively than right-handers, and recent research supports this link. A 2007 paper in Journal of Mental and Nervous Disease (Vol. 195, No. 10) found that musicians, painters and writers were significantly more likely to be left-handed than control participants.

    Corballis has a theory as to why: Just as information is prone to errors as it traverses between brain hemispheres, it’s also more likely to encounter novel solutions. Righties might dismiss an idea as too radical, but nonrighties might be willing to entertain the thought nonetheless, and develop a solution that a right-hander’s brain would skip right over.

    “It’s good to have a few people in any society who think outside the square,” Corballis says.

    Left-handers are taking that creativity straight to the bank, too, says Christopher Ruebeck, PhD, an economist at Lafayette College in Easton, Pa. In a study published in Laterality, he found that lefties earn slightly more money than their right-handed peers who work at the same jobs. These results were most pronounced in left-handed college-educated men, Ruebeck says, who, on average, earn 15 percent more than righties. In fields where creative thinking is valuable, lefties might get the edge and earn more accordingly.

    “Left-handed men seem to get a higher return on their education,” he says.

    The study found this effect in men but not in women, Ruebeck adds, though he’s unsure why that might be. And because his study is one of only a few that have looked into this area so far, he cautions against overgeneralizing these results; at the moment, it remains an interesting correlation.

    Also, equating left-handedness with creativity glosses over the fact that 20 percent of left-handed people do have strongly lateralized brains and are probably no more creative than right-handers. The idea of lefties as creative types “probably refers to the subgroup of who lack clear dominance in the hemispheres,” Corballis says.

    So what’s the final verdict? Well, in a way, the human condition itself might be summed up as the balance between the brain’s asymmetries and symmetries—rationality versus creativity, novel ideas versus traditional solutions.

    “The asymmetrical brain might even represent science and the symmetrical brain, religion,” Corballis speculates. “An exaggeration, no doubt, but it’s fun to think along these lines.”

    What percentage of people are left handed?

    Ever signed for a delivery and had the driver ask if you’re a lefty? Apparently we’re still that much of a rarity that people feel the need to point it out to us every time they notice.

    I’m not having a go, I do it myself. All the time…

    Last week at work the purchasing team ordered a bunch of Fender merchandise, including (for some reason!) this ridiculous anime lunchbox. Rather than asking why in the hell we were stocking a Fender lunchbox (like everyone else in the office), I proudly pointed out that the girl on the front was playing a left handed guitar.

    So apparently it’s still a novelty even to me. A guy who is left handed, plays guitar lefty, and runs a lefty guitar website…

    What makes for the fascination? Just how many people are left handed exactly?

    Check out the handy, dandy infographic below (click to enlarge!), or keep reading to find out.

    What Percentage of People are Left Handed?

    Roughly 12% of the world is left handed.

    This figure is averaged from studies undertaken in North America and Western Europe. In these developed countries being left handed is less likely to be discouraged due to social stigmas, which should result in a less skewed overall number. Although it should be noted that left handed discrimination does still occur in these countries, such as this well publicised example in the USA in 2015.

    Right Handed (~87%). I’m sure you didn’t come to this article unaware that right handed people make up the majority of the population. It is estimated that right handed people amount to roughly 87% of the world.

    Left Handed (~12%). The second most common handedness type, studies show that on average us lefties make up around 12% of the population. Although this does vary depending on location, as in some countries being left handed may still have a social stigma attached to it. For example Taiwan (5%), Japan (4.7%), and Korea (2%) all have a much lower population of lefties. Scroll down a little further to see the lefty representation broken down by country.

    Ambidextrous (<1%). An ambidextrous person is able to perform any task equally well with either hand, although they do still tend to favor their dominant side. Truly ambidextrous people are incredibly rare, and are estimated to make up less than 1% of the population.

    Ambivelous (<1%). An ambivelous (or ambisinister) person is the exact opposite of an ambidextrous person, finding it generally awkward to use either hand to undertake tasks.

    Age is a Factor

    Even until recently, being left handed was still discouraged in many developed countries. We can see this when we look at the number of lefties in different age groups in North America. Only 6% of over-65s identified as being left handed, whereas a whopping 15% of under 30s said the same.

    Check out the graph below which shows the percentage of lefties broken down by year. These results were taken from a large study by Gilbert and Wysocki (Hand Preference and Age in the United States, 1992) which included over 1 million people. The increased number of people identifying as being left handed is almost certainly due to modern society becoming less conservative.

    On top of this, it is estimated that amongst older generations some 6-8% of right handed people are actually natural left handers, but were forced into writing right handed due to social pressures.

    Considering the results based on age, it would seem very likely that the overall percentage of people identifying as being a lefty will continue to increase over time.

    How Many People Are Left Handed In Other Parts of the World?

    The figures above are taken from a select few countries, but what about the rest of the world? Check out the graphic below to find out!

    Data for European countries was taken from a large internet study by McManus and Peters (Handedness in Europe: analysis of data from the BBC internet study). Information on other countries was sourced from various other bodies of research.

    It’s clear that in countries with a more formal culture, the rate of left-handedness is much lower. It has been suggested that the more complex writing style in many Asian countries is a major reason why the numbers are so much lower.

    Men Versus Women

    Lefties are not created equally! According to a 2008 study (Sex Differences in Left-Handedness: A Meta-Analysis of 144 Studies), a left handed person is 23% more likely to be male than female. This means that for every 4 left handed women, there should be roughly 5 left handed men.

    One possible explanation for this uneven split is that girls are more likely to conform to social norms. It has also been suggested that there may be genetic factors, which you can read about below.

    The Chances of Having a Left Handed Child

    According to a 2009 study by Llaurens, Raymond and Faurie (Why are some people left-handed? An evolutionary perspective), the chances of having a left handed child are as follows:

    I’ve averaged these results out for simplicity and displayed them in the graphic below.

    Another interesting factoid I stumbled across was that two left handed parents are twice as likely to produce twins!

    Is There A Place Where 100% of People Are Lefties?

    Yes! Well, kinda… In the small town of Left Hand, West Virginia, USA, technically…everyone is a left hander!

    Further Articles You Will Love

    • How much of a lefty are you? Take our 60 second test and find out!
    • 25 Amazing Facts About Lefties
    • Gift Ideas That Left Handed People Will LOVE
    • The Survival Guide for Living Lefty in a Right-Handed World
    • The Causes and Consequences of Left-Handedness

    7 Scientific Reasons Left-Handed Women Make The Best Wives

    Lefties of the world: UNITE!

    This past year, I discovered boxing. And while now I surprise myself with how hard I can really throw a punch, it didn’t start off so rosy. In fact, in my very first boxing class, I was so confused by my hand and foot positioning that I nearly snapped at the instructor (who I now consider a friend and inspiration).

    What finally helped was saying the three words I’ve been saying since I was five years old: “I’m a lefty.”

    About 10 percent of the world’s population are lefties, and while we are rather rare, we also have some pretty big advantages over you right-handed folks. I take pride in using my Southpaw, not only because of my pretty killer left cross, but also because it gives me a unique perspective on a lot of things. (Even if I’m constantly washing my hands because of that dreaded side-hand smudge that comes from using a pen and paper as a lefty.)

    Here’s why it’s pretty cool to be a left-handed person, backed by science:

    1. We can kick your ass.

    The next time you get into an argument and need someone to have your back, turn to your left-handed bestie.

    A study at University of Montpellier in France followed nine primitive societies on five continents and discovered that more lefties got into violent encounters than their right counterparts. The kicker? We started the fights — and we ended them — usually having the upper (left) hand throughout.

    photobucket

    2. We use more of our brain than righties.

    If you’re right-handed, you lean on the left hemisphere-dominant side of your brain, whereas us lefties can move between the right and left side more fluidly. Why does this matter? This makes us a little more creative and can help us recover from some medical conditions that affect our brains (like a stroke, for example).

    3. We’re better able to see underwater.

    I always told my mom I wanted to be Ariel from The Little Mermaid. She might not have realized it then, but it could have been an indicator that I’d be left-handed. Because of how the left-handed brain works, we adjust easier to an unfamiliar world — being underwater, for example — than righties.

    If you live by the sea or enjoy swimming as a lefty, you’ll most literally feel like a fish in water and less afraid.

    giphy

    4. We have a greater chance to be brilliant (and have higher IQs!)

    Did you know that 20 percent of all Mensa members — largest and oldest high IQ society in the world — are left-handed, even though only 10 percent of the population identify as lefties? Just as an example, four of the five original designers of the Macintosh (Apple) computer are listed as lefties.

    Scientists aren’t sure why we’re so damn smart, but they hypothesize that it’s because we’re able to take a lot of information in at one time, process it faster and discuss it. It takes righties more time and brain energy to do the same.

    5. We’re excellent multitaskers.

    At this given moment, I’m texting with my boyfriend, researching for this article, writing it, listening to Spotify, and have a roasted chicken in the oven. It might just be my inability to ever do just one thing at once, or it could be that I’m left-handed.

    My brain has been forced to think faster over time because I live in a right-handed dominated world, so I have to quickly translate instructions so they make sense for my left-handed preference.

    tumblr

    6. We pass our left-handed genes onto our children.

    OK not really, but apparently it runs in families. Like the Royal Family, for example: Queen Elizabeth, Prince Charles and Prince William are all left-handed. Princess Charlotte and Prince George have a bigger chance of being lefties too, just because dad is in their blood line and genes.

    7. We discover our sexuality sooner.

    If you’re a lefty and you lost your virginity before your right-handed besties, you can blame your dominant hand for that. Yes, according to research, lefties reach puberty four to five months earlier than righties.

    tumblr

    Happy Left-Handers Day! Why are lefties so rare?

    Thursday marks International Left-Handers Day, a holiday to celebrate the 10 percent of the population that struggles with spiral notebooks, scissors, and elbow bumping every day.

    Researchers have disproven a plethora of popular myths about left-handed people, such as their supposed higher levels of creativity and introversion and the belief that they die earlier than their right-handed counterparts. But there’s still a lot that scientists don’t know about lefties, including the definite origin of left-handedness.

    A common misconception is that handedness is a result of nurture rather than nature, so many left-handed children in the past were forced to “correct” themselves by learning to write and eat with their right hand.

    However, research in recent years – such as one 2013 study which found that variants in the gene PCSK6 contributes to handedness determination – shows that there is likely a genetic component to handedness as well. The fact that a couple’s chances of having a left-handed child is bumped up from 10 percent to 25 percent when both parents are lefties confirms that your handedness is determined before you’re even born.

    Other animals, including polar bears and chimpanzees, have also demonstrated a preference for one hand over the other when searching for food or using tools. But these populations are generally divided 50/50 between righties and lefties, making humans the only species with such a strong imbalance.

    This 9-to-1 ratio of human handedness has remained constant since the era of cavemen, according to archaeological evidence dating back around 500,000 years. Given the disadvantage left-handed people have living in a world of tools made for right handed-people, it might seem unlikely that this trait would live on.

    However, one theory known as the “fighting hypothesis” suggests that lefties have stuck around thanks to their advantage in physical competitions or combat. Thanks to the rarity of left-handedness, lefties are used to competing physically with righties, but right-handed people are usually thrown for a loop when faced with a left-handed opponent.

    Professor Daniel M. Abrams, who studies the physics of social systems at Northwestern University, points out in a TED-Ed talk that 50 percent of the top hitters in baseball are left-handed; being in the minority proves to be a great advantage when going up against pitchers who are used to throwing to righties.

    In terms of evolution, this advantage would normally cause the number of lefties to grow until the ratio of handedness was 50/50, Abrams says. However, the advantages of the fighting hypothesis are balanced out by the difficulty left-handed people have when using tools made for righties, and the high number of accidents that result in their misuse of these tools.

    Get the Monitor Stories you care about delivered to your inbox.

    Today, the pros and cons of being a lefty in Western societies are relatively insignificant, and usually don’t play a role in life or death situations. Five out of the past seven US presidents have been left-handed, including Barack Obama, and other famous lefties include Oprah Winfrey, Robert Redford, Lady Gaga, and Morgan Freeman.

    Happy International Left-Handers Day!

    This Is How Many People Are Left-Handed

    From scissors to desks to baseball mitts, there are constant reminders that the world just isn’t designed for left-handed people. While being a lefty can make a person feel left out, southpaws aren’t as unique as you might think.

    Approximately 10 percent of the population is thought to be left-handed. That means there could be upwards of 700 million total lefties around the globe. In fact, being a lefty is significantly more common than having blue eyes, red hair, or identifying as a member of the LGBT community.

    So, what causes someone to be left-handed in the first place? A DNA quirk? An inherited trait? A curse? The short answer is that scientists simply aren’t sure why some people are singled out to be southpaws. However, while science hasn’t pinpointed a specific gene that causes people to be left-handed, there may be some significance to this feature. In fact, during a 2015 presentation to London’s Royal Society, Dr. Silvia Paracchini, a human geneticist from the University of St. Andrews, revealed that there are differences in the brains of left- and right-handed individuals.

    Left-handed individuals have significantly more nerve fibers in their corpus callosum, which divides the brain’s left and right hemispheres. A lefty has about 11 percent more nerve fibers in this strip of the brain than a righty. As such, leftys’ brains share information between hemispheres at an elevated pace.

    So, while you may never write comfortably in a spiral-bound notebook or find using a manual can opener easy, at least you’ve got plenty of brainpower that can help you find solutions to those lefty conundrums. And when you want to know more about the hows and whys of the world, the 50 Awesome Facts About Everything might just surprise you yet.

    To discover more amazing secrets about living your best life, to sign up for our FREE daily newsletter!

    About the author

    Leave a Reply

    Your email address will not be published. Required fields are marked *