The authors found that the male to female odds ratio was 1.23. This indicates that if females had a chance of being left-handed of exactly 10 percent, males would have a 12 percent chance (the exact percentages vary a bit depending on geographical region).
In a study from 1975 on 7688 children in US grades 1-6, Left handers comprised 9.6% of the sample, with 10.5% of male children and 8.7% of female children being left-handed.
One biological effect on hand preference is known to be sex, with males more likely to be left-handed than females2,14. For example, in a U.S. dataset aged 10–86 years, the proportion of non-right-handers among 664,114 women was 9.9%, versus 12.6% among 513,393 men2.
Although the percentage varies worldwide, in Western countries, 85 to 90 percent of people are right-handed and 10 to 15 percent of people are left-handed. Mixed-handedness (preferring different hands for different tasks) and ambidextrousness (the ability to perform tasks equally well with either hand) are uncommon.
Ethnic differences in handedness are related to geographi- cal differences, with left-handedness generally being more common in White, Asian and Hispanic populations – a differ- ence seen both in the UK, and historically in the United States, where the difference between ethnic groups has grown smaller during the ...
McManus which found that the Netherlands has one of the world's highest prevalences of left-handedness at 13.23 percent. The United States isn't far behind with a rate of 13.1 percent while neighboring Canada has 12.8 percent. Elsewhere, rates of left-handedness are far lower and China is a good example.
A single gene might be passed from parents to children to influence which hand a child favours. If a particular version of this gene is inherited, the child may be more likely to be left-handed, depending on reinforcement and other environmental influences.
However, post-hoc exploration of their and other sets of data has shown that there is an apparent tendency for left-handedness to be more prevalent in the period March-July than in the period August-February. The present work tested this seasonal hypothesis prospectively among university students.
Left-handedness occurs in about 8% of the human population. It runs in families and an adoption study suggests a genetic rather than an environmental origin; however, monozygotic twins show substantial discordance.
In fact, one of the more unusual hypotheses to explain the rarity of left-handedness is that a genetic mutation in our distant past caused the language centres of the human brain to shift to the left hemisphere, effectively causing right-handedness to dominate, Alasdair Wilkins explains for io9 back in 2011.
But handedness has its roots in the brain—right-handed people have left-hemisphere-dominant brains and vice versa—and the lefties who claim Einstein weren't all that far off. While he was certainly right-handed, autopsies suggest his brain didn't reflect the typical left-side dominance in language and speech areas.
“Most left-handers seem to have similar language processing to right-handers,” Grimshaw says. For other one-sided brain functions, such as attention, emotion, music, and face perception, she says, there are less data. “But for the most part, left-handers do not differ obviously from right-handers.
Princess Diana was right handed; however, like many Royals, she carried her handbag in her left hand. This was done to keep her right hand free for greeting others.
For example, if both parents are right-handed, there is a 1 in 10 chance of having a left-handed child. If the father is left-handed, the odds are 2 in 10. If the mother is left-handed, the odds rise to 3 in 10.
Because a large majority of words on the qwerty keyboard are typed solely with the left hand (around 3,000 words with the left hand, but only about 400 with the right), left handers are likely to be faster typers since they're using their dominant hand.
Lefties make up only about 10 percent of the population, but studies find that individuals who are left-handed score higher when it comes to creativity, imagination, daydreaming and intuition. They're also better at rhythm and visualization.
Special or not, lefties are born, not made: Genetics are at least partially responsible for handedness. Up until last year, it was assumed that hand preference comes from asymmetrical genes in the brain—two hands, two brain hemispheres, one is dominant.
A 2011 study from the American College of Chest Physicians suggested that left handers have significantly higher chances of developing periodic limb movement disorder (PLMD). This disorder is characterized by involuntary, repetitive limb movements that happen while you sleep, resulting in disrupted sleep cycles.
Researchers have not yet found a genetic link between dyslexia and handedness and individuals with dyslexia, a learning difficulty that impacts on reading, writing and spelling abilities, are split 50:50 between right and lefthandedness.
In their analysis of 144 handedness and brain laterality studies—accounting for a total of nearly 1.8 million individuals—University of Oxford psychologists Marietta Papadatou-Pastou, PhD, and Maryanne Martin, PhD, found that males are about 2 percent more likely to be left-handed than females.
In support of this, many studies have found that left-handed men are overrepresented among modern professional fighters, but studies typically find no difference in fighting success between left and right-handed fighters.
In Japan, about one out of every ten people is left-handed. Therefore, left-handed people are the minority in society.