Being a leftie has a genetic component, is linked to better verbal skills and is associated with a lower risk of Parkinson's disease, according to a new study published in the journal Brain.
Left-handed people are said to be good at complex reasoning, resulting in a high number of lefty Noble Prize winners, writers, artists, musicians, architects and mathematicians. According to research published in the American Journal of Psychology, lefties appear to be better at divergent thinking.
But other research suggests that there are probably dozens of genes that play a role in determining whether we end up writing with our left hand or our right. On top of that, other studies have linked factors such as oestrogen levels and birth position to varying levels of left- and right-handedness.
Left-handed and ambidextrous people are more susceptible to negative emotions, including anger. A small study published last year in the Journal of Nervous and Mental Disease found that the brains of lefties process emotions differently than those of righties, with more communication between the brain's two halves.
The idea that left-handed people are more intelligent than right-handers is a myth. There have been lefty geniuses in history like Leonardo da Vinci, but this is not part of a larger pattern.
Our confidence intervals at a 95% confidence level show that the average IQ for a left handed person is between 117.73 and 127.19 and for a right handed person it is between 109.9 and 123.5.
Babe Ruth. The Babe is probably the most famous left-handed slugger of all-time.
Overall, individuals with ADHD had a 27.3 percent chance of being either left-handed or mixed-handed compared to 18.1 percent in the general population. So the results suggest that the effects are smaller than for the autism spectrum, but generally go in the same direction.
Wright and Hardie (2012) found that left-handers reported higher levels of state anxiety but there was no difference in trait anxiety. They also demonstrated that when Trait Anxiety was controlled for, left-handers still showed a higher level of state anxiety compared to right-handers.
The other hand, comparatively often the weaker, less dextrous or simply less subjectively preferred, is called the non-dominant hand. In a study from 1975 on 7,688 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.
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.
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.
If two parents are right-handed, their offspring has a 10% chance of being left-handed. However, if one or both parents are left-handed, the chance of their child being left-handed becomes higher at 18 to 22% and 27%, respectively.
Because we write from left to right, right handers pull the pencil, writing away from their body while left handers have to push the pencil, writing towards their body. Teaching left handed people to write the same way as right handed people can make handwriting slow, uncomfortable and messy.
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 conclusion, there is no significant difference in the speed of writing between left-handers and right- handers in dominant hand use. However, in the change from dominant hand to non-dominant hand, left-handers were faster.
In a study controlled for average intelligence (IQ), sex, and age, roughly 62% of those on the autism spectrum were not right-handed (i.e., they were more likely to be either left-handed, mix-handed, or of unclear handedness) compared to only 37% of the control sample population.
Researchers have not yet found a genetic link between dyslexia and handedness and individuals with dyslexia, a learning difficulty that affects reading, writing and spelling abilities, are split 50:50 between right and left-handedness. However, there are fewer left-handed people in the world.
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.
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.
His wife, Queen Elizabeth, the Queen Mother, was also left-handed. The Queen Mother didn't pass her left-handedness on to her daughter Queen Elizabeth II.
Eleven percent of the population is born left-handed, and if they seem different, it's because they are! Learn six tips for raising a left-handed child.