Right-handed people are more skillful with their right hands. Studies suggest that approximately 90% of people are right-handed. Left-handedness is less common. Studies suggest that approximately 10% of people are left-handed.
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.
Hand preference probably arises as part of the developmental process that differentiates the right and left sides of the body (called right-left asymmetry). More specifically, handedness appears to be related to differences between the right and left halves (hemispheres ) of the brain.
-Counting how many people are left-handed is more difficult than it looks, because of variations in preference and skill from task to task and because of left-handers having been forced to write with their right hand, but the best estimate we have is that roughly 10% of the world population is left-handed.
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.
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.
If both parents were left-handed, the chance of their offspring also being left-handed was highest: 26 percent. This indicates that children of two left-handed parents have a higher chance of being left-handed, but also that three-quarters of them are still right-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.
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.
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.
For example, left handedness determined by grip strength has been shown to be associated with poorer cognitive function [12], whereas left handedness, via self-report, has been shown to be associated with better memory and attention task performance [13].
Sometimes people who are left-handed are called many different things, “Southpaws”, "Lefties", and other simply mean names, like "Weird" or "Strange".
Some children experience them from early stages of literacy education, while others occur at a later stage while reading texts. In comparison to right-handed people, left-handed people are 2.5-3 times more likely to have difficulty in mastering written speech -- in both writing and reading.
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). Given the low incidence of left-handedness in general, this 2 percent increase is quite a substantial difference.
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.
Conclusion: 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.
Left-handers – we know from our own surveys that 74% of left-handers eat with a knife and fork in the “right-handed” way – with the fork in their left hand and feeding themselves with the left hand.
His left-handedness shone through when he played tennis and held the racket in his left hand. 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. Prince William is also a lefty.
Research suggests that between ten and twelve percent of the world's population is left-handed. Even though being left-handed might mean struggling with right-handed scissors from time-to-time, there are plenty of reasons being a lefty is pretty cool!
It's no surprise, then, that numerous left-handers have found a home at the piano keyboard, including some of the most famous talents of the 20th century—Vladimir Horowitz, Arthur Rubinstein and Glenn Gould—along with stars of today such as Daniel Barenboim and Hélène Grimaud, to name a few.