While this is still contested, studies have found that artists like painters, musicians and even architects are mostly left-handers. Right and left-handed people deal with tasks and memory in different ways. Left-handers are known to efficiently multitask as they look at the tasks as a whole.
As handedness is a highly heritable trait associated with various medical conditions, and because many of these conditions could have presented a Darwinian fitness challenge in ancestral populations, this indicates left-handedness may have previously been rarer than it currently is, due to natural selection.
Genetic Roots
But it wasn't until 2019 that they identified differences in parts of the DNA of left- and right-handers. The study, which also analyzed brain scans of 9,000 British subjects, found that in lefties, the parts of the right and left sides of the brain that process language work in better tandem.
In a 1996 study, Harvard Medical School researchers found that orthopedic surgeons, librarians and mathematicians were mostly right-handed while attorneys and architects were, as a group, “either the least right-handed or the most left-handed.” Other studies have shown that there are more left-handed people working as ...
According to IFL Science, those who have a left-hand preference "on average, [have] a more developed right-brain hemisphere", which helps when it comes to processing and understanding spatial awareness and mental representations of objects.
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.
They also demonstrated that when Trait Anxiety was controlled for, left-handers still showed a higher level of state anxiety compared to right-handers. This supports the notion that state anxiety differences are the most appropriate measurement to record when examining the reaction to a particular situation.
Left-Hander Superstitions and Terms
Many people believe that the devil is left-handed. The Latin word for left, sinister, also means unlucky, evil, and suspicious. The French word for left, gauche, also means clumsy. A left-handed compliment is an insult.
Research shows that left-handed people are more likely to have a more developed right hemisphere of the brain, which is responsible for creative tasks. The right hemisphere of the brain is linked to creativity because it governs nonverbal, intellectual, holistic, intuitive, and imaginative functions.
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.
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.
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.
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.
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.
The same brain differences that contribute to left-handedness also contribute to psychotic disorders. But there's a bright side. Only about 10% of the population is left-handed, yet lefties make up as much as 40% of cases of psychotic disorders.
The skill set and athleticism required to play shortstop position is rarely found in youth baseball kids. You are right on that lefties should not play baseball shortstop or 3rd base. The only positions lefty baseball players should play are pitcher, firstbase and outfield positions.
Why? A lefty's curveball can be a nasty pitch against right-handers, but it can also throw lefties off too. The curve can head straight for the batter then break at the last second, causing the hitter to instinctively back off. Left-handed hitters can have a particularly hard time with lefty pitchers throwing sidearm.
Results showed no significant difference in the speed of writing between left-handed users and right-handed users, though the right-handers were slightly faster. When the right-handers and left-handers used their non dominant hand, left-handers were faster.
Overall, the intelligence differences between handedness groups in the general population are negligible.
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.
-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.