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.
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.
This is often associated with enhanced intuition, emotion, imagination and creativity. Left-handed people are also believed to be better at thinking outside the box and problem-solving, which could be a big advantage as your child approaches school age.
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.
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 study of “handedness” by the National Bureau of Economic Research reveals the earnings power of highly educated left-handed men was 15 percent greater than that of their right handed peers. Leftie women showed no increase in their earnings.
'If a lefty writes with his right hand it's bad, because we're changing the hand but not the leading eye or the leading foot. ' So a child who has had his hand changed is more prone to distraction; he absorbs information more poorly. As a result, he can become more irritable.
Researchers who study human hand preference agree that the side of the preferred hand (right versus left) is produced by biological and, most likely, genetic causes.
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.
Newborns are born with equal ability in their left and right sides, but over the next few years the adult pattern for handedness will start to show. Even though adults can train their weaker side, they can never switch the preference for a certain hand! A newborn baby doesn't show any hand preference.
The “American Heritage Dictionary of the English Language” cites the conventional wisdom that the word “southpaw” originated “from the practice in baseball of arranging the diamond with the batter facing east to avoid the afternoon sun.
First Chronicles 12:2 seems to reference bowmen who were ambidextrous. When the Bible refers to left-handed people, it speaks of left-handedness as an advantage, not a weakness. While it is not as honorable as sitting at someone's right hand, sitting at the left hand is still a position of honor.
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.
Centuries ago, the Catholic church denounced left-handed people as servants of the devil. For generations, left-handed Catholic children were forced against their will to become right-handed. Just a few short decades ago in Japan, the fact that your wife was left-handed could be cited as grounds for divorce.
Left-handedness — sometimes called "sinistrality" — means you prefer to use your left hand rather than your right hand for routine activities, such as writing. Most people who have studied left-handedness believe that approximately 10 percent of the people in the world are left-handed.
Various surveys have found that the highest incidence of left-handedness is in Western countries. The Netherlands, the USA and Canada lead with around 13 per cent of the population being left-handed and the UK is only just behind.
Researchers have suggested a link between handedness and ability with mathematics. This link has been proposed by Geschwind, Galaburda, Annett, and Kilshaw. The suggested link is that a brain without extreme bias towards locating language in the left hemisphere would have an advantage in mathematical ability.
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.
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.
To be left-handed, both copies would have to be the left hand gene. That also means two lefties would always have left-handed children. This is not the case for your family or lots of others either. For example, if both parents are right-handed, there is a 1 in 10 chance of having a left-handed child.
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.