Odds are at least 8 percent of you reading this would write it left-handed. Actually, that’s not quite true; according to Science Daily, a few lefties use the right to write, while favoring the left for most other things, although such task-based cross-dominance is rare.
Today is International Left-Handed Day.
Being a leftie in a right-dominant world can be challenging — scissors and those funny-shaped student desks, for example. Centuries ago, misunderstood southpaws were persecuted as evil. The word “sinister” derives from the French senestre (contrary or to the left) and Latin sinister (left).
Yet there are advantages. The roughly 1 in 10 people (8 to 15 percent worldwide) who are “southpaws” include notable VIPs: Presidents Obama, Reagan, and Clinton; Alexander the Great; Queen Victoria; Joan of Arc; David Rockefeller; and author H.G. Wells (War of the Worlds). Before you add Einstein, the persistent claim of his left-handedness is somewhat disputed by photos of him writing with his right.
Maybe the Einstein claim was the source of the idea that lefties are more intelligent. Studies do suggest that at minimum, certain characteristics seem to go with one hand or the other.
Twins. Compared with the general population, lefties occur more frequently in identical twins (who don’t necessarily have the same dominant hand), as well as certain neurological disorders such as epilepsy, Down syndrome, autism, and dyslexia.
Animals are lefties, too. Cats and dogs favor the right or left paw, with about a 50-50 split. According to the Journal of Human Evolution, chimps and gorillas are more like humans, tending as a group to favor the right. Yet orangutans favor the left.
Cavemen. French researchers and University of British Columbia psychologist Stanley Coren described ancient European cave paintings depicting spears and other objects in right hands, along with cave-painting artists’ “signature” right-handprints.
Creativity. Einstein notwithstanding, leftie research correlations include a greater tendency to be successful in visual-spatial fields such as architecture, art and design, with more righties represented in the traditional sciences, according to Coren.
Genes. Can we can teach ourselves to be ambidextrous? Doubtful, although some claim success anyway. Research indicates only 1 percent of the population can use either hand equally, and a handedness-gene might be passed through the paternal line.
The brain. Much focus of leftie research has been centered on the brain. According to scientific studies highlighted by the Nova report, “Inside the Mind of a Left-hander,” the brains of left-handers may process tasks a little differently.
Take differences in the brain’s motor cortex, which is responsible for voluntary movement. Researchers in the Netherlands found that in righties, the left part of the motor cortex is more developed than the right side.
While a similar imbalance was also found in left-handers, it’s far less pronounced — there’s less cortex imbalance in lefties. That may be why it’s easier for lefties to use the opposite hand than it is for righties.
Or the spinal cord? International research published in the Feb. 1, 2017, issue of eLife noted asymmetrical gene activity in the spinal cord, before the motor cortex is active. For the first 15 weeks of fetal growth, the motor cortex and the spinal cord aren’t connected yet, but right- or left-handedness has already been determined.
In other words, the fetus can already start movements and chooses a favorite hand before the brain starts controlling the body.
External influence. The same study also concluded that this could come down to epigenetics — gene expression. Gene expression is how changes are effected by outside influences (what the pregnant mother experiences or what her body goes through, for example) rather than in the genes themselves. That likely continues throughout life, as socially righties are still favored.
Baseball. Why the nickname, “southpaws?” In major ballparks, they say, the pitcher’s mounds face west, to avoid the setting sun in a batters’ eyes. Left-handed pitchers thus threw with the “south” hand. Official Rule 1.04 states, “It is desirable that the line from home base through the pitcher’s plate to second base shall run East-Northeast.”
Sholeh Patrick is a columnist for the Hagadone News Network. Contact her at Sholeh@cdapress.com.