By: R. Liaw
There is a good 90% chance that you are right handed. Am I right?
But why? Throughout history, left - handedness has been the cause of many deaths, disagreements and prejudice. For example, if you were a lefty in the 15th century, you would be accused of witchcraft and burned alive, simply because of this unusual trait (some used to say that left – handed people had been “touched by the devil”).
In the 1800s, science kicked in and people started to have scientific and logical theories instead of just blaming it on “demons”. Some of them were pretty ridiculous since the researchers did not conduct any specific experiments or tests, -- but they were way better than the ones from 400 years prior. One theory explained that internal organs were arranged differently for lefties, changing the center of gravity in their bodies to the right side, building up muscles on the left. Another theory suggested that the few mothers nursed and carried their babies with their left arms caused their newborns to imitate their own movements. Fast forward to the early 1900s, and school children were beaten up and forced to write with their right hands. Some people even tied up children’s left arm so they would not be able to use it!
Some animals like chimpanzees and polar bears also have preference between one hand or the other. However, the spilt in their population is fifty – fifty. While humans are the only known species which show distinct preference toward the right or lest hand. But why is this? In the 21st century, scientists have finally come up with newer theories that have been tested and experimented with. Basically, there are many factors that contribute to this phenomenon. Those being: genetic, prenatal hormone exposure, prenatal vestibular asymmetry, division of labor, ultrasound, and environmental. It has been proved in a study that if both parents of a child are left handed, there is a 26% chance of that child being a lefty. Another study has proven that while 25% of variance in handedness are from genetic factors, the remaining 75% is all due to environmental factors.
In 1976, the Left handers club was founded to fight for lefty’s rights. They even ended up creating International Left Hander’s day, which is held annually on August 13th.
While, we cannot explain fully the mystery of handedness yet, every day, science unravels the secrets to why and how some of the world’s weirdest phenomenon are what they are.
Image by: GETTY IMAGES, http://health.usnews.com/wellness/articles/2016-08-31/the-health-benefits-of-expressive-writing