Are you a lefty? Do you ever wonder why there are so few left-handers? Are you the only one in the family who is left-handed? We’ll look at the percentage of left-handers in the world and the reasons scientists think left-handers exist. Plus, why the percentage numbers have gone up since 1860.
Why Has the Number of Left-handers Gone Up?
Most research claims left-handedness is a person’s preference to use the left hand as their dominant hand. I don’t understand why they say preference or choice. I, as a left-hander, am not left-handed as a choice or preference. I am left-handed. I was born left-handed it’s not a choice for me. It’s what and who I am. Do right-handers choose to be right-handed? I bet not, and I bet they would say the same thing that right-handed is who they are. Anyway, that’s my two cents worth. I’ll share some of the research findings.
Twenty-three percent more men are left-handed than women. Left-handers make up ten to twelve percent of the world population. Right-handers make up seventy to ninety-five percent of the world, and a small percentage are ambidextrous or mixed-handed. These percentages seem a bit skewed as they can add up to over one hundred percent, but these studies were done over years, so the rate can rise or drop in any given year.
Left-handers are more comfortable throwing a ball, writing, and doing other manual tasks with their left hand. Most people use their right hands for those tasks. A few, however, are ambidextrous, which means they can use both hands equally well. Plus, some people switch hands for specific tasks, called mixed-handedness.
Some estimates show that left-handers were rarer years ago, consisting of two percent of the population around 1860 and four percent about 1920. This idea may have come about because it was once a popular choice to force left-handed children to become right-handed. There are several reasons for this choice. These days left-handedness is more acceptable with less stigma attached. These days there are also more tools made explicitly for left-handers as well. Though, I grew up making do with those tools made for right-handers.
Why Are Some People Left-handed?
Why are some people lefties? Prenatal development is a significant factor in whether a child will be left-handed. The research established that handedness could be predicted in the womb. The fetus has a preferred dominant side. Perhaps that’s where the preference talk comes in. When the child is born, they usually stick to their prenatal dominant side
Genes play another significant role in handedness. The parents’ dominant hands influence the dominant hand of the child. There is a twenty-six percent chance that a child will be left-handed if both parents are left-handed. A left-handed mother and a right-handed father have a twenty-two percent chance of having a left-handed child. A lefty father and a righty mother have a seventeen percent chance. I wonder what my parent’s percentage was? My dad was ambidextrous, and my mom is right-handed. I always just thought I was the oddball.
Research also suggests that ultrasounds may affect the brain of unborn babies leading to higher rates of left-handedness. Could this be the case? What about those babies born before the invention of ultrasound as I was?
Some scientists believe that being left-handed is because of some deeper, evolutionary reason. They may be rare because of the balance between cooperation and competition in human evolution. Left-handers appear to be rare because of the balance in collaboration over competition. It makes sense that more people with a particular handedness will cooperate better over those with different handedness. A righty can work or collaborate with another righty easier than a righty with a lefty and vice versa.
Northwestern University researchers report that a high degree of cooperation plays a vital role in the rarity of left-handedness. These researchers developed a mathematical model that shows the low percentage of lefties is due to the balance between competition and cooperation in human evolution.
Graduate student Mark J. Panaggio, and Professor Daniel M. Abrams confirmed the hypothesis that social behavior is related to population-level handedness using real-world data gleaned from competitive sports.
Abrams stated that “The more social the animal—where cooperation is highly valued—the more the general population will trend toward one side.” Abrams is an assistant professor of engineering sciences and applied mathematics at the McCormick School of Engineering and Applied Science.
Cooperation for sharing the same tools favors same-handedness. Physical competition, such as sports, favors the unusual. In this case, left-handers being with right-handers. A left-handed fighter would have an advantage over a right-handed fighter because the right-handed fighter wouldn’t expect his opponent to hit with the left hand.
With this information, Abrams stated that “The accuracy of our model’s predictions, when applied to sports data, supports the idea that we see the same effect in human society.”
It appears that handedness is partially genetic and partially environmental.
Conclusion
Even with many studies done to see why left-handers exist, no one yet has a definitive answer. Is it genetics? Is it our environment? The environmental idea seems a bit odd to me, considering how much our environment has changed over the many years. What do you think is the reason behind left-handedness compared to right-handedness? Do you have a theory? Please leave a comment below. We’d love to hear from you.