Does One's Handedness Determine Intelligence? Impressive Lefty Icons Improve Image of Left-Handed People

Handedness or hand preference is a complex trait influenced by genetics, environment, and chance. According to Medline Plus, only about 10% to 15% of people in Western countries are left-handed while the majority of the population are right-handed. On the other hand, mixed-handedness and ambidextrousness are uncommon.

Although left-handed people only make up a small portion of the population, many historical and contemporary icons are lefties. According to a 2019 report, some of these icons are Barack Obama, Bill Clinton, George H.W. Bush, Leonardo da Vinci, Michelangelo, Paul McCartney, Nikola Tesla, Oprah Winfrey, Bill Gates, and Steve Jobs.

These are impressive people that left a mark on their respective field. But could this also mean that left-handers are smarter than right-handers?

(Photo : Pixabay)
Does One's Handedness Determine Intelligence?: Impressive Lefty Icons Improves Image of Left-Handed People

Are Left-Handers Smarter?

Live Science cited one research published in 2017 in Frontiers, titled "The Relationship between Handedness and Mathematics Is Non-linear and Is Moderated by Gender, Age, and Type of Task," which showed that left-handed students in the study had a significant edge in solving more difficult math problems.

So, how does handedness affected a person's mathematical ability? According to a 1995 meta-analysis of 43 students published in Psychobiology, left-handers have larger corpus callosum than right-handers.

This is a thick bundle of nerve fibers that connect and sends signals between the left and right hemispheres of the brain. Giovanni Sala, an assistant professor at Fujita Health University's Institute for Comprehensive Medical Science, said that there is a possibility that the stronger connection corpus callosum has on the two hemispheres makes left-handed people have stronger spatial abilities that are connected to mathematics.

However, Sala also told Live Science that left-handedness could be an advantage or disadvantage because it could be caused by some kind of brain damage in the left hemisphere that forced the right hemisphere to take over.

This could have led the person to predominantly use their right half hemisphere that controls the left side of the body, leading to left-handedness. This condition is called pathological left-handedness, which may also lead to learning difficulties.

On the other hand, Psychology Today reports that studies have shown no significant difference in the IQ scores between left-handed people and right-handed individuals. IQ differences between the two groups are extremely small that they are negligible in the general population. Therefore, the jury is still out whether lefties are smarter than righties.

ALSO READ: Are You a Lefty? Scientists Explain Why Only 10% of People Are Left-Handed

Left-Handedness Seen As Negative Trait

In history, left-handedness was seen in a negative light. There was even a campaign in 1936 to prevent and correct left-handedness because it was seen as a serious problem comparable to pneumonia, according to Live Science.

Left-handers were bombarded with prejudice in which was associated with negative things while right-handedness is seen in a good light. For instance, having "two left feet" is a bad thing, but being the "right-hand man" is good.

The word "left" was simply linked to being weak or broken, while the word "right" is given the meaning of morally justified or legal entitlement. Even in modern times, the word left is associated with diseases, like schizophrenia, dyslexia, and breast cancer.

But given the impressive left-handers in history and contemporary times, being a lefty seemed not so bad after all. These days, left-handed people are no longer seen as someone with disabilities or abnormalities.