What do researchers know about left-handedness: What makes someone left-handed?

Fareeha Arshad

Photo by Kelly Sikkema on Unsplash

Handedness is one thing that is easily noticeable: that is whether you are left-handed or right-handed. If you ever pay closer attention to this, you will notice that there are far fewer left-handed people than right-handed ones. Ever wondered why? Well, here is all scientists know so far.

Though there is no solid explanation for this phenomenon, there are a few theories put forward by researchers governing the handedness of an individual. Most researchers unanimously agree that the handedness of any given person has to do with their genetic makeup and is perhaps a hereditary trait. This is possibly why the ratio of left- or right-handed people is roughly the same regardless of which part of the globe you look into.

If you ever pay closer attention to mundane day-to-day activities, you will notice a personal bias in your body towards a particular task. That is, you will feel comfortable performing a specific task with a particular organ of your body – either the left part of it or the right. For instance, when you type on a keyword, you tend to inadvertently use either your left or right-hand fingers to push the keyboard buttons of specific letters. The same happens when you climb up a flight of stairs; you are comfortable putting your left or right foot first, followed by the other.

Most often, such actions are done without a second thought and are a personal bias. Despite that, why don’t we have equal numbers of right and left-handed people? A few researchers agree that certain ancient societies could have played a prominent role in establishing which hand to use for a particular activity – and thus, such rules could have been passed down from multiple generations until to date.

Another widely accepted theory is how the left part of the brain controls the right-handedness of an individual. While among predominantly left-handed people, the right hemisphere of the brain plays a crucial role. Another concept widely accepted by the scientific world is that an inherent genetic mutation in the ancestral genes makes the human brain’s language centres change to the left part of the brain, resulting in the dominance of right-handedness among a few people.

Currently, further studies are being focused on identifying the genes that cause handedness among people. Researchers have hinted at external factors like birth position and estrogen levels that may affect people’s left and right-handedness.

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I am a scientist by profession and a historian by passion. I mostly write about history and science.

Texas State

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