By: Shundah Yu (7th G) 2024

You may have wondered why (most) humans are right-handed.

87% of people are right-handed.

Take a look at this photo.

Source:  David W Frayer

These are the teeth of a guy who lived in Croatia about five hundred thousand years ago. Imagine that guy was cleaning an animal skin and holding a stone tool in his right hand. He bit down on the skin with his teeth and used his left hand to pull the skin tight. Then he starts scraping and cleaning the skin with his stone in his right hand. Every now and then, his stone tool slips out of his hand and scrapes his teeth. Since his tool slips out of his right hand and flies toward his left side, the scratches on his teeth will go from top right to bottom left.

That is exactly what happened to that Neanderthal guy, proving that early humans were also mostly right handed. One compelling theory of why humans are right handed is because of making tools. Like all vertebrates, each hand is controlled by the other side of the brain. So the right side controls the left hand and the left side controls the right hand. Each side of the brain controls different tasks. There is a very important region in the left side of the brain called BA44, related to hand movements, manipulating objects, and semantic tasks. Since BA44 controls the right hand, the making of tools millions of years ago thanks to BA44 could have led to the favoritism of the right side! Thanks for reading my short explanation.

References:

“Right handed Neandertals: Vindija and beyond”, January 2010Journal of Anthropological Sciences 88:113-27

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