Why Are We (Mostly) Right-Handed? 🖐

Morning Righties!

So, it's about 130,000 years ago, and there’s this Neanderthal guy cleaning an animal skin to make clothes or something

He's holding it between his teeth while pulling it tight and scraping it with a tool.

But, every now and then, the tool would slip and accidentally scratch their front teeth.

Leaving a little mark.

Now, if we were to take a look at this guy's chompers, we’d see that these scratches all seem to go one direction, top down from right to left.

AKA the direction that is consistent with being right-handed.

But how do we know all this?

Well, turns out this guy was a real guy who lived in what is now Croatia.

And after he died, he left behind his teeth.

This is one of the many pieces of evidence showing that Neanderthals, just like us, were mostly right-handed.

See about 87% of modern humans are righties, meaning their right hand dominates over their left.

The last 13% is made up of a bunch of lefties.

And a few of those weirdo “ambidextrous” people…

But the thing is… this whole right-left handedness thing is not normal.

No other mammals that have babies like us prefer one side of the body over the other.

Not even our closest relatives, monkeys.

So that raises the question, how come we developed right handedness?

Well, it actually might come from these 2 traits we inherited from our ancient monkey ancestors.

Why?

Well, let's start with Bipedalism… aka walking upright.

See, quite a few other bipedal animals like kangaroos, for example, do actually have a preferred side, the left.

So maybe not walking around on all fours somehow leads to favoring one side over the other.

Not a super solid theory.

But the making tools theory has much more going for it.

See, like in all vertebrates, each hand is controlled by the other side of the brain.

The left hemisphere controls the right side, and the right hemisphere controls the left side.

The thing is, different sides of the brain are responsible for different tasks.

And it just so happens that there's this very important region in the LEFT side of the brain called BA44.

This area seems to play a crucial role in manipulating objects, including making and using tools.

So, the theory goes like this:

Since the left side of the brain controls the right hand, the development of tools millions of years ago thanks to the BA44 region on the left side of the brain could have led to the right side of the body being the favored side for humans!

Cool right?

So then why do lefties exist?

Probably just a genetic mutation.

And as for those ambidextrous people?

Only god knows.

Stay Cute,
Reece, Henry & Dylan 🌈

If you’re that sexy friend, subscribe here.