Eddie Wu

By definition, I mean, you will probably know a left-hander, but if you were to just bump into someone on the street and ask them which hand they write with or which hand they play sport with, they are mostly likely to say their right hand.

It's roughly 90% of the population that has this right-handedness to them.

But the reason why left-handedness exists is because by virtue of its infrequency, the fact that it's a bit out of the ordinary, it actually infers a certain advantage onto the people who have that property.

If you think about the fact that, say, for instance...

There are members of my family who are very avid sports followers.

And in sport, when you hold a racket or a bat with your left hand, or perhaps if you're a boxer, if your dominant hand of side is your left side, that makes you a little bit unusual.

So when you get on the tennis court, you're used to playing shots in a certain way to favor playing against the right-hander because most of the people you play against are right-handers.

But if you meet a left-hander...

you hit a shot to what you think is their weak side but actually it's their strong side and they can hit it back they can hit a winner very confidently very easily and suddenly you're in trouble now on the tennis court that's just a matter of winning or losing a game but earlier on in our evolutionary background that left-handedness would probably have inferred on you

an advantage of survival.

You know, when we talk about survival of the fittest out in the natural world, it is those people who are stronger, who maybe have to show their dominance and have to be able to fight off other people who want to lead the tribe or things like that.

That ability to be

something uncommon or unusual to your opponent, and in this case, being left-handed, is actually an evolutionary advantage.

But here's the thing, you might say, well, hold on a second, when something has an evolutionary advantage, it's going to become more and more common.

But let's imagine if we go forward tens and thousands or hundreds of years,

you would then have lots and lots of left-handers in the population.

That means that they become more common and their advantage disappears because you're meeting left-handers all the time and you're pretty familiar with the strengths and weaknesses that they have.

So in that way, if there were lots of left-handers in the population, they would very naturally decrease again and we would come back to what we call this equilibrium.

So that is part of why left-handedness exists.

Ultimately, the genes are still a bit of a mystery to us, but that hypothesis, that mathematical way of thinking about it is extremely powerful.