Being a lefty is pretty rare. Only around 10 percent of the population is left-handed

Hello kiddos,

This is Professor Mordy Maven, Thinker, Wonderer, and Figure-Outer of all things Science-ish. What that basically means is I try really hard to figure stuff out. I do the hard work so you don’t have to!

The strangest thing happened at lunch today. I sat down next to my good friend, Leib. When we both reached for our forks, we immediately banged elbows. Then it happened again. I noticed that this was happening because I was holding my fork in my right hand, while Leib was holding his fork in his left hand — which is very silly. Everyone knows your right hand is stronger and more accurate. Or is it? I mean it is for me, but maybe not for Leib. That’s when I realized I needed to understand:

Why do some people prefer their left hand over their right?

First thing you need to know is that being a lefty is pretty rare. Only around 10 percent of the population is left-handed. That means in every minyan there’s probably only one left-handed guy! What made him so special? Well, it turns out there’s no simple answer to that. In fact, even the smartest scientists aren’t exactly sure. It seems like it’s a result of a mix of genes, environment and just plain old chance. But before we explain all that, let’s take a look at the brain. (Not your brain, silly! You can’t actually see your brain. Just, you know, let’s learn more about brains.)

You’ve only got one brain, but it’s actually divided into two halves. This is called brain lateralization. Just like we have two arms, two legs and two nostrils, we have two parts of the brain. The two parts do different things. The left side of the brain (or the left hemisphere) controls the muscles of the right side. And the right side of the brain (right hemisphere) controls the movements of the left side. Criss-cross, applesauce!

So, a person who uses their left hand more often, like for writing, eating and brushing their teeth is actually using the right side of their brain to do it! (Sorry guys, seems like whether you’re a righty or a lefty you still have to brush your teeth.)