Where did we come from? Why do we sleep? How do we age? In Professor Luke O'Neill's book, What Makes Us Human - A Scientist's Guide to our Amazing Human Existence, he looks at those questions and a whole lot more!

Join him on an educational journey through humankind, from the origin of life all the way to our eventual extinction. That may sound heavy but all we can do is laugh and have fun till then!!

And, speaking of laughter Chapter 7 actually looks at that human reaction and gives us some explainers as to why we do it. Professor Luke and the gang at Gill Books have kindly shared an extract below.

Read on...

What Makes Us Human?

Chapter 7: Here's A Good One: Why Do We Laugh?

Yes, it could be the sight of your teacher bending down and ripping his trousers or watching your friend getting pooped on by a seagull, but what is certain is that we humans love to laugh. In fact, we top the laughter league and are way ahead of cheeky chimps and hilarious hyenas. But why do we laugh? Why do we find some things funny and other things not so much? What happens when we get the giggles? Laughing is complicated stuff.

THE BEST MEDICINE

So, what happens to our bodies when we laugh in the first place? Well, let's look at the 'belly' laugh (also known as a real laugh). When you belly laugh, your belly starts to vibrate, the muscles in your ribcage contract, and these contractions force air out of your body which … hahaha! … makes the sound of a laugh. (By contrast, what scientists call 'social laughing’ doesn’t have the same effects on the body. Social laughing is the sort of laughing that adults do at tea parties or outside of a school when they are chatting nicely while waiting for you. Awkward!)

In one scientific study, researchers showed a group of women a very funny movie, then a totally unfunny one. The unfunny one was probably a health and safety video that they show you in school all the time, with a title like HOW TO USE A TAP PROPERLY or SWITCH A LIGHT ON SAFELY. The scientists then strapped monitors to the women’s bellies to count their belly laughs. The funny movie averaged 30 belly laughs per woman and the unfunny one averaged just 1 (which was probably because of a fart.). The clever scientists then took a blood sample from each woman and looked at their immune system. They studied each woman’s NK cells, or ‘Natural Killer’ cells, which don’t actually kill people, but they do kill and fight off viruses. Yes, your body is full of natural killers … cool or what? The scientists found that after laughing so much, the women’s NK activity was greater. In other words, laughing can boost our immune systems. You can hear infections everywhere scream, ‘Stop, you’re killing me!’

What Makes Us Human - A Scientist's Guide to our Amazing Human Existence is written by Professor Luke O'Neill and illustrated by Tara O'Brien. It is published by Gill Books and is available in all books shops now!