Why are people ticklish? - Big Questions - (Ep. 39)

Hi, I'm Craig

And this is Mental Floss on YouTube. Today, I'm going to answer Tim B's big question

Why are people ticklish? No one knows for sure why people are ticklish, but luckily for us, there are people who study this for a living

Lucky for them, too. That sounds like a great job. So, I'm going to talk about some of their findings today to tickle your fancy

What's a fancy? Let's get started. Oh, stop it

Oh, oh, oh, stop. In 1997, the writers of a study published in the journal Cognition and Emotion hypothesized

that since people who are tickled laugh, they must already be in a happy mood

They tested their theory by dividing 72 undergraduates into two groups. One group was shown comedy in Saturday Night Live clips before being tickled

Another group was shown an unfunny video before being tickled. That was probably a Wheezy Waiter video

For their theory to be correct, subjects would have had to laugh more while being tickled after watching the comedy clips

But the groups laughed in equal amounts. That's science talk for. People laugh while being tickled no matter what mood they're

in. Meaning the laughter has nothing to do with actually being happy. Tickling was nothing more than a reflex

Another study done in 2013 at the University of Tübingen in Germany found that tickling

primarily activates two parts of the brain the rolandic operculum and the hypothalamus The rolandic operculum is also stimulated during regular laughter and emotions in general But the hypothalamus only activates during tickling not other kinds of laughter Interestingly it the same part of the brain

that deals with pain and instincts, like fight or flight. These two studies show that tickling is a

reflex, so it probably evolved over time. We can't know exactly why, but scientists have some theories

as they tend to. According to expert Dr. Glenn Weisfeld, is he German? What should my accent be

I'll just do American. The structures of the body that are most vulnerable to tickling are also the ones that are most

vulnerable to attack. We may be responsive to tickling because it gives us practice in defending ourselves. Yee-haw

The scientists behind the University of Tbingen study had a similar theory. They believed that parents began tickling their children to prepare them to defend themselves

That's why I tickle myself. Hee-hee-hee! Ha-cha! Another possibility comes from the book Laughter, a scientific investigation by neuroscientist

Robert R. Provine. He wrote that tickling originated as a form of social bonding

A parent tickles their baby, then the baby laughs in response. The tickling tends to stop when the baby starts a fuss, so the laughter ends