Why the Heck Are We Ticklish?
Hey smart people Joe here.
Ya know, we've explained a lot of weird bodily functions on this show but there's
one that we haven't covered that's always confused me: Tickling.
It's one of the great contradictions of the universe, like jumbo shrimp, or saying
“that's your only choice”. (that doesn't make sense) Because tickling makes us laugh.
But we hate it.
Basically no one likes being tickled.
Go tickle someone right now.
Actually…
I'm shooting this during COVID-19, physical distancing, all that… so maybe don't do
that unless it's someone in your house you're hunkered down with or this has all cleared
up by the time you're watching this.
Also ask them permission first, otherwise that's just really rude (or maybe assault)
but what happens?
They might laugh, but the universal reaction to being tickled is pretty much, “please
stop, no thank you, SERIOUSLY STOP OR I AM GOING TO BLEEP]”
What are you for, tickling?
What's the point of you?
Why do you exist?]
We're gonna dig down in the soft tummy tum of science and see if we can shake out some
answers to why we're ticklish, what is it really for, and what is it that makes tickling
the unfunniest thing that makes us laugh.
[OPEN]
So, I know what you're wondering: can you tickle yourself?
The answer?
It depends!
Because There's actually two different kinds of tickling.
The kind of tickling we're most familiar with is called gargalesis.
That's the one that makes us freak out and laugh and it's the one you can't do to
yourself (that'll be important later).
Now almost everyone has been tickled before.
We do it to make kids and babies laugh, maybe you do it
when you're feeling a little flirtsy with someone you like.
But it's a real head-scratcher.
Or armpit scratcher.
Not a good image.
People have been confused by tickling for thousands of years.
Aristotle attributed our ticklishness to the softness of our skin, and us being “the
only creatures” smart enough to find things funny.
Even my boy Darwin wrote about tickling.
He didn't exactly hit the nail on the head – he thought that to be ticklish, you had
to be in a good mood, which isn't true – but he did give us that one question we always
have to ask for weird behaviors like this: What's the evolutionary purpose?
I mean, tickling wouldn't exist if it didn't have a biological purpose for us *or* to one
of our species' ancestors.
And we're gonna figure that out.
Clue #1?
This.
Only some areas of our bodies are sensitive to gargalesis.
I mean, try to tickle someone's shin, and you won't get much of a reaction.
Get them here, though and …
Turns out other primates tickle each other too, when they're doing a kind of rough
and tumble play.
This may hold some hints to why it exists.
Our “ticklish spots” are really vulnerable areas of our body.
And I don't mean “emotionally vulnerable” I mean in the “this is where a predator
or an attacker would try to get you so they could kill you” You've got major arteries
here, and here, and major organs and other necessary-for-living parts, here, here, and
here.
So you recoil, you curl up in a ball, it's a reflex.
Gargalesis probably evolved as a way to help us protect ourselves.
Those ticklish spots don't really apply to the other kind of tickling, Knismesis.
That's the tickle you feel when something moves lightly across your skin.
You can feel this almost anywhere on your body, and it can lead to anything from goosebumps
to those whole body shudder.
Now, knismesis isn't typically associated with laughter, but some people do like it.
And it's kind of easy to see where it may have come from.
This kind of tickle is like an alarm going off on your skin, you know, in case there's
like a dozen spiders crawling up your neck or something, you're gonna want to notice
that.
Definitely not funny.
And that's why it leads to involuntary twitching and shuddering and scratching to get potentially-dangerous
creepy crawlies off our skin.
(Next time someone scratches your back, bet you look at it differently).
It's just a physical touch reflex - and you can do this kind of tickling to yourself.
But this kind of tickling isn't really associated with laughter…
…while gargalesis is. But why?!
Why does tickling make us laugh?
I mean, why doesn't it hurt?
Or burn?
Or just tingle?
Why the heck is trying to protect your internal organs from would-be attackers FUNNY?!
That brings us to clue #2: You can't tickle yourself.
No matter how hard I try, I can't tickle myself with gargalesis.
Why?
For the same reason you can't scare or startle yourself.
You've got a part of your brain that always knows your next move.
It's why I can pick something up without looking.
My brain is predicting my movements, it's looking for feedback, making little adjustments.
The point is my brain knows what I am trying to do, and if I try to tickle myself, my brain
overrides the whole tickling program.
So for gargalesis, the laughy tickles, only other people can tickle us.
That tells us tickling is social.
The same way that talking or facial expressions send messages to each other, tickling is sending
a social message too.
So what's the message?
Scientists have done some pretty weird experiments to figure this out.
It turns out the person tickling us doesn't have to laugh for us to laugh.
Even when someone wearing a mask tickles a baby, the baby laughs.
Kind of a creepy experiment.
Don't do that.
And it turns out adults laugh even when they think a machine is tickling them.
Which is also a weird experiment.
Now we've got two clues to help us figure out tickling: #1 Our ticklish spots are vulnerable
places we need to protect.
And clue #2 You can't tickle yourself.
So maybe the reason we laugh is to get other people to tickle us.
Yeah, even though we hate it.
Just hear me out..
If you tickled someone, and they started crying, you'd stop.
So laughter is positive reinforcement, it's a social message that makes the people tickling
us happy, to encourage them to keep doing it.
Why should they keep doing it?
Because rough-and-tumble play in animals is an important part of learning and developing
and growing up, and to our ancestors, it would have been important for survival.
It's how we'd practice skills like fighting, hunting, and protecting ourselves.
On the flip side, if tickling was only about laughter and pleasure - if it didn't give
you that “run away” feeling, you wouldn't recoil or fight back.
Which doesn't teach that important evolutionary lesson about “protecting yourself”.
And it turns out other animals laugh when tickled too.
Our primate cousins make a laugh-like ha-ha sound during tickle play.
And it probably goes back farther along our family tree.
You can even tickle rats, and people have done it, for science.
When they're tickled they emit high frequency noises.
Why?
I don't know the mind of a rat, but the high frequency sounds they make when tickled
are the same ones they make when playing with other rats and when they're given food.
Tickling seems to make them happy and the laugh might encourage other rats to keep doing
it.
So, tickling is probably an ancient social behavior from way back in our evolutionary
past that helps animals learn how to protect themselves.
But more importantly, even though tickling makes us laugh, that laughter doesn't have
anything to do with things being funny.
And this is why tickling teaches us something really important about laughter itself.
We tend to think laughter is always tied to funny things, but it's not.
(it's snot… heh)
There are people who study laughter, and they are called “gelotologists”.
And one thing we know from their research is that more than anything else, we laugh
for each other.
People are more than 30 times more likely to laugh when they're with other people
than alone.
I've talked about that a little before.
And we have also learned that fewer than 1 in 5 laughs are actually in response to humor.
Seriously.
Just watch two people have a normal happy conversation sometime.
In between the talking you'll see a ton of .... We laugh when we're nervous, we
laugh just to fill space in a conversation, or just to tell the person we're talking
to that we're listening.
Most of the time, laughs are just… social noise, they're filler.
Unless you're laughing at my jokes, those are real….
And have you ever been so sad, or so mad, you laughed?
It's weird, but we know that to our brains, the experience of social discomfort – or
emotional pain – is a lot like physical pain.
We think laughing prompts our bodies to release beta-endorphins, hormones that act like our
body's own painkillers.
The point is laughter is one of our most complex social behaviors.
We use it to send lots of different messages, most of which have nothing to do with humor,
so it's not surprising that its link to tickling is… complex too.
So here's what we know: Tickling is almost built into our bodies, it's like a reflex.
The places we're ticklish are the places we are most vulnerable.
And even though we laugh, tickling isn't funny.
We tickle each other as part of a weird and complex kind of play that our evolutionary
ancestors relied on to teach each other to be safe, and laughter is the reward for our
brain that makes us want to do it to each other.
Remember, we're animals, and that's why laughing makes us feel good really deep down,
and tickling can reinforce social bonds with the people we love.
I TAKE IT BACK I DON'T LIKE SOCIAL BONDING.
