There’s a particular kind of scream a person makes when someone unexpectedly gets them in the ribs, and it doesn’t matter one bit whether that person grew up in Guangzhou, Athens or Geelong. I know this now, because scientists have gone to the trouble of confirming it, and I have to say, of all the research to land on my desk this year, this is the one that’s made me laugh out loud the most while also feeling strangely moved.

A study published in Nature Human Behaviour, run by researchers Ziliang Xiong and Konstantina Kilteni, surveyed 448 adults from Chinese, Dutch and Greek backgrounds and asked them, essentially, to map their own bodies for ticklishness. Where do you laugh uncontrollably. Where do you not. The findings, when you actually sit with them, are rather lovely: across all three wildly different cultures, the same spots kept coming up – the neck, the armpits, the belly, and the soles of the feet. Whatever else divides us as a species, apparently the underarm remains sacred ground everywhere on Earth.

Ninety-eight per cent of respondents said they’d been tickled at least once in their life, which frankly makes me suspicious of the other two per cent, who I assume grew up in a household run entirely by robots. Just under 96 per cent admitted to tickling someone else, and 71 per cent rated themselves as moderately to very ticklish, which tracks with every family gathering I’ve ever attended, at least one of which has ended with someone’s uncle pinned to the couch, wheezing, begging for the violence to stop.

The bit that genuinely surprised me

Here’s what I didn’t expect going in: tickling isn’t just touch that’s gone slightly overboard. The researchers found real, measurable differences between the parts of the body we associate with tickling and the parts we associate with other sensations entirely, like pain or plain old pleasant touch. Which means somewhere in your nervous system, there’s a dedicated tickling department, separate from the ordinary touch department, quietly running its own operation your whole life without ever once being consulted about it.

There’s also a rather charming callback to Charles Darwin buried in the research. He apparently proposed, well over a century ago, that the parts of our body we touch least often in daily life tend to be the most ticklish – a kind of evolutionary early-warning system, wired to make us leap away from anything unexpected creeping across skin we don’t normally have eyes on. The new study found some genuine support for this. You don’t touch your own armpit thirty times a day. Your feet, similarly, spend most of their working life inside a shoe, blissfully unbothered. So when something does make contact there, uninvited, your body apparently responds the way it might to a spider: extreme, undignified, immediate.

It’s a nice theory. It’s also, the researchers admit, not the whole story – because plenty of ticklish spots don’t fit neatly into “rarely touched,” which means somewhere in the mix there’s still a proper mystery, involving physiology, psychology and probably a fair bit of “we’re not entirely sure yet, but we’re working on it.”

Why I think this actually matters

I’ll be honest, my first instinct with a study like this is to file it under “delightful but useless.” But the more I sat with it, the more I think there’s something genuinely worth holding onto here. So much of what divides us gets endless airtime — different food, different politics, different everything. And here’s a piece of hard science quietly confirming that a Greek grandmother, a Dutch teenager and a bloke from Guangzhou will all, without exception, dissolve into the exact same helpless laughter if you get them under the arms just right.

There’s also something rather touching, if you’ll forgive the word, in the finding that we’ve all tickled someone and been tickled ourselves, almost universally. It’s one of the few physical acts of affection that requires genuine trust to work at all — you can’t tickle a stranger on a train and expect a good outcome. It only lands, and it only delights, between people who already like each other. A parent and a child. Old friends. A couple who’ve been together fifty years and still, apparently, occasionally end up wrestling on the couch over who gets the last word.

The researchers say more work is needed — whether this holds true across other cultures, and how things like consent and intent change the experience, since being tickled by someone you love and being tickled by someone you don’t is, as anyone who’s ever been cornered by an over-enthusiastic nephew will tell you, an entirely different sensation.

In the meantime, I’m choosing to enjoy this one for exactly what it is: proof that somewhere beneath all our differences, humanity remains united by one simple, undeniable truth. Get anyone, anywhere, in the ribs at the right moment, and we all, without exception, lose it completely.