Why Do You Laugh When You’re Tickled?

Remember when you were a kid and a friend or sibling poked and wiggled their fingers into your ribs? Before you even had time to think, you were laughing. Not just smiling — real, uncontrollable laughter that came out in bursts while you twisted away, tried to block their hands, and maybe even protested that it was not funny.

Tickling sits in a strange middle ground that can feel part playful, part irritating, and sometimes even stressful. So why does something that’s not really funny make you laugh, whether you want to or not?

Mixed Emotions

Unlike the laugh that follows a joke from your favorite comedian, laughter from tickling is an involuntary reflex, which is why you may find yourself giggling even while desperately trying to make the tickling stop.

Though it’s a single organ, your brain is made up of different regions dedicated to different functions. When someone tickles you, sensory receptors in your skin send signals to your brain. 

Among the regions involved is the somatosensory cortex, which processes touch, including where and how strongly you’re being touched. Other parts of the brain associated with emotion and defensive responses (including your fight-or-flight reflexes) also become active. 

Like too many cooks in the kitchen, each relevant part of the brain is telling you how to feel at once. The result can be a peculiar combination of laughter, squirming, flinching, and trying to escape.

Laughter Is the Best… Defense?

Scientists still don’t know exactly why this particular kind of touch produces laughter, but one leading idea is that it may be tied to ancient defensive behavior. The ribs, neck, underarms, and feet — the areas most sensitive to tickling — are also some of the body’s more vulnerable regions. When someone unexpectedly touches one of these areas as part of tickling, your reaction isn’t just to laugh: You also pull away or try to protect yourself.

That combination of moves has led some researchers to suggest that ticklish laughter may have evolved as a signal of submission to an aggressor. In other words, the laughter could be “saying uncle,” communicating something like “You got me,” in order to defuse or shorten an encounter before it turns into something more dangerous. (Unlike with bears, playing dead does not work with tickle monsters.)

That could help explain the strange contradiction of tickling: You can laugh uncontrollably while simultaneously wanting it to stop and trying to escape. In this case, the laughter isn’t necessarily a sign of pleasure at all.

That said, some scientists think that tickling between parents and babies or young children can play a positive role in bonding. But if you’re trying to make a fellow adult feel good, telling a funny joke is probably the better move.