Ever Wondered how tickling works?

Every single person has been tickled and made to laugh so hard that you get tired of laughing. But what's the reaction everyone that everyone commonly show? Yes, laughing but also resisting. The universal reaction to tickling is STOP! or NOOOOO! Have you ever wondered why you're laughing even though you don't find tickling to be funny? For this, we'll have to look at an evolutionary basis because tickling wouldn't exist if it didn't have a purpose in us or any ancestral species of ours.

There's actually 2 types of tickling. The one that makes you laugh is called gargalesis and this is the kind of tickling you cant do to yourself. To initiate this kind of tickling, you might be familiar that the whole body is not ticklish, and only a few areas like the stomach, neck, armpit, feet and knees are sensitive to tickles. That right there is the first clue. These areas are vulnerable, as in these are spots that an attacker or predator can get you at. The neck, armpits, feet and thighs have major arteries running there. The stomach, well there are multiple organs there too. Curling up while getting tickled is more of a reflex, a safety mechanism. This shows that gargalesis evolved as a tool to protect us. 

The second type of tickling is knismesis, the itch or sensation you feel when there's an ant on your neck or the touch of a feather on the skin causes. This one doesn't make you laugh but instead gives a sudden shiver or maybe even goosebumps to let you know there is a threat or harmful object on you, and requires you to notice it. You might have already tried this, so yes, we can tickle ourselves this way.  

Moving on to why can't we tickle ourselves the gargalesis way? This is a very simple answer. The cerebellum part of the brain is always tracking your movements and at the same time also predicting your next move. So just like how you can't scare yourself, you can't tickle too because the brain knows you are about to tickle yourself. 

But is there a contradictory pair of reactions of resisting but also laughing portrayed when getting tickled? Well turns out that laughing sends out a social message. Assume that tickling made you cry, in that case, we would stop tickling repeatedly. But laughing is like positive reinforcement. In ancestral species, repeated execution of this only would lead to learning and it is of prime importance for their survival. Now for the resistance part of it, if tickling was all about laughing and fun part of it, and no runaway feeling, it wouldn't teach you about the exercise of protecting yourself.

So next time you tickle someone, let them know that tickling ain't so bad after all :)