We have all had that moment when someone we know goes up to you and runs their fingers over your sides or tickles your armpits. We always try to squirm away and we tense up, but the weird thing is that we start to laugh. Nothing is funny about someone touching you in sensitive areas, so what makes us laugh while we are tickled?
First, let me explain what happens when someone tickles you. There are millions of nerve endings underneath your skin that tells your brain everything that you can feel with every part of your body as well as when you’re feeling hot or cold. When they are stimulated, two parts of the brain try to analyze it – the somatosensory cortex, which analyzes touch, and the anterior cingulated cortex, which governs emotions and rewards/punishments. When touched lightly in certain areas, you get a sensation of tickling, which makes you feel giddy but also makes you tense up and try to stop the odd sensation. Why can’t you tickle yourself? Well it turns out that the cerebellum, responsible for governing movement, alerts the rest of the brain that a tickle is about to happen, so the sensation is muted before it even starts. The brain is very efficient, so a self-tickle is considered irrelevant and not worth your mind’s attention. Why can other people tickle us then if we know it’s coming?
Many evolutionary biologists and neuroscientists believe that tickling is a form social interaction between a submissive person and an aggressor. The aggressor is teaching the other person how to defend himself from attack. It makes sense how we are most ticklish in the areas that are the most vulnerable to attack (that would cause us harm), and our response to a tickle is to squeeze our arms tighter in defense and try our hardest to stop the tickling. A common tickling spot, the underarm contains the axillary vein and artery and allows unimpeded access to your heart since it’s above the ribcage. The neck also houses the carotids, which supply blood to the brain, and the trachea, which brings air into the lungs. With no protective bones, the neck is extremely vulnerable. Some say we laugh as a form of socializing and connecting with other people, yet scientists and researchers are still not completely sure why we laugh when we are tickled. I hope you learned something new today about a very odd sensation we have.