Welcome to brain Stuff, a production of iHeart Radio. Hey brain Stuff, I'm Lauren Bogelbaum, and today's episode is another classic from our prior host, Christian Sagar. This is one of our perhaps surprisingly rare episodes that's about actual brain stuff. It's about how tickling works and why most humans can't tickle themselves. Hey, I'm Christian Sagar, and this is brain Stuff. Pop quiz hot shot? Have you ever tickled an ape? Before it could work? As tickling is common between many
types of primates. What about a rat? You ever tickled one of those? You'd know if you had, because rats let out these little, high pitched chirps when you tickle them, kind of like rodent laughter. Okay, so maybe some of you beast masters out there have tickled both a rat and an ape. But can you tickle yourself? Probably not, because that is kind of impossible. Now, but before we continue, let's do a quick primer on how tickling works under
your skin. There are millions of nerve endings that alert your brain whenever you touch something. A light touch, what we usually associate with tickling, is analyzed by two regions of your brain, the somata sensory cortex, which processes touch, and the anterior singulated cortex, which processes happiness. Together they process the two types of tickle sensations we can experience.
The first is nismesis. This is the light sensation you feel when something like a feather brushes against your skin, maybe giving you goose bumps. The second, gargolesis, is more like when your older brother holds you down and tickles you until you laugh so hard you pee your pants. This is the kind of tickling you can't replicate yourself. Evolutionary biologists believe that the reason we laugh when we're tickled is an innate, submissive response to a potential attacker.
It's kind of like when a dog rolls were on its back and exposes its kill points to you. These same biologists theorized that we developed tickling so we could teach our children how to defend themselves from attacks. So think about it. The areas where we're the most ticklish, the under arms, the stomach, the neck, they're also the most vulnerable to attack. Now, this is some black Widow red room lethal training coming up here, So pay attention. Your under arm is home to veins and arteries, and
because your rib cage doesn't protect it. Someone could easily access your heart through there, especially with a long enough blade. Likewise, your stomach doesn't have any defensive bones, and your neck also has two important arteries, as well as your tray chia bringing air to your lungs. Now, we're aware of all of these points of vulnerability, but we still can't tickle ourselves at them because our brains know that our own hands don't pose a legitimate threat. Essentially, you can't
tickle yourself because of self awareness. Mri I studies have shown that your cerebellum actually alerts the rest of your brain when you're about to tickle yourself. This filters it out as unnecessary information and mutes the sensation. So theoretically, any situation that confuses your brain's ability to predict its own actions should allow you to tickle yourself right well.
Sometimes schizophrenics, for example, can tickle themselves. This is probably because their brains sometimes attribute their behavior to an alien source. Researchers theorized that schizophrenic brains have biochemical or structural variations that keep the cerebellum from alerting its owner when they're about to tickle themselves. This means they can't tell the difference between their hands, your hands, or the tentacles of a giant splint. Today's episode was written by Christian and
produced by Tyler Klang. For more in this and lots of other topics that will just tickle you because it has to Fox the com brain Stuff is production of I Heart Radio. More podcasts my heart Radio, visit the iHeart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.