1 00:00:01,920 --> 00:00:06,520 Speaker 1: Welcome to brain Stuff, a production of iHeart Radio. Hey 2 00:00:06,559 --> 00:00:09,719 Speaker 1: brain Stuff, I'm Lauren Bogelbaum, and today's episode is another 3 00:00:09,720 --> 00:00:13,119 Speaker 1: classic from our prior host, Christian Sagar. This is one 4 00:00:13,160 --> 00:00:17,759 Speaker 1: of our perhaps surprisingly rare episodes that's about actual brain stuff. 5 00:00:18,400 --> 00:00:22,040 Speaker 1: It's about how tickling works and why most humans can't 6 00:00:22,160 --> 00:00:31,160 Speaker 1: tickle themselves. Hey, I'm Christian Sagar, and this is brain Stuff. 7 00:00:31,400 --> 00:00:34,840 Speaker 1: Pop quiz hot shot? Have you ever tickled an ape? 8 00:00:34,880 --> 00:00:38,280 Speaker 1: Before it could work? As tickling is common between many 9 00:00:38,360 --> 00:00:41,040 Speaker 1: types of primates. What about a rat? You ever tickled 10 00:00:41,080 --> 00:00:43,680 Speaker 1: one of those? You'd know if you had, because rats 11 00:00:43,760 --> 00:00:46,400 Speaker 1: let out these little, high pitched chirps when you tickle them, 12 00:00:46,479 --> 00:00:49,920 Speaker 1: kind of like rodent laughter. Okay, so maybe some of 13 00:00:49,920 --> 00:00:52,400 Speaker 1: you beast masters out there have tickled both a rat 14 00:00:52,520 --> 00:00:56,880 Speaker 1: and an ape. But can you tickle yourself? Probably not, 15 00:00:57,120 --> 00:01:00,800 Speaker 1: because that is kind of impossible. Now, but before we continue, 16 00:01:01,040 --> 00:01:04,319 Speaker 1: let's do a quick primer on how tickling works under 17 00:01:04,360 --> 00:01:07,200 Speaker 1: your skin. There are millions of nerve endings that alert 18 00:01:07,240 --> 00:01:10,520 Speaker 1: your brain whenever you touch something. A light touch, what 19 00:01:10,640 --> 00:01:14,680 Speaker 1: we usually associate with tickling, is analyzed by two regions 20 00:01:14,720 --> 00:01:19,119 Speaker 1: of your brain, the somata sensory cortex, which processes touch, 21 00:01:19,560 --> 00:01:25,559 Speaker 1: and the anterior singulated cortex, which processes happiness. Together they 22 00:01:25,560 --> 00:01:29,280 Speaker 1: process the two types of tickle sensations we can experience. 23 00:01:29,760 --> 00:01:33,320 Speaker 1: The first is nismesis. This is the light sensation you 24 00:01:33,360 --> 00:01:36,199 Speaker 1: feel when something like a feather brushes against your skin, 25 00:01:36,600 --> 00:01:40,480 Speaker 1: maybe giving you goose bumps. The second, gargolesis, is more 26 00:01:40,520 --> 00:01:43,160 Speaker 1: like when your older brother holds you down and tickles 27 00:01:43,200 --> 00:01:45,800 Speaker 1: you until you laugh so hard you pee your pants. 28 00:01:46,319 --> 00:01:49,400 Speaker 1: This is the kind of tickling you can't replicate yourself. 29 00:01:50,200 --> 00:01:53,720 Speaker 1: Evolutionary biologists believe that the reason we laugh when we're 30 00:01:53,760 --> 00:01:57,920 Speaker 1: tickled is an innate, submissive response to a potential attacker. 31 00:01:58,280 --> 00:02:00,280 Speaker 1: It's kind of like when a dog rolls were on 32 00:02:00,320 --> 00:02:04,120 Speaker 1: its back and exposes its kill points to you. These 33 00:02:04,160 --> 00:02:08,600 Speaker 1: same biologists theorized that we developed tickling so we could 34 00:02:08,639 --> 00:02:12,520 Speaker 1: teach our children how to defend themselves from attacks. So 35 00:02:12,639 --> 00:02:15,560 Speaker 1: think about it. The areas where we're the most ticklish, 36 00:02:15,720 --> 00:02:18,960 Speaker 1: the under arms, the stomach, the neck, they're also the 37 00:02:19,000 --> 00:02:22,880 Speaker 1: most vulnerable to attack. Now, this is some black Widow 38 00:02:23,200 --> 00:02:26,399 Speaker 1: red room lethal training coming up here, So pay attention. 39 00:02:26,880 --> 00:02:29,640 Speaker 1: Your under arm is home to veins and arteries, and 40 00:02:29,680 --> 00:02:33,359 Speaker 1: because your rib cage doesn't protect it. Someone could easily 41 00:02:33,440 --> 00:02:37,800 Speaker 1: access your heart through there, especially with a long enough blade. Likewise, 42 00:02:38,040 --> 00:02:41,079 Speaker 1: your stomach doesn't have any defensive bones, and your neck 43 00:02:41,240 --> 00:02:44,120 Speaker 1: also has two important arteries, as well as your tray 44 00:02:44,200 --> 00:02:47,080 Speaker 1: chia bringing air to your lungs. Now, we're aware of 45 00:02:47,120 --> 00:02:50,079 Speaker 1: all of these points of vulnerability, but we still can't 46 00:02:50,120 --> 00:02:53,280 Speaker 1: tickle ourselves at them because our brains know that our 47 00:02:53,360 --> 00:02:57,720 Speaker 1: own hands don't pose a legitimate threat. Essentially, you can't 48 00:02:57,760 --> 00:03:01,080 Speaker 1: tickle yourself because of self awareness. Mri I studies have 49 00:03:01,160 --> 00:03:04,000 Speaker 1: shown that your cerebellum actually alerts the rest of your 50 00:03:04,040 --> 00:03:06,960 Speaker 1: brain when you're about to tickle yourself. This filters it 51 00:03:07,000 --> 00:03:12,519 Speaker 1: out as unnecessary information and mutes the sensation. So theoretically, 52 00:03:12,600 --> 00:03:16,320 Speaker 1: any situation that confuses your brain's ability to predict its 53 00:03:16,360 --> 00:03:21,200 Speaker 1: own actions should allow you to tickle yourself right well. 54 00:03:21,919 --> 00:03:26,800 Speaker 1: Sometimes schizophrenics, for example, can tickle themselves. This is probably 55 00:03:26,840 --> 00:03:31,880 Speaker 1: because their brains sometimes attribute their behavior to an alien source. 56 00:03:32,560 --> 00:03:38,840 Speaker 1: Researchers theorized that schizophrenic brains have biochemical or structural variations 57 00:03:38,880 --> 00:03:42,040 Speaker 1: that keep the cerebellum from alerting its owner when they're 58 00:03:42,080 --> 00:03:45,520 Speaker 1: about to tickle themselves. This means they can't tell the 59 00:03:45,520 --> 00:03:49,440 Speaker 1: difference between their hands, your hands, or the tentacles of 60 00:03:49,480 --> 00:03:55,040 Speaker 1: a giant splint. Today's episode was written by Christian and 61 00:03:55,040 --> 00:03:57,360 Speaker 1: produced by Tyler Klang. For more in this and lots 62 00:03:57,360 --> 00:03:59,320 Speaker 1: of other topics that will just tickle you because it 63 00:03:59,320 --> 00:04:01,840 Speaker 1: has to Fox the com brain Stuff is production of 64 00:04:01,880 --> 00:04:04,360 Speaker 1: I Heart Radio. More podcasts my heart Radio, visit the 65 00:04:04,320 --> 00:04:07,000 Speaker 1: iHeart Radio app, Apple Podcasts, or wherever you listen to 66 00:04:07,040 --> 00:04:07,840 Speaker 1: your favorite shows.