WEBVTT - BrainStuff Classics: Why Can't You Tickle Yourself?

0:00:01.920 --> 0:00:06.520
<v Speaker 1>Welcome to brain Stuff, a production of iHeart Radio. Hey

0:00:06.559 --> 0:00:09.719
<v Speaker 1>brain Stuff, I'm Lauren Bogelbaum, and today's episode is another

0:00:09.720 --> 0:00:13.119
<v Speaker 1>classic from our prior host, Christian Sagar. This is one

0:00:13.160 --> 0:00:17.759
<v Speaker 1>of our perhaps surprisingly rare episodes that's about actual brain stuff.

0:00:18.400 --> 0:00:22.040
<v Speaker 1>It's about how tickling works and why most humans can't

0:00:22.160 --> 0:00:31.160
<v Speaker 1>tickle themselves. Hey, I'm Christian Sagar, and this is brain Stuff.

0:00:31.400 --> 0:00:34.840
<v Speaker 1>Pop quiz hot shot? Have you ever tickled an ape?

0:00:34.880 --> 0:00:38.280
<v Speaker 1>Before it could work? As tickling is common between many

0:00:38.360 --> 0:00:41.040
<v Speaker 1>types of primates. What about a rat? You ever tickled

0:00:41.080 --> 0:00:43.680
<v Speaker 1>one of those? You'd know if you had, because rats

0:00:43.760 --> 0:00:46.400
<v Speaker 1>let out these little, high pitched chirps when you tickle them,

0:00:46.479 --> 0:00:49.920
<v Speaker 1>kind of like rodent laughter. Okay, so maybe some of

0:00:49.920 --> 0:00:52.400
<v Speaker 1>you beast masters out there have tickled both a rat

0:00:52.520 --> 0:00:56.880
<v Speaker 1>and an ape. But can you tickle yourself? Probably not,

0:00:57.120 --> 0:01:00.800
<v Speaker 1>because that is kind of impossible. Now, but before we continue,

0:01:01.040 --> 0:01:04.319
<v Speaker 1>let's do a quick primer on how tickling works under

0:01:04.360 --> 0:01:07.200
<v Speaker 1>your skin. There are millions of nerve endings that alert

0:01:07.240 --> 0:01:10.520
<v Speaker 1>your brain whenever you touch something. A light touch, what

0:01:10.640 --> 0:01:14.680
<v Speaker 1>we usually associate with tickling, is analyzed by two regions

0:01:14.720 --> 0:01:19.119
<v Speaker 1>of your brain, the somata sensory cortex, which processes touch,

0:01:19.560 --> 0:01:25.559
<v Speaker 1>and the anterior singulated cortex, which processes happiness. Together they

0:01:25.560 --> 0:01:29.280
<v Speaker 1>process the two types of tickle sensations we can experience.

0:01:29.760 --> 0:01:33.320
<v Speaker 1>The first is nismesis. This is the light sensation you

0:01:33.360 --> 0:01:36.199
<v Speaker 1>feel when something like a feather brushes against your skin,

0:01:36.600 --> 0:01:40.480
<v Speaker 1>maybe giving you goose bumps. The second, gargolesis, is more

0:01:40.520 --> 0:01:43.160
<v Speaker 1>like when your older brother holds you down and tickles

0:01:43.200 --> 0:01:45.800
<v Speaker 1>you until you laugh so hard you pee your pants.

0:01:46.319 --> 0:01:49.400
<v Speaker 1>This is the kind of tickling you can't replicate yourself.

0:01:50.200 --> 0:01:53.720
<v Speaker 1>Evolutionary biologists believe that the reason we laugh when we're

0:01:53.760 --> 0:01:57.920
<v Speaker 1>tickled is an innate, submissive response to a potential attacker.

0:01:58.280 --> 0:02:00.280
<v Speaker 1>It's kind of like when a dog rolls were on

0:02:00.320 --> 0:02:04.120
<v Speaker 1>its back and exposes its kill points to you. These

0:02:04.160 --> 0:02:08.600
<v Speaker 1>same biologists theorized that we developed tickling so we could

0:02:08.639 --> 0:02:12.520
<v Speaker 1>teach our children how to defend themselves from attacks. So

0:02:12.639 --> 0:02:15.560
<v Speaker 1>think about it. The areas where we're the most ticklish,

0:02:15.720 --> 0:02:18.960
<v Speaker 1>the under arms, the stomach, the neck, they're also the

0:02:19.000 --> 0:02:22.880
<v Speaker 1>most vulnerable to attack. Now, this is some black Widow

0:02:23.200 --> 0:02:26.399
<v Speaker 1>red room lethal training coming up here, So pay attention.

0:02:26.880 --> 0:02:29.640
<v Speaker 1>Your under arm is home to veins and arteries, and

0:02:29.680 --> 0:02:33.359
<v Speaker 1>because your rib cage doesn't protect it. Someone could easily

0:02:33.440 --> 0:02:37.800
<v Speaker 1>access your heart through there, especially with a long enough blade. Likewise,

0:02:38.040 --> 0:02:41.079
<v Speaker 1>your stomach doesn't have any defensive bones, and your neck

0:02:41.240 --> 0:02:44.120
<v Speaker 1>also has two important arteries, as well as your tray

0:02:44.200 --> 0:02:47.080
<v Speaker 1>chia bringing air to your lungs. Now, we're aware of

0:02:47.120 --> 0:02:50.079
<v Speaker 1>all of these points of vulnerability, but we still can't

0:02:50.120 --> 0:02:53.280
<v Speaker 1>tickle ourselves at them because our brains know that our

0:02:53.360 --> 0:02:57.720
<v Speaker 1>own hands don't pose a legitimate threat. Essentially, you can't

0:02:57.760 --> 0:03:01.080
<v Speaker 1>tickle yourself because of self awareness. Mri I studies have

0:03:01.160 --> 0:03:04.000
<v Speaker 1>shown that your cerebellum actually alerts the rest of your

0:03:04.040 --> 0:03:06.960
<v Speaker 1>brain when you're about to tickle yourself. This filters it

0:03:07.000 --> 0:03:12.519
<v Speaker 1>out as unnecessary information and mutes the sensation. So theoretically,

0:03:12.600 --> 0:03:16.320
<v Speaker 1>any situation that confuses your brain's ability to predict its

0:03:16.360 --> 0:03:21.200
<v Speaker 1>own actions should allow you to tickle yourself right well.

0:03:21.919 --> 0:03:26.800
<v Speaker 1>Sometimes schizophrenics, for example, can tickle themselves. This is probably

0:03:26.840 --> 0:03:31.880
<v Speaker 1>because their brains sometimes attribute their behavior to an alien source.

0:03:32.560 --> 0:03:38.840
<v Speaker 1>Researchers theorized that schizophrenic brains have biochemical or structural variations

0:03:38.880 --> 0:03:42.040
<v Speaker 1>that keep the cerebellum from alerting its owner when they're

0:03:42.080 --> 0:03:45.520
<v Speaker 1>about to tickle themselves. This means they can't tell the

0:03:45.520 --> 0:03:49.440
<v Speaker 1>difference between their hands, your hands, or the tentacles of

0:03:49.480 --> 0:03:55.040
<v Speaker 1>a giant splint. Today's episode was written by Christian and

0:03:55.040 --> 0:03:57.360
<v Speaker 1>produced by Tyler Klang. For more in this and lots

0:03:57.360 --> 0:03:59.320
<v Speaker 1>of other topics that will just tickle you because it

0:03:59.320 --> 0:04:01.840
<v Speaker 1>has to Fox the com brain Stuff is production of

0:04:01.880 --> 0:04:04.360
<v Speaker 1>I Heart Radio. More podcasts my heart Radio, visit the

0:04:04.320 --> 0:04:07.000
<v Speaker 1>iHeart Radio app, Apple Podcasts, or wherever you listen to

0:04:07.040 --> 0:04:07.840
<v Speaker 1>your favorite shows.