00:00Why do people who experience sleep paralysis always see the same three things?
00:03A figure standing at the foot of the bed
00:04A crushing weight on your chest
00:06And that terrifying feeling of being wide awake, but unable to move a single finger
00:10This is what medicine calls sleep paralysis
00:12In Chinese, it's literally called, ghost pressing on the bed
00:15About 1 in 10 people has experienced it
00:17And here's the strange part
00:18No matter the country, no matter the era, people describe the same three things over and over
00:22To understand why, we first need to understand what's happening to your body during those few minutes
00:26When you fall asleep, you enter a stage called REM sleep, rapid eye movement
00:30Your eyes dart back and forth behind your eyelids
00:33Your brain activity is nearly as high as when you're awake
00:35And most dreaming happens here
00:36But during this stage, the skeletal muscles all over your body are forcibly switched off
00:41Apart from your
00:42Breathing muscles and your eye muscles, every other muscle is in a state of extremely low tension
00:46This isn't a malfunction
00:47It's protection
00:48Think about it
00:49In a vivid dream, you might be running, fighting, jumping off a building
00:52If that switch didn't exist, your body would actually act out those movements
00:56This isn't speculation
00:58There's a real medical condition called REM sleep behavior disorder
01:00In those patients, this lock is broken
01:03They swing their arms in a dream, and their arms really do swing
01:05They dream of running away, and they really do bolt out of bed
01:08Some have injured the partners who slept beside them for decades
01:11Some have climbed out of windows in the middle of the night
01:13So every night, your brain locks your body down first, and only then lets you dream
01:17Sleep paralysis is when that lock fails to release properly
01:20Your consciousness wakes up first
01:22Your body is still locked
01:23Your eyes can see
01:24Your ears can hear
01:26The room is the real room
01:27But your motor system is still stuck in the dream
01:29You think you're struggling desperately
01:31But you can't move a single finger
01:33That part is the body
01:35Now let's talk about the three things
01:36Harvard Medical School reviewed the literature on sleep paralysis and categorized the hallucinations people experience in those minutes into three
01:41types
01:42The first is the intruder type
01:44Doorknobs turning
01:45Footsteps on the floor
01:46A human silhouette standing in the room
01:48You feel, with total certainty, that there's another presence in the room
01:51And it's hostile to you
01:53The second is the incubus type
01:54Your chest is crushed by an impossible weight
01:56You can't breathe
01:58Someone is choking you
01:59Someone is sitting on top of you
02:01In Chinese, that character for, press, comes right from this
02:04The third is the vestibular motor type
02:06You float upward
02:07You leave your body
02:08You watch yourself lying on the bed from above
02:10Or you feel yourself spinning, falling
02:12Many so-called
02:14Out-of-body experiences fall into this category
02:16Just these three
02:17Whether you're Chinese, Japanese, Egyptian, or Italian
02:20Whether it's 1920 or 2026
02:23Whether you believe in the supernatural or in nothing at all
02:25People describe the same three categories, again and again
02:28This isn't culture
02:30This is neurology
02:31So why these three, and not something else?
02:33The leading explanation today is called the threat-activated vigilance system
02:36The human brain has a very ancient mechanism whose job is to raise the alarm before you're
02:40even consciously aware of a threat
02:41In the sleep paralysis state, this system gets activated
02:44But the room is completely empty
02:46So the brain hits a dead end
02:47The alarm is ringing, but there's no source to point to
02:49And the brain cannot tolerate a signal with no explanation
02:52It has to attach that fear to something
02:54So it starts manufacturing
02:56It builds a shadow standing in the room
02:58It builds a weight pressing on your chest
03:00It builds the sensation of your
03:02Body leaving itself
03:03You think you saw something
03:05In reality, your brain invented a cause for an alarm that had no source
03:08There's one more layer
03:09Studies find that the strength of a person's belief in the supernatural correlates with which
03:12type of hallucination they report
03:13The more someone believes in ghosts, the more likely they are to report the intruder type
03:17and the vestibular motor type
03:18In other words, your brain supplies the feeling that someone is there
03:21And what you believe decides who that someone is
03:23The same neural activity, in one person, looks like a demon
03:26In another, an alien
03:28In another, just a shapeless shadow
03:30I have to be honest here
03:32Science hasn't fully figured out the mechanism behind sleep paralysis
03:35Even a scholar who built his whole career on this direction, Jay, Alan Shane, has admitted
03:38he's still in the dark about the underlying mechanism
03:40I'm giving you the explanation with the strongest evidence, not the final answer
03:43So when
03:44Are you most likely to run into it?
03:46Severe sleep deprivation
03:47Days of staying up late
03:49Jet lag
03:50Stress
03:51People with high anxiety levels experience it more often
03:54Sleeping on your back is also associated with it
03:56And it feeds on itself
03:58People who've been paralyzed once start fearing it happening again
04:00And that fear itself pushes the probability up a little more
04:03If it does happen, don't fight your body
04:05Start with what recovers easiest
04:07Move your eyeballs first
04:08Then blink
04:09Then move the muscles around your mouth and your tongue
04:12Once the tension comes back, then move your neck and fingers
04:15It can't hurt you
04:16In a few seconds to a few minutes, it ends on its own
04:19Experiencing it once or twice is completely normal
04:21It doesn't mean anything
04:22But if it happens often, so often that it disrupts your life, go see a sleep specialist
04:27So, in the end
04:28Those three things were built by your brain
04:30But what they look
04:31Like, that's up to you, and your culture
04:33Your culture doesn't create the fear
04:35It just gives that fear a face
04:37The next time it comes, you'll probably still be afraid
04:40Because knowing it's neurology, not a ghost, and lying there unable to move while something
04:43stands at your bedside, those are two completely different things
04:45Your rational mind is awake
04:47But your fear hasn't woken up yet
04:49So tell me
04:50That thing you saw, was it the kind you'd heard about since you were a child?
