The Science of Dreaming
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The Science of Dreaming

Dreaming has got to be one of the weirdest things we do. I mean, I don’t want to diminish all the other strange crap our bodies are capable of, ’cause a lot of it is pretty cracked out. But dreams are a special kind of crazy. Like, no matter how many dreams you’ve had in your life, Every once in a while, you wake up like: “What the hell was that?” But, as with everything else, science is helping us understand why we dream, what our brains are up to when they’re doing it, and why dreaming may be critically important to the functioning of our waking brain. So try to stay awake for this one, ’cause it’s pretty cool. (intro) People have been trying to understand dreams since there were people, but the person we most associate with the science of dreaming is probably Sigmund Freud. In 1899 he wrote The Interpretation of Dreams, where he sugested that dreams were largely symbolic and allowed us to sort through the repressed wishes that piled up in our unconscious mind. And most of those wishes, you might have noticed, involve kind of weird sex stuff. Freud was, you know, Freud. In wasn’t until the 1950’s, when scientists first had tools that allowed them to read the electrical activity of the brain that we began to understand what a dreaming brain was really up to. Two researchers of the university of Chicago, Eugene Aserinsky and Nathaniel Kleitman, pioneered this research by hooking people up to the newly invented EEG machine, and monitoring their brain activity while they slept. What they thought they’d find was that the sleeping brain, was a resting brain. But what they discovered was exactly the opposite. They found that the brain activity actually fluctuates in a predicable pattern over a period of about 90 minutes. The cycle takes sleepers from an initial period of drifting off, gradually into a really deep sleep with slower brain activity back into almost awake. And the state of sleep where the sleepers were almost awake again was the most interesting. Brain activity in this phase was almost identical to when people were awake. But even more weird, during this stage the subjects became functionally paralyzed. The only parts of their bodies that moved were their eyes, which darted back and forth under their eyelids. So you know this part already; Aserinsky and Kleitman called this period R.E.M. sleep, after the rapid eye movement that characterized it. They also called it paradoxical sleep, because the subject seemed to be awake according to their brain activity, even though they were basically dead to the world. They probably figured that these names were better than “sexually aroused sleep”, which is another common feature of this stage. But another thing that scientists found out was that if R.E.M. sleepers were awakened, they reported having really vivid dreams that were often emotionally intense. It wasn’t the only stage of sleep in which subjects dreamed, but it was the time that they reported having the most lifelike dreams. It turns out that every 90 minutes or so, during the final stage of the sleep cycle, the brain phases into the R.E.M. sleep and our brains start creating crazy narratives that might last between 20 and 30 minutes. This is when you have those crazy, really vibrant dreams that you can almost confuse with reality. So, why so busy, sleeping brain, and what’s so important about dreaming that you have to paralyze my entire body in order to have realistic dreams? Well there are probably several answers but one of them is that during the periods of dreaming our brains are making important connections between real life experiences that will help us in our waking lives. These days researchers are finding that Freud was wrong about dreams in at least one important way. We don’t dream much about our hidden desires. We mostly dream about what we did that day. When we’re sleeping our brains are sorting through what happened while we were awake, deciding which new experiences were important enough to remember and which ones should get tossed. And searching for links between seemingly unrelated events that might help us be a more successful human tomorrow. And it’s actually really important that we do this while we are asleep. Because our conscious, waking brains are generally too controlling to allow this kind of creative problem solving. And this dream time activity helps our waking brains be better at things that require making connections and thinking outside the box. Dreams have actually been responsible for some really important inventions and discoveries in history. For instance, Dmitri Mendeleev came up with the system for his structure of the periodic table of elements in a dream, after months of gruelling, conscious thought was getting him nowhere. And research shows that our brains are much better at solving puzzles if they are allowed to take a nap in the middle of doing one. In 2004, for instance, subjects were asked to search for links between 2 sets of numbers. The subjects who napped solved the puzzle 60% of the time whereas only 25% of non-nappers were able to do it. In another study where people were asked to find connections between seemingly unrelated words, those who lapsed into R.E.M. sleep between sessions solved 40% more puzzles than those who didn’t. So dreams are all about making associations and finding patterns that our waking brains have a hard time detecting. that our waking brains have a hard time detecting. But it seems to work slightly differently in non-REM sleep than in REM sleep. During non-REM sleep you dream, but the dreams aren’t necessarily vivid. And they’re often about something that you’ve been doing or thinking about a lot. During these stages people often report dreaming about kind of boring stuff. Like if you spend a lot of time in the car during the day, that night you might dream about driving down a long street, stopping at a series of stop lights. This might seem lame, actually is pretty lame, but is kind of useful to the brain in it’s own way. It’s telling itself things that it already knows, like when you’re driving a car you’re supposed to stop at stop lights. So in non-REM sleep it’s basically reinforcing existing connections. But in REM sleep we get to test out that reinforced knowledge in a context that’s virtually indistinguishable from real life. It’s like our brain running a simulation. So say you were driving to your parents’ house in Boca Raton all day. In the non-REM sleep you spend a good 20 minutes doing boring stuff like practicing stopping at traffic lights. So during REM sleep your brain might have you trying to steer a steamroller through Manhattan from the back seat. REM dreams can be very life-like and very stressful, but that’s a part of it. A vivid REM dream is an opportunity to safely let us try something difficult. Cause our brains aren’t here to make friends. Our brains are here to win. The evolutionary purpose of dreaming, like the evolutionary purpose of virtually everything else we do is to make us more successful animals tomorrow than we were yesterday. In REM sleep, the brain is actually trying to experience the future in order to test possibilities. So maybe you’re making out with your 7th grade algebra teacher on Jay Z’s yacht while wearing a banana suit. What of it? Does it mean you subconsciously wanna make out with your 7th grade algebra teacher? Maybe, but not necessarily. Does the banana suit have something to do with penises? I don’t know! I’m not Freud! The thing is, during REM sleep you can try that experience with no consequences whatsoever. Another benefit of REM sleep is that it helps us process emotions that our dunderheaded waking brains aren’t really equipped to handle. Although the content of our dreams may be wacky, the emotions attached to them are completely real. Remember, your dreaming brain is charged with working on real-life problems. So if you feel really angry at your boyfriend in a dream, chances you’re probably pretty pissed at him or maybe someone else you’re close to in real life. The stories our dreams create are essentially attempts to give our emotions a narrative that can kind of suck the poison out of them and give them a form our brain can deal with better. In fact, there are people who can’t experience REM sleep, and they often experience other psychiatric disorders. So dreams help regulate the traffic between our experiences, our emotions and our memories so we can dial down the crazy. And hey, if the outcome makes your rational brain a little bit uncomfortable, well, that’s just how the sausage is made, folks. Since I’m on the topic of weird dreams in REM sleep, a lot of you have said that you’d like to know more about what’s called ‘lucid dreaming’. This is when you become aware of the fact that you’re dreaming and can actually direct the narrative of the dream. Since REM sleep is a simulation in the brain, lucid dreaming is basically a simulation that lets a portion of your conscious brain in on the action. Most of us can probably recall at least one lucid dream, and about 1 in 10 of us have them regularly. Some lucid dreamers can even communicate with researchers studying them through gestures, like eye movements and hand squeezes. What ultimately separates lucid dreams from regular old REM sleep may lie in the physiology of the brain. During non-REM sleep the cerebral cortex, that’s your gray matter, loses the ability to associate with other parts of the brain. This probably why those dreams are more boring and less complex, but once a dreamer reaches REM sleep, the cortex becomes active again and begins talking to other areas of the brain. Except for this one little part of the cortex called the dorsolateral prefrontal cortex that doesn’t reactivate. This is the region right about at your left temple that’s responsible for, among other things, applying memories to other situations. Like planning stuff and predicting outcomes. This helps explain why REM sleep dreams are often so weird. Your brain literally can’t tell what’s going to happen next. But during lucid dreaming the dorsolateral prefrontal cortex actually does wake up, which is probably why we regain a sense of self-awareness and can plot out stories for ourselves. Some people claim that lucid dreaming can help with reoccuring nightmares or even help cure depression and anxiety. The jury though is out on that, but dreaming itself, all kinds of dreaming, is definitely useful and even imperative to the function of the brain. So, if you’re still awake, go take a nap or something. Cause it’s good for you. Thank you for watching this episode of SciShow. I hope you learned something. If you wanna learn more you can go to and subscribe. If you have any questions or ideas or comments for us you can leave them for us on Facebook or on Twitter or, of course, in the comments below. Goodbye.

100 thoughts on “The Science of Dreaming

  1. I always had lucid dreams as long as I can remember.. I thought everyone dreamed like that I didn't know that some people couldn't control their actions in their sleep until like last year.

  2. Just so you know if you’re going to try lucid dreaming side effects often include increased sleep paralysis, so be prepared for this.

  3. For those really interested in dreaming, I'd like to share a summary of what most of my dreams are like. My dreams are normally so vivid that I can smell, taste and feel, things many people don't experience, as well as normally being so lucid that I'm able to directly manipulate nearly any detail of the dream, from the smallest details like telekinetically moving a grain of sand, flying or moving through walls, to manipulating even largest details like changing the weather, changing the time of day, moving planets and stars, even manipulating someone or something else's will, all through thought although it does usually require considerable effort to do anything really significant.

    Strangely, despite all those amazing things I can easily do, some of the simplest things are very difficult to do, sometimes even impossible, such as maintaining flying for long periods without extreme effort and I can never fly very high, like I'm wearing a faulty jet pack but if I fall and hit the ground, no matter from what height, I always get right back up completely unphased. Also defending myself with my fists is impossible, lol. Sure I can send the attackers flying into space with just a little thought and a little mental effort, or I can delete them from existence simply by thinking about it but that's kind of hard to do, I can also use weapons without a problem and can even throw full sized couches easily with one hand like it's a cardboard box (lol, that happened once since it was the closest thing between me and my adversary) but I just can't manage punching with any speed or power. It's like trying to effectively punch while being fully submerged in a corn starch and water mixture, just not gonna happen. Also I can make some things pop into existence out of nothing, yet when I've lost something or am looking for something I know the location of that I just had a short moment before, I never end up being able to find what I was looking for or make it appear out of thin air no matter how hard I try. Actually I think I did find something once, and sometimes things that I'm searching for do randomly appear but not from even an indirect result of anything I've done.

    That's all for now.
    If anyone's interested in asking questions or sharing their dream experiences, please feel free to do so.

  4. I heard that if you look at your hands more while you're awake, you'll do it more in your dreams, and seeing your hands somehow makes you realize you're dreaming. I tried it for a while and it was starting to work, like i had a dream where i looked at my hands and almost realized i was asleep, but i forgot to keep doing it after a while, so… Anyway, I'm uncertain if i want to know if I'm dreaming. What if i miss not knowing and can't undo it? I did used to have more vivid dreams. I miss that. My bad habits and i have been trying, sporadically, to decalcify my pineal gland

  5. Once, I had a dream where I woke up in my bed, and I saw that the exit in my room led to 2 turns. The left turn was to the old laboratory, the right – to the new one. I went to the right, there was a young woman who looked like my Russian teacher but much younger. She was sitting next to a computer, looking at the screens, CCTV, I guess? But one of the screens had some Youtube Minecraft video on it. A Youtuber built a house inside the tree's leaves. He placed a bed and suddenly I'm lying on it. The Youtuber disappeared, and when I looked at the right I saw GTA V Michael, standing on Mt. Chiliad, shooting at me with a laser gun! I'm shooting back at him while still in the bed. The mountain disappears, I'm lying in my bed, in my room. I get up and turn off the PC's power so the Minecraft GTA V virus couldn't damage it more. Now that I am back at two turns, I go left. That woman told me that the facehuggers or whatever that xenomorph queen child is named live there. Suddenly a documentary about them starts. The narrator talks about their life cycle (completely different from the Alien movies), and then they show me, sleeping in my room. A facehugger jumps on my face. I see my face, it has blood on it, my skin was soaking with it. The image slowly disappeares, they show me a bowl (for soup) with my blood-soaking skin on it. I wake up in a dream. I say that this Arabic night was amasing, then I wake up IRL.
    After that dream, the only dreams I remember well are dreams that I'm late for school, or that I have malware on my phone/laptop.

  6. how come sometimes i dream in short cutscenes across a period of time, and sometimes i experience entire interrupted 16+ hour days?

  7. once I had a dream that there was a clown serial killer trying to kill people, and i hid in a hotel and had potato cheese thingys that I still tasted when I woke up 😛

  8. That makes sense 😐. When I was high school I had an insolated dream. Because another student is still so hard to talk to he's excuse was he's a goof. I'm very insolated with had my cell phone taken for ever since last January when I got a new one. For missing my mom's call in class which was my last chance. Also I love winter, I hate ice and like it. 😒 Just my dream unusual, like poetic. It was quiet in a snow biome with cliffed hill with trees below the cliff. And a box building like a shoe box but people sized with light in it. Of course with Windows and doors but minimalistic. You can see through the windows from the cliff. Also at the right of the cliff was a river gulge that you can just jump in but I can't swim but I could've still jumped. A cross was grass I think, 😧 that part doesn't matter. I was on the cliff seeing a classmate but really another student was there at the table that was the only thing else there than the light. Doing different things, I wanted to go over to him since he was alone. I jumped down hoping the trees would cushion me, it was fine. When I got to the door, from middle school my other classmate walked by. I did see him of the day of, dream stopped there. So much messages there. One was that I need to just do stuff and it'll be fine what jump down the trees were. And the problem with the goof being so insolated. Are you real? Oh please remind me, why ask that? ~Nope you should know. 😠

  9. Does anyone know the source for 6:39 "People who can't experience REM sleep often experience psychiatric disorders"? It's for a school project

  10. Okay, so can anyone tell me why on earth I had a dream last week where there was a needle that I pulled out of my brain?

  11. Few times my dreams became true.
    They are some before anything​ or something rough is going to happen …! With me

  12. When we dream, why is it that we feel we have been dreaming for a long time, but when we wake up we realise that it was only for a short time? How long do dreams last?

  13. Also, there are instances that people start speaking aloud while sleeping(or dreaming). How is it possible if our bodies get paralyzed while dreaming?

  14. Only dreams I remember have absolutely nothing to do with real life or express one or both of my most pressing desires. Love and friendship, something I'm sorely deficient in. Never remembered a dream where I was just sitting around the house playing video games… I have agoraphobia so I don't go out much.

    The dreams that capture my fantasies are the ones I never want to wake up from. I'd be perfectly happy to accept dream life over real life if I could. While Freud may be hilariously wrong about his interpretations of the subconscious, I don't think he's wrong when he hypothesizes that our dreams, at least, have some kind of deeper meaning other than reviewing your daily activities… An emotional meaning, anyway. When I dream about having the perfect friendship or other such relationship, I'm not actively thinking about that at all while I'm awake. It's only after I've dreamed that I realize that fantasy is something I want so badly that I never want to wake up. But, if a dream is weird, (and to use your dream example) I doubt there's any other meaning to it besides "I wanted to kiss my teacher… Just to see what it's like, I guess". Oh, you've already mentioned the emotional meaning to the dreams. Thought you were throwing that out the window with Freud. No problem.

  15. I'm glad SciSho included lucid dreaming. I was about to be really unappeased with this video. Props. Lucid dreaming is transcendental, rather literally and also figuratively. It is profound, and it is the best part of human existence.

    Aside from profound wish fulfillment, doing things you could never hope to do IRL, like shrinking down to the quantum level, or flying through nebulae while filling outerspace with water, or seeing from 100 different visual perspectives at the same time; or, well, banging those top-dollar celebrities (although, sex is difficult, because it's too exciting, which tends to wake you up from a lucid dream), you can also learn from your dreams. Say, if you practice karate in your lucid dreams, you'll wake up with that experience gained. Which is something I feel should have been mentioned in the video.

    A surgeon lucid dreamer said that he practiced his surgeries in his dreams the night before. Imagine how useful that is. No chance of the patient dying.

    On top of this is the ability to speak directly to your unconscious mind–any dream figure or "character" in a dream.

    The movie Inception got it pretty good, actually. It's a shame more people don't realize that that is actually possible. Not just possible, but probable. Lucid dreaming is the best thing in the world. The experiences gained there are priceless and transcendental.

    Lucid dreaming should be taught as a skill to children, in public school. It should be a standard that everyone knows and lives. Not only can immense stress relief come from it, it can help you gain experience with physical activities, but safely. In addition, it is a great method of self-therapy, asking your unconscious mind deep things about yourself and your needs and desires and such, as well as healing past traumas.

  16. I seriously doubt that Zac Efron, three sousaphones and a dragon are going to make me more successful, but okay

  17. Had a dream that I was washing a salad bowl in the shower while someone screamed at me about how to make a proper salad from outside

  18. What if I never have dreams?

    BTW a friend of mine had a dream where he was in the Assassins Creed World. He thought he was doing a leap of faith, but he actually jumped off his bed and belly flopped on top of his little brother.

    Now I'm not gonna say that somebody will say my friend is me (I dunno what mangled train-wreck of logic they have) but if they do, I called it.

  19. I am reading all different comments of different dreams of people so that I too can dream the same in lucid dreaming. ANYONE HERE FOR THE SAME?

  20. Ugh! I tried to nap today but got jerked awake violently from that jerk that happens sometimes when you fall asleep. I couldn't get back to a comfortable state to nap. 😞 So annoying!

  21. I thought I was the only one that dreapt about mundane stuff. I don't really lucid dream, and i rem dream very, very rarely.

  22. used to nap at lunch all the time in high school. Still like a good hour nap right after work before hitting the books for my college courses.

  23. When you're driving a car, the breaks will never work correctly, and sometimes you will be trying to drive from the passenger seat 😨

  24. Why did my brain run the simulation of me asking my then-girlfriend to bury me alive(?), and her proceeding to start doing so?

  25. Tell me if this is weird or not:

    My girlfriend had to move away, but i still have her number. Sometimes i dream about actual things that we've done together. Is it just that i miss her?…or something else?

  26. I had a dream where I was in the U.S for some reason (I'm Canadian) & I was in some sort of weird cave & apparently at school in this cave learning Esperanto for some strange reason & in this cave (where I didn't learn ANY Esperanto! I hope it wasn't a paid class!) it was huge, & I mean really really huge, & roughly cube shaped, & it looked like a Mario 64 level like Wet Dry Land or something. There where floating concrete structures & platforms everywhere & it was also really well-lit despite there being no light source….. & then probably over 1,000,000 pigeons flew over & rained poo but I was luckily under a concrete platform then they disappeared to god knows where. That's all I remember.

  27. I don’t think turning into Rose Quartz from SU and walking around a giant orange cavern while being followed around by a really annoying ginger girl is going to help me today.

  28. Why is the first thing people do in lucid dreams is fly? I mean, I’d probably fly, but I’d also probably be having sex at the same time, or after I landed on the top of Mt. Everest. But that’s just me.

  29. Also, the brain has very advanced methods like deploying double sandboxing to process and experience things it predicts will be dangerous to itself. It prevents the brain from taking damage from the emotions and effects from experiencing the simulation since the damage stops in the outer sandbox when they unavoidably escape the inner sandbox.

  30. I like my dreams when I’m in space and I’m not me. And it’s like I’m watching a movie with many character’s stories.

  31. When I'm aware that I'm dreaming, I usually go grab myself a lot of desserts and snacks etc. because I know I won't get sick or fat from it 🙂

  32. Also my mom said when she's upset, she ends up dreaming that she's fighting with her own mom (my gran), which in real life she NEVER does, so who you're fighting with doesn't matter, it's the fact that you're upset in the first place.

  33. I had a dream about my whole class and school
    4 months ago I moved away from DC and I live in Las Vegas that is true I'm in Las vegas now and btw I'm from NY
    But anyway I had a sad dream about the whole school visiting me because I do miss them irl but soon when I randomly took a shower they was packing up to go back in DC and my friend said hurry up so we can say goodbye then soon when I went outside… I saw the van driving away the i started to cry in my dream but… They drived back and I thought they would come back to me but… They went the wrong way and soon when they past they waved goodbye…
    Ik it's not sad to you guys but to me it is because I miss them in dc
    My dream also played a song if you want to find it it's call
    I had a robot friend.. It's sad..

  34. This doesnt tally to how and what and why I dream.. I know for a fact most of what is said here is misunderstood by researchers..

  35. I dreamt one time…I was with my family going to visit other family members..but they were never home..let me skip the dream and just tell that part of the dream when LL Cool J was a 12/13 foot Giant…tha hell?

  36. So, yeah this Video is really old… But a day or two ago, I had a funny dream and wanted to share it, cuz Hank is in it.

    So, the whole team of SchiShow, organized a sort of Zoo where people could get to know exotic animals… I don't know why.
    My Husband and I were sponsors for this Event (I guess thats because I'm a Patreon). I was walking around, enjoying the Park… The only Animal I can remember is Scorpions… There were a few scorpions that were just walking around amongst the people. Treated by the Kids, like Goats in a petting zoo 🤔

    Suddenly I notice some kids actually being scared of an animal. I go, see what the ruckus is all about, and its a Scorpion thats about as Big as my Thigh… Kids squeal and run… The scorpion isnt walking all that quickly. But somehow, I see a clear difference between this particular Animal as opposed to all the others that are walking around without anyone caring… So I pack that Giant Scorpion into a Tupperware (how did I do that? Why a Tupperware… Well I know why it had an appearance in the dream… I use them everyday…

    Anyway… Scorpion in Plastic, off I go to try to find any of the SciShow Hosts who are supposed to be around and ward this Place… Can't find anyone, walk around for about 20min until I find Hanks Office in a group of Bungalows… In it, Hank sits behind a very Bossy looking Desk, my Husband in front of it and they seem to be engaged in a very serious conversation… I barge in – Woman on a Mission – and Say something, in a bit of a hysterical, annoying high pitched voice like: "It got out and was scaribg the Kids! So I had to trap it and I couldn't find anyone else…." stretching out the tupperware and kinda pouting.
    A very Robotic Motion in which the two men look at me is the reaction, and Hank, very slowly takes the Tupperware and said:
    "Yes. Thanks"

    I was watching my Husband fight against giant Scorpions in Assassins Creed Origins the night before. 😂😂😂

  37. LOL WUT, "we mostly dream of what we did that day?" uhhh most of my dreams are complete fiction (hell I'm not even me in some of them… as in I have a different name)
    …. I've written down a few of them, might compile a short book or something with all the ones I can remember….. I don't remember any of the "real life" dreams…….

  38. Had a dream where i was going to score with a hot red head chick…then my son touches my shoulder in the dream and says

    " You still love mommy right?"

    I screamed " Noooo…my boy!!! You are not supposed to see us naked"

    I woke up and he needed cereal and wanted me to put in some cartoons for him…it's not easy being a father and missed out on scoring with the red head

    priorities 😒

  39. "follow your dreams"
    dreams of falling into a vat of cream cheese while transgender people shout obscenities at fruits from a blimp

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