Why do we dream? A new theory on how it protects our brains • Hacker News Board

Re: Why do we dream? A new theory on how it protects our brains

#111

Post by hx2a » Fri, Jan 01, 2021, 4:40 PM UTC

sundarurfriend wrote: post #92

> dreams are primarily visual precisely because ... This is a central claim in the article that's just stated and taken for granted. In my experience, at least, dreams are not primarily visual. They have a visual component, but also a vague auditory component, a motor-experience (feeling of movement) component, etc., and all of those feel equally important. And most of all, there is a "felt experience" component that…

I've had recurring dreams that were entirely in math. And by that I don't mean a dream where I was sitting in math class or something. I mean the actual substance of the dreams were equations that I was trying to make sense of.

In my awake life I like math a lot and am comfortable solving equations. The dreams themselves, though, were terrifying in ways no other dream has ever matched.

Re: Why do we dream? A new theory on how it protects our brains

#112

Post by kenjackson » Fri, Jan 01, 2021, 4:43 PM UTC

I don’t buy the theory. If you lose your vision, like the boy in the story then I’d expect that you’d eventually stop dreaming. It doesn’t make sense that other senses would start then fighting for protection of their neural circuitry. Why didn’t they earlier then?

What feels more likely to me is that your brain is trying to optimize something in it, which is why it is correlated with plasticity. The brain has evolved to turn off most of the body (since there’s probably strong selection against moving limbs while sleeping), but little selection against moving eyes while closed. REM is just what is left of our bodies movements.

Re: Why do we dream? A new theory on how it protects our brains

#113

Post by adamjb » Fri, Jan 01, 2021, 4:46 PM UTC

alexpetralia wrote: post #105

agumonkey wrote: post #96

Earlier quoted context omitted.

To me the most peculiar aspect of dreams is how vivid the universe you're in is. It feels as emotionally impactful as the best moments of your life. Super weird

I've thought of dreams as unique in suspending self-doubt. For some reason, while in a dream, we are incapable of doubting what is going on. Everything feels incredibly vivid and real. Then we wake up, and we go back to doubting: "Ah, must've been a dream!" Edit: Perhaps immersive psychedelics (LSD, ketamine) are similar actually. Speculatively, one could define "real" as our ability to doubt, "fantasy" as the suspen…

Dreams made a whole lot more sense to me when I learnt about idea of the brain as a predictive processing machine. It asserts that the brain works as a sort of recursive two-sided process, with theory creation on one side and evidence collecting on the other. Recursive in that the visual processing system might get a "is that a door?" theory from a higher level system, which it'll then answer by collecting and trying to match evidence from multiple lower level systems ("is that an edge?" "is that a shadow?" etc.) until it eventually reaches the level of processing stimuli directly, with each system on the way acting as both questioner and answerer.

In this framework dreaming is when the evidence collecting side becomes a lot less rigorous than it usually is, so it says "sure, why not" without reference to a stimulus (i.e. a way to be falsified). In other words it's the brain's predictions continuously coming true.

Re: Why do we dream? A new theory on how it protects our brains

#114

Post by dqv » Fri, Jan 01, 2021, 4:53 PM UTC

sundarurfriend wrote: post #92

> dreams are primarily visual precisely because ... This is a central claim in the article that's just stated and taken for granted. In my experience, at least, dreams are not primarily visual. They have a visual component, but also a vague auditory component, a motor-experience (feeling of movement) component, etc., and all of those feel equally important. And most of all, there is a "felt experience" component that…

I experience the same color dullness, although warm colors like red are more vivid for me.

Something I've noticed that I've never heard anyone else talk about is text-based dreams. That is, the dream primarily happens in a text interaction where the visual space is completely engulfed by a chatroom-like interface. The visual element is not the primary aspect of the dream, instead the text in the dream is projected into the visual space. Obviously this is because I spend a lot of time in chatrooms.

Re: Why do we dream? A new theory on how it protects our brains

#115

Post by rtx » Fri, Jan 01, 2021, 4:56 PM UTC

alexpetralia wrote: post #105

agumonkey wrote: post #96

Earlier quoted context omitted.

To me the most peculiar aspect of dreams is how vivid the universe you're in is. It feels as emotionally impactful as the best moments of your life. Super weird

I've thought of dreams as unique in suspending self-doubt. For some reason, while in a dream, we are incapable of doubting what is going on. Everything feels incredibly vivid and real. Then we wake up, and we go back to doubting: "Ah, must've been a dream!" Edit: Perhaps immersive psychedelics (LSD, ketamine) are similar actually. Speculatively, one could define "real" as our ability to doubt, "fantasy" as the suspen…

One theory I had read a longtime ago was that nightmares were a way for the subconscious mind to wake-up the conscious mind.

Re: Why do we dream? A new theory on how it protects our brains

#116

Post by bonoboTP » Fri, Jan 01, 2021, 4:59 PM UTC

lisper wrote: post #109

agumonkey wrote: post #96

Earlier quoted context omitted.

To me the most peculiar aspect of dreams is how vivid the universe you're in is. It feels as emotionally impactful as the best moments of your life. Super weird

I occasionally have lucid dreams, where I realize I'm dreaming. When that happens, I can take control of the dream and do cool things like fly. Usually this only lasts a minute or two and then I wake up. But on a handful of occasions I've reverted to a non-lucid state, where I forget that I just figured out that I'm in a dream, and I lose control again. It's super freaky, and raises some pretty deep existential quest…

In another kind of "weakly lucid" dream type I know I'm dreaming but I don't have (full) control. So I can't make people answer what I want, but it feels like I can "mentally manipulate" them and push their answer to a certain direction, like make an attacker friendlier or so.

Re: Why do we dream? A new theory on how it protects our brains

#117

Post by bonoboTP » Fri, Jan 01, 2021, 5:04 PM UTC

FailMore wrote: post #79

This idea ignores a fascinating aspect of REM sleep. During REM, the brain shuts down the executive functions, while the brain goes into extreme 'story generation mode'. A story in which you are a character. I think this is one of the most overlooked and interesting parts of dreaming. We are able to observe ourselves in our dreams acting without the constraints of our 'executive functioning' brain. This means we get…

I definitely feel like I have "executive function" even in many non-lucid dreams. It's just that I assume it's reality but I'm still solving problems, fighting, running away, talking to people to achieve things. Yes the world changes in weird ways and the distinctive thing about dreams is not noticing that this level of weirdness is implausible.

But I'm distinctly not "purely emotional" or animalistic in my dreams.

Re: Why do we dream? A new theory on how it protects our brains

#118

Post by opan » Fri, Jan 01, 2021, 5:28 PM UTC

dqv wrote: post #114

sundarurfriend wrote: post #92

> dreams are primarily visual precisely because ... This is a central claim in the article that's just stated and taken for granted. In my experience, at least, dreams are not primarily visual. They have a visual component, but also a vague auditory component, a motor-experience (feeling of movement) component, etc., and all of those feel equally important. And most of all, there is a "felt experience" component that…

I experience the same color dullness, although warm colors like red are more vivid for me. Something I've noticed that I've never heard anyone else talk about is text-based dreams . That is, the dream primarily happens in a text interaction where the visual space is completely engulfed by a chatroom-like interface. The visual element is not the primary aspect of the dream, instead the text in the dream is projected i…

I've had many dreams featuring IRC or the chat of an old MMO. I also heard it's very uncommon to see text in dreams, though.

Re: Why do we dream? A new theory on how it protects our brains

#119

Post by sundarurfriend » Fri, Jan 01, 2021, 5:46 PM UTC

adamjb wrote: post #113

alexpetralia wrote: post #105

Earlier quoted context omitted.

I've thought of dreams as unique in suspending self-doubt. For some reason, while in a dream, we are incapable of doubting what is going on. Everything feels incredibly vivid and real. Then we wake up, and we go back to doubting: "Ah, must've been a dream!" Edit: Perhaps immersive psychedelics (LSD, ketamine) are similar actually. Speculatively, one could define "real" as our ability to doubt, "fantasy" as the suspen…

Dreams made a whole lot more sense to me when I learnt about idea of the brain as a predictive processing machine. It asserts that the brain works as a sort of recursive two-sided process, with theory creation on one side and evidence collecting on the other. Recursive in that the visual processing system might get a "is that a door?" theory from a higher level system, which it'll then answer by collecting and trying…

> brain as a predictive processing machine. It asserts that the brain works as a sort of recursive two-sided process, with theory creation on one side and evidence collecting on the other.

SlateStarCodex has a nice article[1] about this.

> The key insight: the brain is a multi-layer prediction machine. All neural processing consists of two streams: a bottom-up stream of sense data, and a top-down stream of predictions. These streams interface at each level of processing, comparing themselves to each other and adjusting themselves as necessary.

> ...

> You’re not seeing the world as it is, exactly. You’re seeing your predictions about the world, cashed out as expected sensations, then shaped/constrained by the actual sense data.

[1] https://slatestarcodex.com/2017/09/05/book-review-surfing-un...

Re: Why do we dream? A new theory on how it protects our brains

#120

Post by GordonS » Fri, Jan 01, 2021, 5:53 PM UTC

lisper wrote: post #109

agumonkey wrote: post #96

Earlier quoted context omitted.

To me the most peculiar aspect of dreams is how vivid the universe you're in is. It feels as emotionally impactful as the best moments of your life. Super weird

I occasionally have lucid dreams, where I realize I'm dreaming. When that happens, I can take control of the dream and do cool things like fly. Usually this only lasts a minute or two and then I wake up. But on a handful of occasions I've reverted to a non-lucid state, where I forget that I just figured out that I'm in a dream, and I lose control again. It's super freaky, and raises some pretty deep existential quest…

> I occasionally have lucid dreams, where I realize I'm dreaming. When that happens, I can take control of the dream and do cool things

I experience lucid dreams I can control quite frequently. The thing I do most often is let the dream play out, but go back in (dream) time to replay certain scenes differently if I'm not happy with the outcome.

It's really pretty cool - like being in some kind of super-advanced VR simulation, or under the influence of some impossible drug. If anyone ever figures out tech to make this just happen (kind of like simulation VR goggles in scifi films), they are going to be very, very rich.