Why do we dream? A new theory on how it protects our brains
time.com
time.com
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 actually feels like the primary element of it; emotion is the core element of that, but a better description is "the lizard brain's interpretation" of what's happening in the dream, that feels like the central element of the dream.
The visual part is also not in full colour generally, in my case, it's like early movies during the transition from black-and-white, with slight colour tints generally towards the bluish colour regions.
I'm curious what others' dream experiences are like, and in particular whether it's the case that most people do experience them as primarily visual.
Like just yesterday I became aware that I was dreaming. In the dream I had somehow ended up in jail. The majority of the dream was me trying to escape in various ways, a bit like a reverse Ocean 11 thing.
As I was dreaming I could picture the places around me, I particularly recall the gate in the main corridor.
However even though my dreams are usually very visual in some sense, it's much closer to how I picture things in my mind when reading novels, rather than explicit images like when watching a movie.
I've always had a hard time with visualizations when reading novels. Like I'll read the page or two the author uses to describe some location, but most of the time the details don't really "sink in". Instead my mind seems to quickly grab hold of the high-level things, like it's an old apartment building, and the details are just generated based on that. Whatever detailed description the author makes usually doesn't affect the mental image I've already built.
I guess it's not that weird that the dream visuals feels more like that out of a book, both cases being generated by the imagination.
Dreams are so close to waking state, I’m always in awe when I successfully transition. Touch, taste, smell, every sense. It’s like waking reality, but with god mode.
That said, vision is really really weird. If you pull your sight into your dream body (hard to explain), then it’s just like you’d expect. It’s like it’s possible to see multiple perspectives at once, and it’s visual, but it’s all like one continuous field of view. Sometimes I don’t even really notice that I’m looking forward, backward, and from above all at once.
When I’m just playing around, I like to smash things and jump so high that I fly above the clouds, feeling the cold air above and the weightlessness at the apex. It’s no more visual primary than waking, IMHO.
It’s as “simple” as learning to remain aware and observant when falling asleep, without rousing oneself. No deity worship or chakra alignments necessary.
Meditation practice helps tremendously, but my first success, I accomplished by trial and error.
A lot of instruction on the Internet suggests focusing on something, visualizing something, counting, eating supplements, etc. I have found all of that unnecessary.
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.
What's really weird is how dream-reality always makes sense to you in context, regardless of how absurd or random it is, because your self awareness and identity are being simulated the same way, both in dreams and in reality. It's like a virtual machine inside a virtual machine.
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.
Edit: Perhaps immersive psychedelics (LSD, ketamine) are similar actually. Speculatively, one could define "real" as our ability to doubt, "fantasy" as the suspension of doubt.
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.
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...
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.
The idea also doesn't ignore REM sleep like you claim.
> This means we get to learn about our purely emotional behaviour, and perhaps spot where it is maladaptive.
How did you get this ? Its another interpretation of available data. Extreme story generation mode may not be end goal but artifact.
But I'm distinctly not "purely emotional" or animalistic in my dreams.
Mammals ? Reptiles ?
Data points are sparse i.e. the number of samples included are too few to strongly believe in correlations. Taking out extreme data points would make the correlations look independent.
The data values across 25 primate species are based on averages across previous studies and using proxies where some data was not available. I do not know how justifiable such approaches are but I am skeptical about them.
Also, the exposition suggests that this is somehow particularly necessary for visual information because we can't see while sleeping. They originally suggest that this is because it's dark at night, but later modify it to be because one's eyes are closed while sleeping. However, to my knowledge, very little hearing is done while one is sleeping, certainly not enough to protect the auditory portions of the brain from being taken over. Furthermore, if other senses like hearing or smelling are in fact unused while sleeping, it seems like there wouldn't be much need to protect certain regions of the brain from takeover, since there would be no other sense to take them over. Finally, it seems like there are multiple situations where senses are required in a periodic way, such as an animal active during dusk, where its senses transition from being more to less sight focused. Being able to cycle the role of brain regions in response to these changes would be widely beneficial, and we would expect the capacity for this to be deeply ingrained. Insofar as we need non-sight senses while we are sleeping, it seems like the circuitry to deal with cyclic use of senses would be able to protect the visual cortex from total reuse.
Stronger than all this, it seems like REM is fairly fundamental to sleep, in that understanding it ought to offer deep insight into why we sleep in the first place. The proposed explanation offers no such insight, and generally answers no other questions besides the one regarding dreams. It seems like answers to deep questions usually provide insight into questions we didn't even know we had, whereas this answer provides no such insight.
I saw an answer to the dreams question to the effect that the brain cools down while we are sleeping, and REM sleep heats up the brain to prevent it from becoming too cold. This answer potentially provides insight into why we sleep, in that it proposes the cooling of the brain to be important to sleep, rather than incidental. It also explains why interrupting REM would kill a person. It doesn't obviously preference visual portions of the brain, suggesting that visual information is the focus of the brain simply because it is what the brain focuses on while awake. It potentially explains the data of these researchers, if the brain cools down more during sleep whenever the brain is more flexible.
I am not suggesting that I think this answer is definitely true, but merely trying to demonstrate that the standard I am measuring this new theory against is not impossible to reach. I think the explanation of why we dream will look more like the brain cooling answer, rather than the brain reuse answer.
See: ‘Matthew Walker's "Why We Sleep" Is Riddled with Scientific and Factual Errors’
Sorry, but this is just unfair insinuation, based on nothing.
I’ve seen this claim many times, but I’ve not seen any studies that say “no [REM] sleep causes you to die”. The closest I can find are studies in the form “less [REM] sleep correlates with all causes of death to go up” - it’s not like you can literally kill someone just by keeping them awake for a month.
https://www.nhlbi.nih.gov/news/2020/study-links-poor-dream-s...
Without a good reference its just a repeated nonsense.
Even if this is true, there must be limits on it. What qualifies as 'interruption' ? Does REM taking 10ms counts as interrupted ? 100ms ? 1s ? 0ms (hard to believe this is actually possible). Its also known that some people require less sleep then others due to genetic factors. Perhaps 1m REM is enough for some...
Why do we have weekends?
Predatory neuron phenomena goes along with this theory.
> those who are born blind (or who become blind early in life) don’t experience visual imagery in their dreams; instead, they have other sensory experiences, such as feeling their way around a rearranged living room or hearing strange dogs barking. This is because other senses have taken over their visual cortex.
The prediction would be that moles experience sounds in sleep, or smell, or touch, whatever their primary sense is.
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.
> If dreams are visual hallucinations triggered by a lack of visual input, we might expect to find similar visual hallucinations in people who are slowly deprived of visual input while awake. In fact, this is precisely what happens in people with eye degeneration, patients confined to a tank-respirator, and prisoners in solitary confinement. In all of these cases, people see things that are not there.
On the other end, as you transition out of sleep to wakefulness, you pass through hypnopompia.
I experience the feeling of these waves also when I meditate.
Then, as I fall back asleep, I'm either wishing for/against that dream topic to continue. Most of the time not getting what I want.
The only time I seem to remember dreams is when my sleep is disturbed. Most nights I go to sleep and wake up in the morning, no (remembered)dream. If something wakes me up like indigestion or needing to pee I’ll often remember a dream.
A dream journal really does help though. The last thing most people want to do when sleepy is write though.
But if you want to remember your dreams again, this is something you can work/train with. Basically, every morning before getting up, not jump up with the alarm out of bed, but rather ly still, in the same position as before and try to remember. If you want to, have a dream diary. Doing so a few days, should bring your memory of your dreams back.
I used to do so to train my ability for active/lucid dreaming. Can be fun ...
(but now with a toddler and a baby I lack the time and focus)
Every other morning there’s nothing.
Also whatever malaria drug I took was supposed to have intense dreams as a side effect. (Don’t remember any)
Oh no, wait: we open our eyes every morning, so even if there was any effect, it would be the opposite: visual taking over everything else. Which also doesn't happen.
So take it with a grain of salt: yet another unprovable "theory" about the brain.
Also exactly the fact that it hasn't been fully proved out yet is why the nuance is missing. But now all the sudden you want them to be able to give you an explanation of the nuanced mechanism that prevents visual from taking over everything else? (Plus why on earth would it? What are you even talking about? I'm seeing all day long, but I'm also smelling hearing touching and tasting) Make up your mind!
2. The hypothesis is as unprovable as they come: not only do we not have any idea on how this process of taking over other brain areas would work, if you knew how it worked, you couldn't build brains that lack this mechanism but are identical for the rest, and set up an experiment in which half of the brains (modified and original) would dream and the rest wouldn't. Because that seems to be about the only experiment that could truly falsify this idea.
3. It doesn't explain why only the visual cortex is susceptible to this, when we know that other brain areas also can adapt. The argument "it's dark" doesn't cut the mustard, because the effect should go away as soon as we open our eyes, which is around 2/3rds of the day. BTW, babies can't see, so it's odd that so many of them manage to develop a normally functioning visual cortex.
4. Sleep inhibits the senses, so how can the areas they input to take over, and why don't their areas get taken over?
5. They don't even attempt to prove that REM sleep and REM sleep alone activates the visual cortex and only that.
> Make up your mind!
That was under the assumption that the hypothesis was true. It seems to lead to rather unintuitive predictions. And I do like a theory to not be in apparent contradiction with simple observations.
So no, I have no reason to take it seriously, and people that (think they) don't dream shouldn't worry.
I hear a lot about people struggling with sleep and so I recognize that it is probably a widespread problem, but I sleep like a rock most nights and have little to no stress about it.
Since this doesn’t happen, it’s an important datapoint towards a falsehood of the theory.
On thing is for sure, if we can say to remember of the dreaming, we indeed did wake up.
In personal experience, I noticed a direct connection between physiological discomfort while sleeping and the related dreaming. That is a discomfort, say in my body positioning would generate dreams around the effect of it, not always literal but often it would either trigger a brief awakening or a change of the positioning.
One very stark experience was related to a case when previously frozen (and likely swollen at night) toes were constantly triggering a dream of sleeping next to a campfire and leading invariably to waking up with my knees bent and feet tucked underneath me. Toes healed, the dream was gone.
Another very much reliable trigger is airsupply. Say, by odd positioning the breathing is affected, sometimes an external factor can affect the air quality. Sure enough, there will be some dream leading to waking up just to be annoyed at dry/stuffy nose or some random smoke from an open window finding its way in. That I should feel probably grateful about, as it's like an internal smoke alarm... (though no substitute for proper detectors!!)
The point is, the dreaming might still be an extension of our survival mechanism. Kind of internal dashboard to check while asleep, no matter how oddly scripted.
The most disappointing thing about a good dream though, is how quickly memories of it fade away upon wakening - it's like trying to grab tendrils of smoke rising away.
Usually at best I manage to recall one or two small snippets, or something about the general theme, but every now and then - very rarely - more vivid details stick with me for a little longer.
Solms. 2000. Dreaming and REM sleep are controlled by different brain mechanisms. BEHAVIORAL AND BRAIN SCIENCES (2000) 23, 793–1121.
https://neuro.bstu.by/ai/To-dom/My_research/Papers-2.1-done/...
»It is generally accepted that NREM mentation that is indistiguishable from REM dreaming does indeed occur. Monroe et al.’s (1965) widely cited study suggests that approximately 10–30% of NREM dreams are indistinguishable from REM dreams (Recht-schaffen 1973). Even Hobson accepts that 5–10% of NREM dream reports are “indistinguishable by any criterion from those obtained from post-REM awakenings” (Hobson 1988b, p. 143). If we adjust this conservative fig- ure to account for the fact that NREM sleep occupies ap- proximately 75% of total sleep time, this implies that roughly one quarter of all REM-like dreams occur outside of REM sleep.«
A recent reference that discusses this is:
Nicholas and Ruby. 2020. Dreams, Sleep, and Psychotropic Drugs. Front Neurol. 2020; 11: 507495.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7674595/
»Regarding the link between dreaming and neurophysiology, 60 years of debates has been necessary to get rid of the rapid eye movement (REM) sleep hypothesis of dreaming, and it is now acknowledged by a majority of dream researchers, be they neuroscientist or not, that REM sleep is neither necessary nor sufficient to get a dream report and that dream reports can be obtained at the awakening of any sleep stage (2, 7, 9–12). It is also now clear that the complexity and story-like characteristics of dream reports are related to sleep stages but also, and even more so, to circadian rhythms leading to more vivid and complex dreams in the morning than in the early night [e.g., (13–15)].«
This article sadly does not give a clue what could be her problem.
She says she feels tired because she feels she lives paralel lifes in her sleep.
But objectively she has NONE of the symptoms of bad sleep I get when I can't actually sleep.
So she maybe just feels emotionally tired for the first 5 minutes after she wakes up.
I once gave her my fitbit and checked her sleep -- she had almost no restless sleep like I do, she had a lot of REM and a lot of deep sleep, I'd love to have her sleep pattern.
Have someone monitor your sleep and wake you up when observing REM. There's a good chance you'll remember the dream you're currently in, and feel the disappointment of not knowing how it ends...
Some medications and /or weed can prevent dream recall.
Reference: Why else am I running naked in the supermarket?
This also sounds like a rationale for play. A safe practice zone... a sand box.
Better read my words one more time:
“People see dreams not every time they sleep, not every night, sometimes we can have multiple nights without dreams. By this moronic theory our “visual cortex” should be modified to “blind mode” just in the first night of sleep without dreams.”
Clearly “your reading comprehension wasn't up to par to tackle it in one pass” ;)
You're making a mistake in conflating dreams and sleep.
People see dreams not every time they sleep, not every night, sometimes we can have multiple nights without dreams. By this moronic theory our “visual cortex” should be modified to “blind mode” just in the first night of sleep without dreams.
Articles containing words “Mother Nature” are only good for religious organizations, homeopathy lovers and other imbeciles.