That's awesome. I don't find it hard to believe that the octopus is dreaming, but I am a little skeptical of the interpretation of the evidence. Humans get erections throughout the night which have nothing to do with sexual dreams, so maybe the chromatophores cycling are just like that.
What about a purely "maintain in good functional state"? I mean, when there are not used, muscles atrophy. Maybe a similar phenomenon would happen if these cells were not regularly stimulated during sleep.
Urine attracts ticks and wet loin cloths can cause skin damage. Though for the erection part, erections are linked to the parasympathetic nerve system, which is fully active during sleep.(Which is why it's hard for men to get erections when they're chronically stressed)
Experiments with mice have shown that if you shock mice at certain times during sleep, their fear conditioning will change. https://academic.oup.com/sleep/article/26/5/527/2707886 This seems to indicate that sleep acts like an unsupervised learning reinforcer.
Sleep might be required for a certain level of consciousness.
You might be interested in "hippocampal replay" and "sequence reactivation" during sleep
TL;DR during sleep, most critters' brains actively "re-play" waking experiences, and this contributes to learning+memory. I can't find the paper right now, but at a talk in ~2013 some guy presented work in which spatial trajectories run by rats were reconstructed from hippocampal place cell activation sequences during sleep
If you spend enough time in a sensory deprivation tank, you will usually start experiencing abstract thoughts and sensory hallucinations. Dreaming is likely similar in that it's just the natural result of a few moving parts:
1. An eager sensory network with no inputs can introduce phantom inputs into the network, which can evolve through feedback loops in networks not being stimulated by real sensory phenomena
2. The brain and body's tendency to actively "simulate" its internal representation of the world, by creating mental scenarios and then playing them out.
When you throw a baseball, your CNS & muscles run simulations which adjust your motor neuron activation profile and the way your muscular cells function based on feedback from the brain about the success of the action.
When you practice a speech, you visualize the place you will be delivering it, visualize the audience and their potential reactions, so that you can plan accordingly. This is another kind of mental simulation.
Dreams might be the same thing, generating sensory feedback loops from brain activity resulting from memory organization and compression during the sleep cycle, simulating a world and then running through the simulation.
This can greatly increase an organism's survival if the organism's entire life revolves around finding food and avoiding predators / catching prey. While they are hidden and safely sleeping, animals are still able to "train" themselves completely unconsciously.
Seeing as how evolutionarily useful it is, I'm not surprised to see it crop up in multiple kinds of brains and would be very surprised if advanced aliens do not dream as well.
To me the question is if the octopus is subjectively experiencing the dream. I guess there's no reason to think it doesn't. Dogs definitely seem to dream and wake up scared shitless at times...cephalopods seem smarter than dogs.
I think it does based on my theory for the strong evolutionary benefits of dreaming. If consciousness is a result of total brain and body function, then some level of that consciousness is needed in order to carry out survival-based simulations while you sleep.
The level of consciousness can vary between organisms and dreams. As an active lucid dreamer I frequently enjoy full "consciousness" in my dreams, able to fully make decisions instead of subscribing to my brain's prestructured rules for navigating the simulated construct. I can even often control the parameters of the simulation itself.
Most people however never experience this kind of dream, and are completely slave to the dream. The only thing which imparts their subjective experience is the ability to recall the dream. Memory is definitely a key component to a subjective experience.
Being able to make decisions in a dream is normal, right? I think strategically in my dreams, mull over advantages and disadvantages and plan my response the same way I would while awake - with less clarity though. Sometimes I get so carried away that takes up the whole dream. I don't think that's atypical.
I also get pissed off when I recognize something that's logically contradictory or impossible and realize it's a dream - although I miss a lot of obvious tells.
It's actually very atypical. Most people do not lucid dream or at least recall a lucid dream more than a handful of times in their lives, and certainly not intentionally. More people can make their own decisions, to some capacity, but the insight that your situation isn't real isn't common.
> I also get pissed off when I recognize something that's logically contradictory or impossible and realize it's a dream - although I miss a lot of obvious tells.
I would use that chance. If you are aware that you are dreaming, you can change the contents of the dream. Google "lucid dream".
Depends on the dream. I've developed a sense of how much brain activity I have going on.
Sometimes I have a good grip, I'm deep in REM, and I can do anything I want for a while with no consequence. I am still tending to my brain activity but it's manageable. Other times, the slightest deviation from my preprogrammed behavior is enough to perturb the dream.
I have countless times woken up when pushing myself too far, but it's gotten better. So sometimes I am quite lucid but just have to not think too hard or deviate much from my preprogrammed behavior. Too much effort or going too wild breaks the dream. But very often I choose to fly around, visit places and people, and sometimes interact.
I've even had a few dreams where I've managed to do simple arithmetic and memory recall without waking up. Plenty of dreams where I try to write things down thinking I'll still have it when I wake up.
A recent fascination I've had the last few months is pushing boundaries with my dream characters. Several weeks ago I had a dream where I was having a conversation with someone, and paused to observe that the situation wasn't real. Normally I've found I have to keep this knowledge to myself because the dream will immediately break up, but this time I remarked to the girl that she wasn't real and in fact was a figment of a dream. She looked at me and said that she was and I was acting crazy. She wouldn't believe me.
So since then I've been trying to provoke my dream people by telling them they are not real to see what kind of responses I get.
In a pretty recent dream, I found myself in a huge pasture where a hot air balloon festival was taking place. A girl was sitting on a blanket eating something, so I kicked myself high into the air and glided down to first show her that I could warp the laws of physics, then I whispered in her ear that it was just a dream and she was an apparition. She smiled and said out loud, "I know this is all just a dream," at which point everyone around her just looked at me in affirmation.
I got really nervous but no one seemed to mind, so I managed to spend about half an hour talking to all sorts of people both imaginary and from my real life, having conversations about the nature of existence and dreaming and pondering on how my brain was able to create all of this in realtime. Then someone wearing all black with short cropped hair ran up to me, grabbed my by the shoulders and shook me while fervently repeating something in a language I didn't understand. Their eyes looked wild and pleading and they kept repeating the same thing over and over until they were convinced that I couldn't understand, at which point I was told another word and the figure let go and ran off into the crowd. I wasn't able to find them, but the excitement of the experience and running around got my brain amped up and things began to slowly go white. I asked a few people if they recognized the person but they didn't, and I woke up. The experience was a bit unsettling.
There was a time I was a lucid dreamer too. I did it using a simple technique my dad taught me which is to keep a notepad next to bed and every time you wake up from a dream, write everything you can remember down. Then read what you wrote before falling asleep.
Within a short time, I developed full consciousness in my dreams. I was lucid and I could even reshape my dreams while dreaming, or reenact or resume dreaming from one night to the next. I would recall every detail in full during the day. Dreams did not fade away anymore.
After a few weeks I became exhausted with dreaming, and I started dreading going to bed. Even after halting lucid dreaming practices, to this day I still have very detailed dreams I can remember for days or years. The dream anxiety from going into lucid dreaming caused me insomnia during at least 5 years.
> A recent fascination I've had the last few months is pushing boundaries with my dream characters. Several weeks ago I had a dream where I was having a conversation with someone, and paused to observe that the situation wasn't real. Normally I've found I have to keep this knowledge to myself because the dream will immediately break up, but this time I remarked to the girl that she wasn't real and in fact was a figment of a dream. She looked at me and said that she was and I was acting crazy. She wouldn't believe me.
Interesting. I met a long-dead relative once in a dream, and he told me "I'm not really here" and I said "I know" and we enjoyed the moment together.
I wonder if this kind of control over dreams can be used to do real work while dreaming (you just have to remember the solution and write it down when you wake up).
I really want to. I want to do more studying of the living subjects and environments in my dreams. I think oneirology and in turn the knowledge corpus of brain's simulation prowess is still completely in its infancy.
I've successfully solved basic arithmetic which requires mid-term memory allocation like multiplication and long division. I want to train myself to use a keyboard and type but I have back problems and often can't sleep on my back. I want to figure out a way for people to ask me questions and give me tasks.
I have experienced sleep paralysis for most of my life, I can still vividly remember the first night it happened as a small child. So I hallucinate things when I'm coming to/fro sleep.
My dreams were pretty vivid before but it was only after that when I began to train myself. But I would commonly see people, ghosts, aliens, monsters, etc. creep out of the shadows at night and touch me or just remain beside me while I was drifting off. A couple of months ago I (hopefully) hallucinated that I was visited by a succubus and it was quite tangible and vivid.
Actually yeah it's really like that sometimes lol. I've had a few dreams where everyone in the dream suddenly turns on me. And I use a lot of the same techniques for knowing if you're dreaming! I think Nolan must have consulted with lucid dreamers to know about things like the top, or coin. For me, my go-tos are light switches, a watch or any clock, looking closely at people's faces, and a bunch of other cues which signal an imperfect simulation.
Between ages 0-6 it was mostly just maze dreams, where I would be trapped in some twisty, morphing construct like a hospital or apartment building. At the time I assumed it was because I didn't have much life experience and so it was mostly visual and without social interaction, and the labyrinths represented my confusion about my surroundings and my feelings of being lost and powerless. But Inception's aesthetics and the dream mazes gave me goose bumps because of how close to home it hit!
For most of my childhood and teenage years it was overwhelmingly chase dreams. I was always running from some person or organization, and everyone was suspect. Sometimes right in the neighborhood, but often crazy blockbuster set pieces or different time periods. Lots of dreams where people realized I didn't belong and started chasing me like Inception.
Now I have a lot of dreams where I'm back in high school, or in prison, my teeth are all falling out, or a couple of other staples. Lots of reoccurring characters and locations. Last month I had a dream I was back in my elementary school, and because there were so many people I recognized and because the dream lasted uninterrupted for so many hours despite my lucidness and being aware that it wasn't reality, that I truly became convinced I had died or fallen into a coma while sleeping and was now experiencing a prolonged hallucination.
But dogs are a lot closer genetically to humans than octopuses are. Perhaps dreaming has something to do with intelligence, perhaps it has something to do with how our brain is structured.
The (very) amateur deep learning/ml developer in me wonders if these feedback loops in the brain are the key or something to the conundrum that backprop isn't neuromorphic (that we've found, last time I researched this)?
That is, everything is "feedforward" but the outputs sometimes are fed back to the inputs (both literally, and "figuratively" though physical means - ie, motor outputs move arms which the eyes see and turn back into sensory stimuli, etc)...
...I'm not naive enough to think that is an original thought, though.
It's probably more like a system which shares input at various stages of processing, and through both intentional and accidental means this information can return to other places in the network.
In other words I don't think we discretely process each sensory input on its own before propagating the result, but instead we process things in tandem, sharing intermediate information and then eventually reconstruct it all as one experience.
For example, just in a temporal sense your body receives and processes tons of sensory input coming in at various times but it "feels" like it happens all at once. When I slap your leg, you feel the impulse, see the action, and hear the impact all at once despite the wildly varying times it takes for these inputs to reach and be processed by your brain. But your brain doesn't just wait to "see" the slap until you actually feel it. Instead, your brain "error corrects" the past with new information.
It's incorrect to view your consciousness as a singular state at any given time; rather, your experience exists in a fuzzy temporal location with no well-defined boundaries. It's hard to grok but here is another example:
If you move your eyes quickly to another location [0], your brain "fakes" what you see, before replacing that information with real information. For this reason, if you sometimes look at a wall clock with a ticking (not continuous) second hand at just the right moment, the second hand seems to hover for a slight while longer before continuing its path around the clock.
So I think your brain samples and holds previous sensory information for reuse. It could recall memories to help with this, but a much faster and reliable method for experiences like a saccade or a multi-sensory event would likely be to retain recent sensory phenomena in order to reuse it in the sensory pipeline. This network simultaneously enables internal simulation and thus dreaming. That is just personal theory and I would like to test it, but theoretically it makes sense to me.
I've had this exact insight and I think it is the case.
I'll take it even further. There are delays in propagation (duh). Because of this, the loops of neurons are resonant with certain frequencies of firing rates.
Perhaps my favorite neural loop is the one that exits our skull and then reenters through the acoustic medium. If you put your speech into a microphone, through a delay line, then back into your ears it completely kills your ability to talk.
> loops of neurons are resonant with certain frequencies of firing rates
Do you hypothesize a distributed, or centrallized control mechanism for this behavior? Like a direct consequence of each neuron's encoding, or is it parameterized in a way which can be changed on-the-fly via a control circuit? Maybe both?
The brains in almost all intelligent animals, from humans to crocodiles, evolved once. The most recent common ancestor of you and the average salamander had a brain that wasn't that much different than ours. It's not particularly surprising that both dogs and humans dream, because our most recent common ancestor was only a few tens of millions of years ago.
The most recent common ancestor between humans and octopuses was hundreds of millions of years ago. That ancestor wasn't dumb the way a frog is dumb, it was dumb the way a clam is dumb. It quite literally did not have a brain.
So yes, it's weird that both octopuses and the other branch of intelligent life both dream. That's interesting, and it tells us something about intelligence. If both birds and bats, who developed flight independently, both had sonar and bad vision, that would be interesting, and would tell us something about flight.
Probably that offline training is a significant boost to an intelligent creature's fitness function? (Where all mammals and quite a few other animals qualify as 'intelligent').
The more you can learn from that near-death experience without having another one, the less likely you are to become something's lunch.
that is absolutely gorgeous. i was watching this all day yesterday...and playing Ringo's Octopus' Garden.
Cephalopod intelligence is a thing. I have often wondered if only intelligence/sentience is connected to dreaming. octopi dream..cats dream, but do insects dream?
Octopus Dreaming - https://www.youtube.com/watch?v=0vKCLJZbytU
Some of the best imagery I've ever seen of chromatophores (and other *phores) in action.