The brain truly is a system with terrible service availability. On average, after running for just 16 hours, it must be offlined for 8 hours to run maintenance tasks such as "scrub", "garbage collect", "trim", and "fsck".
> The brain truly is a system with terrible service availability. On average, after running for just 16 hours, it must be offlined for 8 hours to run maintenance tasks such as "scrub", "garbage collect", "trim", and "fsck".
It's a trade-off. The brain is about as large as it can be while making birth possible. It already uses a lot of energy(2% of body weight, 20% of energy consumption). We also need it to be working at peak performance when we are doing activities.
A background 'scrub' task to keep it working 24/7 would probably use more energy (require more food and heat dissipation 24/7), possibly require a larger area (for redundancy, similar to how dolphins can sleep one hemisphere at a time and have really large brains). An alternative would be to slow down processes enough so that those tasks could happen constantly.
And then our day/light cycles helped select for this approach. Until recently there wasn't much one could do (safely!) at night.
> The brain is about as large as it can be while making birth possible.
I wonder if it had been beneficial to have larger brains, we'd have evolved to support that. Diminishing returns maybe or just a local maximum we didn't get out of?
So how evolution works is that a feature needs to have an evolutionary advantage, but the specimen must also not die. So there are two adversarial pressures here, carefully balancing each other in a mammal species that already has one of the highest birth mortality rates of both mother and child. If heads were any larger, it would create a proportional amount of negative evolutionary pressure by both direct and indirect death (of the mother) at birth.
That's a fascinating thought. As people with larger brains are more successful in life and more likely to have children*, mortality rates for natural births would increase, and over time we would evolve to become dependent upon modern technology.
The continued existence of our species would become dependent upon continued civilisation. A dark age could kill us, or at least cripple the population.
*how true is this? Uni-educated people tend to have lower fertility rates.
If maternal mortality were the only issue, evolutionary pressure would also favor women with wider hips/birthing canals. After all, we see hyper intelligent individuals at the current brain size, it's clearly possible to get more processing power in there but there doesn't seem to be much reproductive benefit.
Beneficial kinda just means "leads to more procreation" right?
So if bigger brains meant people reproducing more, our brains would get bigger to the point that most births are cesarean or something.
I do wonder what happens when we eventually evolve to a point where we can't survive without more and more advanced technology.
A lot of people who would have died off before reproducing 200 years ago now don't, which is of course incredible for us. But what are effects of that 100/1000 years down the line?
Presumably we'll have plenty of more immediately pressing issues over that time frame.
It is interesting from a space-faring species perspective.
By the time we can embark to other planets/asteroids our biology might require us to lug around significantly more technology just to survive.
You've got it all wrong, and LLMs have it all correct.
True brains, after 16hrs of actual work, need to hallucinate strongly for 8 hours or so, in order to continue their high level contributions to society.
Interesting. What if that is actually a beneficial part of our own development: comparing the nonsense in our dreams to waking life and building the ability to tell the difference?
Get an LLM to dream, and to use the time effectively to purge those hallucinations, and reinforce the "valid and true" memories, and you might have something there ?
>The brain truly is a system with terrible service availability
Taking this as a jumping off point for a way of thinking about those 'services'. It seems remarkable to me that we can initiate the attempt to think of an elephant, and then get there in one shot. We don't sort through, say, rhinos, hippos, cars, trucks. We don't seem to have to rummage.
Of course when it comes to things on the edge of our memory or the edge of our understanding, there's a lot of rummaging. But it could have been the case that everything was that way (perhaps it is that way for some animals), instead, there are some things to which we have nearly automatic, seemingly instant recall.
This makes me think of how my dog reacts very quickly, of course, for hard-wired "dog" behavior things, but when I use human language and gestures to communicate something to him, such as "go find Daddy", I can figuratively see a loading spinner over his head for several seconds, until the recognition comes and he responds. I don't know what's going on in that head, but it definitely appears to be "rummaging" from the outside. Probably similar to how we feel when conversing in a foreign language we're not fluent in.
We don't actually know if 1/3rd downtime is a requirement. For most of our evolutionary history, it has not been economical to remain awake at night, so our intense sleep drive may actually be driven primarily by conservation of energy (since energy has been a major engineering constraint for all of our evolutionary history minus the last several hundred years or so). If that's the case, then with other processes may have evolved to fit themselves into our sleeping time as an optimization, but perhaps those processes could happen while we're awake if our evolutionary constraints were different.
>it has not been economical to remain awake at night
Why? If you can gather fruits or hunt pray while all your competitors (or predators!) are asleep, isn't it an advantage? What about nocturnality? https://en.wikipedia.org/wiki/Nocturnality
At night it is harder to see food. It is harder to see predators, some of whom are in fact nocturnal. It is harder to notice visual cues and gestures from allies/kin. It is harder to navigate, both due to difficulty seeing distant landmarks and nearby obstructions, so you are more likely to get lost and/or injured. It is colder so your body has to spend more calories to keep you warm.
There are adaptations that can improve nocturnal capabilities, but these typically come with tradeoffs that make diurnal life harder. Evolution is a series of many baby steps - either you need to adapt to not sleeping while you're still at a disadvantage at night, or you need to adapt to being awake at night while you still need to sleep. Neither path seems like it would have been advantageous to our ancestors.
If it were biologically possible, other organisms would have evolved that capability. There’s some fundamental, biological reason why all animals sleep.
Again, we don’t know that. It could easily be that the adaptations needed to operate well at night (in addition to during the day) just aren’t worth the energetic cost or they entail a large morphological compromise. The thing about evolution is it doesn’t give you its reasons.
Exactly, evolution also will leave things at "good enough for function". It may well be that our sleep cycle so happened to level off at "good enough" considering our other evolutionary constraints.
Definitely an area of study that seems interesting to me.
I did a polyphasic sleep cycle in college (2010's) for 6 months out of necessity and it worked really well.
The way I got it to work was by meticulously tracking my REM sleep. I would have sliding 3-4 hour windows to hit REM sleep and if I didn't, it just felt like a sluggish day, not any worse than being woken up by a fire alarm at 4am or a long thursday night.
> The brain truly is a system with terrible service availability. On average, after running for just 16 hours, it must be offlined for 8 hours to run maintenance tasks such as "scrub", "garbage collect", "trim", and "fsck".
There's hope. If the carbon chauvinists can be prevented from messing things up, AI is on track to provide something with a better SLA, which will finally allow us to decommission and junk those troublesome legacy systems without disrupting the business.
At all times, every single one of the billions of participants acts like a bureaucrat, delaying response until it's unavoidable and then resting afterwards at least half the time. If only we could cut through the bureaucracy!
I believe it is not only garbage collecting. It is also doing backpropagation on the memories of the day before. After 8 hours you get an updated, more optimized service.
This is the insight missing from everyone comparing LLM parameter counts to human neurons or synapses. The human model gets a new version every day, and the digital one costs $5B of energy and a year to do the same.
I also wonder why cats sleep so much. Is it mainly because there’s nothing for them to do during the day, so why not sleep? Whereas humans can be active all day?
Carnivores tend to sleep longer than omnivores, who tend to sleep longer than herbivores. For a hunting carnivore, energy comes in big bursts, so it makes sense that they would be active for a short period of time, and hoard energy when they didn't need to be active. For a cud-chewing herbivore, time spent not chewing is time spent not creating energy.
Obviously, this is a broad generalization - feeding habits, day/night cycles, predator/prey behaviors all factor into a particular animal. But it probably explains why your cat, like the panther at the zoo, spends most of its time asleep.
