I think people in HN (and in general) have to remember the central axes of evolution before digesting this kind of article. I've already seen comments like it's "odd that no species has ended up evolving a continuous maintenance system" and "sleep has a higher opportunity cost in humans" in this comments section.
This is a common, but poor framing of evolution. Remember: the only real rule with evolution is "did this evolutionary change mean they survived / reproduced more"? Evolution is not a local or global maxima solving function. I find this kind of attempt at interpreting selection common with engineers, programmers, etc.
Did their genes survive more, you mean. Hyper-vigilance could be maladaptive for the individual and still survive if it benefits others that carry the gene for it.
A bit of a digression, but I recently learned about the concept of pangenomes, of trying to map not just the genes in one individual, but the entire set of genes from a clade. It seems it matters a lot in practice for e.g. the immune system that we don't all have the same surface proteins on our cells, even if done some surface proteins are clearly better than others.
> "did this evolutionary change mean they survived / reproduced more"
You're just renaming the terms. More/less is a fitness gradient, and the thing that lives there is called an optimizer.
Evolution is a tunable-scale optimizer. It's not perfectly local, because it shotguns to avoid local optima on a (bumpy/noisy) fitness landscape. If you tune the 'shot pattern' really wide (infinite copies with infinite variation), you'd genuinely get a one-shot global optimizer at the limit. But that's not efficient nor realistic, so typically it's somewhere in between.
Uh, compare maze solvers: you've got your greedy direct route (gets stuck in the first corner) , Dijkstra (finds all the answers but takes ages), and then stuff like A*, which is a happy medium. Evolutionary algos can be used to solve mazes just the same. I think it's a bit heavier on resources than A*, but well suited to embarrassingly parallel optimization.
edit: Heh, I actually had claude build a comparative simulation. Turns out evolution is actually very slow on a single optimization axis, and gets stumped in mazes where the detour length is greater than the "temperature"/"spread"/"noise". The actual performance metrics are fascinating. But once tuned, it is able to solve mazes. Thus an optimizer. QED :-P
I'm a biologist so forgive me the poor wording, but there are "infinitely high" peaks/walls in the evolutionary landscape, as in: "the human urinary system has some evolutionary constraints and anatomical features that are not optimally designed from an engineering perspective, but they are generally functional and reflect our evolutionary history rather than deliberate design." <- this is from AI, I didn't remember the details, but the ureters or urethra take a long way around the inner part of the body because at some point it was a good route, but as we evolved it became suboptimal, but we can't just evolve to untangle all the pipes in our body and do some cable management... We're stuck with what we have (no tunneling electrons ;)).
So in that sense, a global maxima (minima?) solving function will probably not arrive at what we have, it has to take into account our evolutionary path, in its entirety (as in the whole tree.), because it is all encoded in 1 (or several) long molecules, and a radical changes would take a rewrite of many parts at the same time, which just does not happen. Maybe at some point we can do it ourselves... though I imagine there being a lot of unintended consequences in other places in the body :).
Another example is that sometimes complexity in a cell signalling cascade is simply there to get some timing right (ie delay some response), and the complexity is just there, and won't simplify by itself -> But then later the complexity may start to serve some purpose. Just like proteins that are "copypasta-ed" in the genome, leaving one copy free to mutate and attain a function, or not... etc etc.
That is the difference between global and local optima.
We're not at a local optimum though, our bodies can probably evolve to produce half the urine or something without changing the route, but there is no evolutionary pressure to do so.
Yes, but we cannot evolve to have our urinary tracts take a more efficient route (or at least the probability is exceedingly low), even though there would be pressure to do so. (Maybe I'm misunderstanding your point)
I did not know human urinary tract was suboptimal.
Are there examples of "discontinuous" evolution where a chance mutation stumbled upon a much better way to do something that allowed a species to jump the gap?
I imagine it would be very rare because chance mutations in a single individual that confer extraordinary survival / mating advantage to offset entire population would be rare like being a superman among men.
"I imagine it would be very rare because chance mutations in a single individual that confer extraordinary survival / mating advantage to offset entire population would be rare like being a superman among men."
-> This also depends on population size, if there is a bottleneck event (ie 99.99 percent of some species dying) then among the 100's of survivors perhaps there could be a superman. Either because this person got lucky, or the rest got unlucky. But in general the distribution of traits is quite continuous, given large populations.
It's also good to keep in mind that us biologists have messy definitions, ie we call specimen A and B the same species when they produce fertile offspring. Some species produce offspring but infertile (Horse-Donkey, Lion-Tiger). But what if A and B have fertile offspring and B and C do, but A and C do not? The whole definition of species falls apart (it leads to a paradox).
We have a lot of that in biology. You need to learn to deal with it (sunglasses dropping down), and assign uncertainties to terms you learn about, they are often just our attempts to name boxes on continuous, multidimensional scales.
Antibiotic resistance happens all the time (at least in our artificial world) and it's a life or death situation for the bacteria.
But you were probably asking for multicellular eukaryote organism; you may be interested in the concept of saltation https://en.wikipedia.org/wiki/Saltation_(biology) . Behind the concept of the thing itself it's interesting to think about the mechanism behind it. Regular evolution is gradual (point mutation leads to a maybe slightly different protein, which has only a relatively small scale effect but you gain or lose function over many generation), but for a saltatory evolution you most probably need radical changes in the DNA, like duplication (of a single gene, multiple gene or whole chromosome), horizontal exchanges, etc.
It's possible in plant but in animal more often than not it's not beneficial at all to have such event. Famously if you have an extra chromosome nr. 21 you get Down syndrome.
Well, what is suboptimal... One would engineer it differently, it makes a weird, seemingly unnecessary, loop around some other tracts. However, being a biologist I can also imagine that if we'd reroute the thing in someone using surgery, that person suddenly gets more infections because bacteria find their way up the tract more easily (no idea, but could be!). The point is... It's a mess based on some earlier mess, but it works, and changing one part in this mess can lead to unpredictable results.
As for "discontinuous evolution"... Again, what is discontinuous? I'm sure there are events to be found of which the probability of them occurring is so small and the effects so large that they'd fall into someone's definition of "discontinuous". But I think there is by definition no such thing as discontinuous evolution. If it occurred, it had a non-0 probability of occurring, then again, maybe the universe is infinite and everything has a non-zero probability of occurring. This is getting philosophical haha. Maybe listen to some Mindscape podcasts (Sean Caroll).
Actually rabbits eat their excrement again. That's also probably not how an engineer would make it (or an intelligent designer would design it, since we seems to be going in that direction ;) ).
no offense, but it just sounds like you don't understand local maxima in high dimensional spaces.
a suboptimal trait evolving that still provided an overall population benefit (via survival or reproduction) with further improvement close to impossible without a multitude of large changes is literally just a local maximum in that high dimensional space that maps traits to whatever success metric you're measuring.
the infinite wall you describe is not a wall in that space. actually I originally wrote its more like a wall in the derivative space but its not quite right either, those just point straight down from the maximum.
Perhaps not no, please enlighten me, where is my lack of insight?
Edit, thanx for the addition. Perhaps my issues with looking at it as "local maxima in high dimensional spaces" (even though we think of minima usually, as in a marble will find the minimum in a landscape with gravity pointing down, sorry I'm a biologist) is that with every mutation and every change in environment the landscape changes (so basically with time), is it still a useful way to think about it like that, at that point? So it not a "landscape in a high dimensional space", but rather a "high dimensional dynamic surface", like a sea?
Great question! It maybe can be, but what is the maxima that is being solved for exactly? There are usually tradeoffs, the most common and prevalent is our body's immune response. If it's under-active, we might die from an infection. If it's over-active, we get diabetes, lupus, chron's, and (probably) lots of mental health disorders.
So, it's a bit context dependent, and definitely dependent on other mutations that have occurred in other parts of your DNA. Most complex diseases are "polygenic", meaning it's a culmination of quite a few factors that would contribute to a specific good or bad outcome.
So, yes, it could be modeled as a sort very context dependent with a lot of highly correlated non-independent covariates. We do use quite a lot of statistical and ML methods to understand the genome (I work in statistical genetics), but the complexity of biology has so far proved a tough nut to crack.
I think you're correct, but only if you add "for a given environment". It's good to develop the ability to store super efficiently fat when you're a Pacific Islander and food is scarce, but this advantageous trait becomes a liability with modern and plentiful (junk) food.
see thrify gene hypothesis; I know it's not a good explanatory theory but it's a good illustration of my point
Evolution is the ultimate "good enough". Once the required threshold is passed, pressure stops. The threshold might constantly be moving due to competition, environment etc.
It can't be a global one because it is inherently local. Evolution is a process which determines the next time step (generation) from only the previous generation. It has no memory at all nor "knowledge" of other reproducing pairs.
>“No way. They’re partying all night.” But they can, because there’s no top-down pressure to go into the office at 8 a.m. They’re free to catch supplemental sleep as needed throughout the 24-hour period.
This feels like the key point to me. These societies follow their body and go to sleep when they are tried, while us in the west have to sleep at a specific time to fit our schedules.
But the article discussed here also points in that direction when it mentions the importance of people on the lookout at night. The article also mentions primitive tribes partying all night, so that is yet another direction.
There is a lack of historical writings clearly describing segmented sleep as a normal practice over monophasic sleep. If it had been the standard sleep pattern, one would expect abundant evidence for it.
Roger Ekirch’s theory, meanwhile, is based on what one could call a biased interpretation of a hand-picked selection of ambiguous sources.
>18 degrees Celsius is considered optimal for sleep depth
I'm instantly skeptical of anyone making universal statements like this, because they're certainly not true for everyone, and having looked into these and similar (f/x "ideal room/office temperature"), are based on many entangled assumptions. Most of the time I expect it's just people making after-the-fact justification for doing (or imposing) what they most prefer.
When statements like this are made usually it’s because studies would have been done comparing sleep depth at different temperatures and there would have been a statistically significant increase in sleep depth at 18 degrees Celsius in the tested group compared to groups sleeping at other temperatures.
I have no idea if that was actually done here but that’s usually how these statements are justified.
Of course we are all individuals so it may not apply to everyone but you can say that for everything in medicine. Only thing we can do is look for statistically significant differences between groups in double blind controlled studies after controlling for all other factors.
yeah probably lot of study measurements and data confirming that, I'm not skeptical about it, to me it feels like something scientifically measured proven since quite some time already. of course genetics and outliers still need to be considered.
also do you know that the body temperature decreases during sleep? based on that I simply deduce and assume the more the difference between body and room temperature the more side effects arises for sleep, of course simplifying without ignoring all the rest.
And every time I hear about an optimum, I think of the Bathtub Curve.
As I imagine the curve, I use a real bathtub. Where is the water deepest? At the drain, which is typically just under the faucet. Where is the optimal place to sit? Well, pretty much anywhere except there, because "deepest" (an optimum) isn't enough to accurately gauge "best place". But even if you can swing the faucet out of the way... where is the optimal place? Anywhere on the bottom, a broad, slow curve, as opposed to the steep walls or rim.
So, if 18 degrees C is the optimum, what's the standard deviation? I bet it's not 0.1 degrees. Could be 2 degrees - and that would mean concentrating on 18 degrees is a distraction, not a goal.
This is something evolutionary discussions don't address well, either. If a gene line (species) has a pressure to change, it can "settle" for any place on the bathtub floor (when the solution is shaped like that). This is another example of evolution not seeking an optimum; merely avoiding a pessimum (a word I just googled, and like!).
In fact, it doesn't even matter if it's a bathtub curve. Maybe it's a slope, like the amount of capsaicin a pepper plant carries to fight off fungus. More better - but it costs something to make, so just make enough to ensure survival. More fungus? Increase capsaicin production. There's no floor to this bathtub; it's a linear slant all the way down to maximum possible capsaicin content (which, amazingly, is about 10% by weight of the fruit cells!!!).
If they have no frame of reference then it seems like their general contentedness is being measured (or as another commenter indicated, their willingness to gripe.)
They're probably also less confronted with articles/videos/social media posts telling them they're doing it wrong and how they should sleep instead. Sometimes ignorance (or rather, not overthinking things) is bliss...
True. But the article mentions that the amplitude of their circadian rhythm is higher (which tells you how much a relevant measure like the amount of melatonin or body temperature varies in a 24 hour cycle), so that is an indication of better sleep. A low amplitude means less difference between sleeping and being awake.
Well probably us modern human only know the "8h sleep at night" kind of sleep, yet a lot of people would tell you whether they're satisfied or not with their sleep
I mean I can vary from 9 to 3 hours of sleep a night, and I can tell you I'd rather get 9 than 3. Just because I'm meant to get 8 hours a night doesn't mean I do
This interview feels weird to me, maybe because there's lots of places where I'm thinking there's an obvious idea that isn't raised.
Like, it seems obvious to me that sleep has a higher opportunity cost in humans than most other animals. So naturally there's more evolutionary pressure in humans to sleep more efficiently.
Is this actually true? Dunno! But it was really weird that it doesn't get brought up.
> Most importantly, when we measured their circadian function directly, small-scale communities had much higher amplitude circadian rhythms than global north populations, which I think is why they report being happy with their sleep even though it’s more fragmented.
This could explain why I feel more rested when I wake up if I take glycine before going to bed, even though I don't sleep more.
> Some emerging research suggests Earth’s magnetism matters, as well. Being barefoot on the ground versus 30 stories high in a downtown skyscraper puts you in a completely different magnetic environment.
Really? My instinctive reaction to this statement is that it's quackery. Would be very interested to see headlines appear about this if it's true.
It's definitely quackery. There's way more "natural" magnetic variation between two different cities than between a ground floor apartment and a 30th floor apartment (see magnetic declination maps), and that's even before you get into the way-more-powerful magnetic fields generated or present in a home.
This is called "grounding" or "earthing" and Wikipedia doesn't pull punches in dismissing it [0]. You can buy grounding wires for your mattress or copper rivets for your shoes.
From my tissue engineering class in undergrad my 2 cents is this is maybe 95% supplements quackery and 5% genuine mystery. You can find papers that claim EM fields have cellular interactions [1]. I don't think serious scientists will touch conventional earthing, though.
I would not jump to such conclusions, I would assume is not fully known and needs to be further understood.
on the other side, do you know we have polarized and non-polarized cells? do you know they can be affected by electromagnetism?
this two things already establish the existence of a relationship and effects between them. If we then consider that cells mechanism work based on differential of electrical or chemical potentials, and that they continuously use that for their functions, reactions or environmental compensations well...
I just think they are related and we need to understand better.
People already live in different altitudes, ie with vastly different amounts of rock between themselves and the bits of the earth that produce her magnetic field.
So colour me skeptical of this claim as well.
And while I like going barefoot for other reasons, I don't think it makes much of a difference to the magnetic fields.
> People already live in different altitudes, ie with vastly different amounts of rock between themselves and the bits of the earth that produce her magnetic field.
It's not really the same thing. Construction and especially the high content of charged metal (whether it's power conduits or plain old frame) may make a considerable difference.
Do many people sleep in such tall buildings? Obviously they exist, but I can't think of any over-20 story residential building I've ever been in. Office space, sure, but not residential.
More fragmented sleep, with people talking in the night, etc. I guess that's different from the low, unnatural, rumbles of cars and aeroplanes the majority of people have to put up with.
I tried to imitate japanese people in the public transport when i was there, meaning I managed to kinda sleep/nap with eyes closed for 10-15minutes between rides and it was astonishing.
while I understand might be a more known thing, it was surprising to try it and feel very rested after that. I'm still surprised and I wonder why not the whole world does it.
of course without the music at the stops would not be possible :P
The article title is "Where human sleep went wrong" but then the entire article is about how we sleep the best we ever have, we have the most high quality sleep, and all the fearmongering about sleep is basically wrong.
> Sleep is critical to human functioning, and yet, we sleep fewer total hours than any other ape, and are still arguably the most evolutionarily successful of the primates
> humans are weird outliers—we’re the shortest sleeping primates, yet we pack in the most REM sleep relative to this short duration
Isn't that sort of the point? Sleep is a detrimental necessity and the more efficient an organism is in needing less of it, the more effective it can be because it simply has more time to get ahead of the others?
It's still very odd that no species has ended up evolving a continuous maintenance system that can run while conscious, the benefits when hunting other animals that need sleep would be enormous, so there has to be significant evolutionary push for it. I suppose the single hemisphere sleep some marine mammals do is part of the way there, but it is at most a lazy workaround. Practically all other organs have evolved to run 24/7 for up to a century without a single break, what makes brains so universally different?
> It's still very odd that no species has ended up evolving a continuous maintenance system that can run while conscious
Great point. Afaik, our bodies do preserve energy when we sleep/rest. A few questions that needs to answered first:
- will gains of 24/7 hunting/foraging offset the extra energy costs? Lions sleep 16-20 hours a day, according to the internet.
- do continuous maintenance systems imply duplicate systems? If so, I have a hunch that even a mere 40% increase in energy expenditure would quickly undo the gains in waking hours.
> It's still very odd that no species has ended up evolving a continuous maintenance system that can run while conscious, the benefits when hunting other animals that need sleep would be enormous, so there has to be significant evolutionary push for it.
I disagree. Endurance hunters walk an animal down throughout a single day. Sleep isn't the bottleneck. Efficient bipedalism and sweat are enough.
Unihemispheric sleep has been used by cults for mind control because it puts you in a vulnerable mental state (for example https://zizians.info/#unihemispheric-sleep). So anybody reading this and interested in trying it, ensure you’ve done sufficient research first.
The fact they electrically signal via chemical analogs fuelled by immersion in nutrient bearing fluid that also accretes waste products, yet is kept separate from the primary loop of the cardiovascular system by the blood-brain barrier?
> untangle what he calls the sleep paradox: Sleep is critical to human functioning, and yet, we sleep fewer total hours than any other ape
Instead of going to Tanzania you could’ve asked a sleep scientist. Sleep length has no known correlation to brain size and is known for drastic within family variation. What’s more sleep has a high within species variation too, some sleepers can survive 4 hours, others need 8. Collectively we used to sleep 9 hours in the 20th century, but it appears shorter sleep is fine too.
TLDR: no one has any idea why sleep length varies and he won’t find his answers in antrophological studies in Tanzania, though luck, buddy
This is a common, but poor framing of evolution. Remember: the only real rule with evolution is "did this evolutionary change mean they survived / reproduced more"? Evolution is not a local or global maxima solving function. I find this kind of attempt at interpreting selection common with engineers, programmers, etc.
You're just renaming the terms. More/less is a fitness gradient, and the thing that lives there is called an optimizer.
Evolution is a tunable-scale optimizer. It's not perfectly local, because it shotguns to avoid local optima on a (bumpy/noisy) fitness landscape. If you tune the 'shot pattern' really wide (infinite copies with infinite variation), you'd genuinely get a one-shot global optimizer at the limit. But that's not efficient nor realistic, so typically it's somewhere in between.
Uh, compare maze solvers: you've got your greedy direct route (gets stuck in the first corner) , Dijkstra (finds all the answers but takes ages), and then stuff like A*, which is a happy medium. Evolutionary algos can be used to solve mazes just the same. I think it's a bit heavier on resources than A*, but well suited to embarrassingly parallel optimization.
edit: Heh, I actually had claude build a comparative simulation. Turns out evolution is actually very slow on a single optimization axis, and gets stumped in mazes where the detour length is greater than the "temperature"/"spread"/"noise". The actual performance metrics are fascinating. But once tuned, it is able to solve mazes. Thus an optimizer. QED :-P
So in that sense, a global maxima (minima?) solving function will probably not arrive at what we have, it has to take into account our evolutionary path, in its entirety (as in the whole tree.), because it is all encoded in 1 (or several) long molecules, and a radical changes would take a rewrite of many parts at the same time, which just does not happen. Maybe at some point we can do it ourselves... though I imagine there being a lot of unintended consequences in other places in the body :).
Another example is that sometimes complexity in a cell signalling cascade is simply there to get some timing right (ie delay some response), and the complexity is just there, and won't simplify by itself -> But then later the complexity may start to serve some purpose. Just like proteins that are "copypasta-ed" in the genome, leaving one copy free to mutate and attain a function, or not... etc etc.
https://futurism.com/evolutianary-proof-the-recurrent-laryng...
I did not know human urinary tract was suboptimal.
Are there examples of "discontinuous" evolution where a chance mutation stumbled upon a much better way to do something that allowed a species to jump the gap?
I imagine it would be very rare because chance mutations in a single individual that confer extraordinary survival / mating advantage to offset entire population would be rare like being a superman among men.
-> This also depends on population size, if there is a bottleneck event (ie 99.99 percent of some species dying) then among the 100's of survivors perhaps there could be a superman. Either because this person got lucky, or the rest got unlucky. But in general the distribution of traits is quite continuous, given large populations.
It's also good to keep in mind that us biologists have messy definitions, ie we call specimen A and B the same species when they produce fertile offspring. Some species produce offspring but infertile (Horse-Donkey, Lion-Tiger). But what if A and B have fertile offspring and B and C do, but A and C do not? The whole definition of species falls apart (it leads to a paradox).
We have a lot of that in biology. You need to learn to deal with it (sunglasses dropping down), and assign uncertainties to terms you learn about, they are often just our attempts to name boxes on continuous, multidimensional scales.
But you were probably asking for multicellular eukaryote organism; you may be interested in the concept of saltation https://en.wikipedia.org/wiki/Saltation_(biology) . Behind the concept of the thing itself it's interesting to think about the mechanism behind it. Regular evolution is gradual (point mutation leads to a maybe slightly different protein, which has only a relatively small scale effect but you gain or lose function over many generation), but for a saltatory evolution you most probably need radical changes in the DNA, like duplication (of a single gene, multiple gene or whole chromosome), horizontal exchanges, etc.
It's possible in plant but in animal more often than not it's not beneficial at all to have such event. Famously if you have an extra chromosome nr. 21 you get Down syndrome.
As for "discontinuous evolution"... Again, what is discontinuous? I'm sure there are events to be found of which the probability of them occurring is so small and the effects so large that they'd fall into someone's definition of "discontinuous". But I think there is by definition no such thing as discontinuous evolution. If it occurred, it had a non-0 probability of occurring, then again, maybe the universe is infinite and everything has a non-zero probability of occurring. This is getting philosophical haha. Maybe listen to some Mindscape podcasts (Sean Caroll).
Actually rabbits eat their excrement again. That's also probably not how an engineer would make it (or an intelligent designer would design it, since we seems to be going in that direction ;) ).
a suboptimal trait evolving that still provided an overall population benefit (via survival or reproduction) with further improvement close to impossible without a multitude of large changes is literally just a local maximum in that high dimensional space that maps traits to whatever success metric you're measuring.
the infinite wall you describe is not a wall in that space. actually I originally wrote its more like a wall in the derivative space but its not quite right either, those just point straight down from the maximum.
Edit, thanx for the addition. Perhaps my issues with looking at it as "local maxima in high dimensional spaces" (even though we think of minima usually, as in a marble will find the minimum in a landscape with gravity pointing down, sorry I'm a biologist) is that with every mutation and every change in environment the landscape changes (so basically with time), is it still a useful way to think about it like that, at that point? So it not a "landscape in a high dimensional space", but rather a "high dimensional dynamic surface", like a sea?
So, it's a bit context dependent, and definitely dependent on other mutations that have occurred in other parts of your DNA. Most complex diseases are "polygenic", meaning it's a culmination of quite a few factors that would contribute to a specific good or bad outcome.
So, yes, it could be modeled as a sort very context dependent with a lot of highly correlated non-independent covariates. We do use quite a lot of statistical and ML methods to understand the genome (I work in statistical genetics), but the complexity of biology has so far proved a tough nut to crack.
Survival rate/reproduction rate/rate of genes being spread?
see thrify gene hypothesis; I know it's not a good explanatory theory but it's a good illustration of my point
This feels like the key point to me. These societies follow their body and go to sleep when they are tried, while us in the west have to sleep at a specific time to fit our schedules.
Does that have stronger historical backing?
Roger Ekirch’s theory, meanwhile, is based on what one could call a biased interpretation of a hand-picked selection of ambiguous sources.
I'm instantly skeptical of anyone making universal statements like this, because they're certainly not true for everyone, and having looked into these and similar (f/x "ideal room/office temperature"), are based on many entangled assumptions. Most of the time I expect it's just people making after-the-fact justification for doing (or imposing) what they most prefer.
I have no idea if that was actually done here but that’s usually how these statements are justified.
Of course we are all individuals so it may not apply to everyone but you can say that for everything in medicine. Only thing we can do is look for statistically significant differences between groups in double blind controlled studies after controlling for all other factors.
also do you know that the body temperature decreases during sleep? based on that I simply deduce and assume the more the difference between body and room temperature the more side effects arises for sleep, of course simplifying without ignoring all the rest.
As I imagine the curve, I use a real bathtub. Where is the water deepest? At the drain, which is typically just under the faucet. Where is the optimal place to sit? Well, pretty much anywhere except there, because "deepest" (an optimum) isn't enough to accurately gauge "best place". But even if you can swing the faucet out of the way... where is the optimal place? Anywhere on the bottom, a broad, slow curve, as opposed to the steep walls or rim.
So, if 18 degrees C is the optimum, what's the standard deviation? I bet it's not 0.1 degrees. Could be 2 degrees - and that would mean concentrating on 18 degrees is a distraction, not a goal.
This is something evolutionary discussions don't address well, either. If a gene line (species) has a pressure to change, it can "settle" for any place on the bathtub floor (when the solution is shaped like that). This is another example of evolution not seeking an optimum; merely avoiding a pessimum (a word I just googled, and like!).
In fact, it doesn't even matter if it's a bathtub curve. Maybe it's a slope, like the amount of capsaicin a pepper plant carries to fight off fungus. More better - but it costs something to make, so just make enough to ensure survival. More fungus? Increase capsaicin production. There's no floor to this bathtub; it's a linear slant all the way down to maximum possible capsaicin content (which, amazingly, is about 10% by weight of the fruit cells!!!).
And why wouldn't they? This is (presumably) the only kind of sleep they know.
Even in your example, you propose an individual could know multiple kinds of after-sleep feelings.
Also, we humans can get used to a lot of things and just be okay with it. For an extreme example, look at domestic abuse victims...
Like, it seems obvious to me that sleep has a higher opportunity cost in humans than most other animals. So naturally there's more evolutionary pressure in humans to sleep more efficiently.
Is this actually true? Dunno! But it was really weird that it doesn't get brought up.
This could explain why I feel more rested when I wake up if I take glycine before going to bed, even though I don't sleep more.
Really? My instinctive reaction to this statement is that it's quackery. Would be very interested to see headlines appear about this if it's true.
From my tissue engineering class in undergrad my 2 cents is this is maybe 95% supplements quackery and 5% genuine mystery. You can find papers that claim EM fields have cellular interactions [1]. I don't think serious scientists will touch conventional earthing, though.
[0]: https://en.wikipedia.org/wiki/Energy_medicine#Earthing
[1]: https://pubmed.ncbi.nlm.nih.gov/38068954/
on the other side, do you know we have polarized and non-polarized cells? do you know they can be affected by electromagnetism?
this two things already establish the existence of a relationship and effects between them. If we then consider that cells mechanism work based on differential of electrical or chemical potentials, and that they continuously use that for their functions, reactions or environmental compensations well...
I just think they are related and we need to understand better.
https://news.ycombinator.com/item?id=49360307
even mechanical of course :)
So colour me skeptical of this claim as well.
And while I like going barefoot for other reasons, I don't think it makes much of a difference to the magnetic fields.
It's not really the same thing. Construction and especially the high content of charged metal (whether it's power conduits or plain old frame) may make a considerable difference.
What about the metal frame of a bed?
https://www.pbs.org/newshour/science/dogs-poop-in-alignment-...
but then again maybe not
https://www.sciencedirect.com/science/article/abs/pii/S15587...
while I understand might be a more known thing, it was surprising to try it and feel very rested after that. I'm still surprised and I wonder why not the whole world does it.
of course without the music at the stops would not be possible :P
> humans are weird outliers—we’re the shortest sleeping primates, yet we pack in the most REM sleep relative to this short duration
Isn't that sort of the point? Sleep is a detrimental necessity and the more efficient an organism is in needing less of it, the more effective it can be because it simply has more time to get ahead of the others?
It's still very odd that no species has ended up evolving a continuous maintenance system that can run while conscious, the benefits when hunting other animals that need sleep would be enormous, so there has to be significant evolutionary push for it. I suppose the single hemisphere sleep some marine mammals do is part of the way there, but it is at most a lazy workaround. Practically all other organs have evolved to run 24/7 for up to a century without a single break, what makes brains so universally different?
- will gains of 24/7 hunting/foraging offset the extra energy costs? Lions sleep 16-20 hours a day, according to the internet.
- do continuous maintenance systems imply duplicate systems? If so, I have a hunch that even a mere 40% increase in energy expenditure would quickly undo the gains in waking hours.
I disagree. Endurance hunters walk an animal down throughout a single day. Sleep isn't the bottleneck. Efficient bipedalism and sweat are enough.
Instead of going to Tanzania you could’ve asked a sleep scientist. Sleep length has no known correlation to brain size and is known for drastic within family variation. What’s more sleep has a high within species variation too, some sleepers can survive 4 hours, others need 8. Collectively we used to sleep 9 hours in the 20th century, but it appears shorter sleep is fine too. TLDR: no one has any idea why sleep length varies and he won’t find his answers in antrophological studies in Tanzania, though luck, buddy