Why Humans Sleep Less Than Any Other Primate
Where Human Sleep Went Wrong
Evolutionary anthropologist David Samson argues that human sleep is uniquely short and REM-heavy, a paradox shaped by our ancestors' shift from trees to ground sleep. In his book The Sleepless Ape, he explains how fire, shelter, and social structures enabled this evolution. He challenges the idea that modern sleep is broken, suggesting that small-scale societies' fragmented sleep is healthy due to strong circadian rhythms. Samson advocates for more outdoor time and better circadian alignment rather than a return to paleo sleep.
REM sleep functions almost like a nightly behavioral therapist.
- hastily3114
>“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.
- duskdozer
>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.
- fhn
"we’re the shortest sleeping primates, yet we pack in the most REM sleep relative to this short duration."
Nothing surprising here. We sleep in cozy comfortable beds in a locked and secure location. Of course we'd can get int REM sleep. Compare to other primates who sleep outside with the critters and predators, deep sleep could mean the end of them.
- i_love_limes
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.
- hlynurd
>the Hadza uniformly reported high satisfaction with their sleep.
And why wouldn't they? This is (presumably) the only kind of sleep they know.
- syllogism
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.
- Flashtoo
> 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.
- mark_something
> 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.