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.
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.
And why wouldn't they? This is (presumably) the only kind of sleep they know.
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.
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.
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.
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.
> 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?
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 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.