[notahacker]

I don't know about commonly thought to be false because I'm not sure it's commonly thought about at all, but it's a theory with considerable weaknesses

Ekirch hypothesis: Early humans had two distinct phases of sleep with an important gap between. Lack of in-depth discussion or even a name for that gap in any language is actually evidence of it being so common it wasn't worth commenting on. It disappeared - again without comment - because of widely available artificial light, although it actually makes less sense to dedicate midnight hours to stuff like household chores and reading in the middle of the night without easy light sources, especially in northern European summer when it's about the only time there isn't daylight.

Null hypothesis: early humans slept much like today's humans, sometimes waking or being woken in the night, occasionally even intentionally but generally not making a big deal of it and trying to sleep through. People sometimes described periods of broken sleep as "first sleep", "second sleep" and even "third sleep" but commentary on the practise of biphasic sleep and importance of midnight waking is harder to find because most people didn't do it that way. A lot of references to "first sleep" can be found if you search digitized records with that string and its foreign language equivalents, but so can references to obviously non-systematic things like "first injury" or "first marriage". You can't generalise human behaviour in the absence of electricity from one tribe that does have a midnight break when numerous others studied don't.

[sooheon]

> Null hypothesis: early humans slept much like today's humans [...]

That's a terrible null hypothesis, as there is no reproducible, controllable test for it, other than a time machine.

A better one might be "people exposed to pre-industrial revolution photoperiods (<12h per day) will settle into a biphasic sleep pattern".

This was empirically tested with a small N (https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2869.1992...). At least it's testable.

[notahacker]

Specifying that as something isn't directly testable, it's better that a bold new theory should actually be the null hypothesis isn't how science works! We've observed a lot of populations with little or no natural light and there is no reason to cherry pick the one or two which actually conform to Ekirch's proposed "standard" form of sleep. I mean, for a start, assuming "pre industrial revolution photoperiods" generally matched the ones in Wehr's study involves pretending that seasons don't exist in most of the places Ekirch's soured material came from!

[axiolite]

A much better study:

https://www.theatlantic.com/science/archive/2015/10/the-many...

[sooheon]

Better in what dimension? It's not a repeatable intervention, it's not controlled, it's observational. It's not a study on the same null hypothesis.

[notahacker]

If your claim concerns common habits of populations with limited or no artificial light sources, observational studies of multiple populations with no artificial light sources is a superior way of assessing it than a prior study which imposed very specific periods of light deprivation on a study sample accustomed to nightly routines governed by available light to see how their behaviour changed.

[int_19h]

> A lot of references to "first sleep" can be found if you search digitized records with that string and its foreign language equivalents, but so can references to obviously non-systematic things like "first injury" or "first marriage"

This hypothesis would also have to explain why we don't say things like "first sleep" anymore, even though we do say things like "first injury" or "first marriage".

[notahacker]

We don't talk about first sleeps but you'll still find plenty of modern references to "first sleep", "second sleep" and even "third sleep" in modern text too, from book titles to scholarly articles on sleep cycles

[jfengel]

It has always struck me as an unlikely hypothesis. While I'm not a historian, I do get some insight into the Elizabethan period in particular by a very close familiarity with its plays. Shakespeare never mentions it, and he does talk about sleep quite a bit.

One example that comes to mind, from Henry V:

    But, like a lackey, from the rise to set
    Sweats in the eye of Phoebus and all night
    Sleeps in Elysium

Hal doesn't say "All night sleeps in Elysium except for that bit where he wakes up in the middle of it". He's explicitly referring to untroubled, continuous sleep for most people (as compared to his own insomnia from worry about his kingdom).

I haven't done an exhaustive survey, but I don't believe Shakespeare characters ever wake in the middle of the night unless there is something to disturb them. They may drink late, or chimneys may come crashing down around them, but nobody ever says "Hey, see you in a few hours when we're both awake".

This is obviously far from conclusive. But the man writes about sleep often enough that I'd have expected at least some hint of it.

[wolverine876]

> Early humans

This article is about the 17th century (with some references going back further). Does Ekirch write also about early homo sapiens? Earlier ancestors? I am not nitpicking, just wondering if that term is used intentionally.

[Izkata]

> or even a name for that gap

From the article:

> The period of wakefulness that followed was known as "the watch"

Other terms for that time of night:

The witching hour (which almost sounds like a corruption of "the watch") - https://en.wikipedia.org/wiki/Witching_hour

Wee small hours - https://en.wiktionary.org/wiki/wee_small_hours

[notahacker]

Erkich's own words, both his original paper and his website, acknowledge the lack of a distinct name. He suggested generic terms "watch" and "watching" may have been used throughout a long period of British history to describe the hypothesised universal period of wakefulness based on one primary source each. One appears to be a prayer which refers to "between one morning watch and another" without hinting what a "morning watch" is, another is a devotional text calling on people to watch their first waking thoughts are set on God, where there are rather obvious alternative interpretations of the words "watch" and "first"...

The notion of "witching hour" is predicated on the idea that spirit activity takes place when most people are asleep, and "the wee small hours" is a reference to the entire period between midnight and dawn. If the closest word a language had to "lunch" was "afternoon", I'd probably conclude that culture generally didn't have an important midday meal!

https://sites.oxy.edu/clint/physio/article/SleepWeHaveLostPr... https://sites.google.com/vt.edu/roger-ekirch/sleep-research/...