the science of

so get this: before artificial light allowed humans to control working hours, the landscape of sleep was entirely different.  people would go to sleep several hours after dusk – say 9pm – and sleep for a full sleep cycle, about 4 hours, in what was in many european cultures called first sleep.  they would then awaken at around 1am and spend the next few hours in quiet domesticity – reflecting, talking, fornicating – until they fell asleep again at around 3 or 4am and slept another full sleep cycle, the second, or morning, sleep.  it’s notable that this schedule was obvious to pre-moderns, which places historical writings about evening activities in a slightly different context than the modern reader might expect.  it seems to have been true of humans forever, and what few contemporary pre-industrial cultures remain exhibit similar behavior.  even modern adults with strong circadian rhythms cannot help but follow this same structure.

what’s the difference between sleeping in two distinct periods, rather than combining it into one long stretch?  perhaps, in our constant quest for efficiency, we’ve simply found a way to make the same sleep occupy less time, all other differences be damned?  studies of modern people forced to follow pre-modern light schedules for extended periods of time – which show that they naturally adopt the pre-modern sleep schedule after a few days – also show that the period of early wakefulness features a hormonal response unlike that of any other time in the day.  melatonin and prolactin levels create a period most analogous to meditation, giving night wakers a sense of euphoric peace and contentment.  historical writings confirm that this late-night interval was an essential component of balanced mental health, shedding the weight of the day and rebuilding the spirit.

these were also bleary-eyed times between true sleep and true wakefulness, and many writings record the dreams from these intervals as particularly clear and vivid, possibly contributing to the pre-modern faith in the importance and relevance of dreams.  people were spending hours a day in a state that couldn’t be said to be sleep, experiencing strong, vivid dreams – it makes sense to understand these more as external visions, granted by something outside oneself, than as modern people do, as entirely internal creations.  incidents of lucid dreaming were also frequent, with people taking a much more active role in their dream narratives.

so, bottom line: it’s possible that people were happier, and less neurotic, and in some ways more spiritual, all because of this segmented sleep schedule – the very same schedule that, in modern americans, has yielded ambien and lunesta, rozerem and sonata.