History

Can't Sleep Through The Night? You'd Feel Right At Home In The Pre-Industrial Age

If you're one of the third of Americans who have some trouble staying asleep through the night, we have good news. Humans haven't always slept through the night in one long doze. Up until the Industrial Revolution, "segmented sleep" was incredibly common.

Related: The 4 Qualities Of A Good Night's Sleep, According To Sleep Experts

Historian A. Roger Ekirch brought the trend of segmented sleep to light in 2001. His findings revealed that people used to divide their sleep into two separate periods, often referred to as "first sleep" and "second sleep." Between these periods, people would do chores, read, pray, or even go outside to visit friends.

Related: Why You Should Sleep In A Cold Bedroom

Ekirch delved further into this phenomenon by studying modern non-Western cultures, including indigenous communities in Nigeria, Central America, and Brazil. He found that many of them also slept in segments. "During the period of nighttime wakefulness, Ekirch showed, different cultures elaborated rituals—of prayer, lovemaking, dream interpretation, or security checks—and while the rituals varied, the pattern itself was so pervasive as to suggest an evolutionary basis that somehow became disrupted in the modern West," Benjamin Reiss writes in New York Magazine.

Related: Sleeping In Can Be Too Much Of A Good Thing

What Changed?

There are a few elements Ekirch points to that may have caused this radical shift in our sleep schedules, but the most prominent is the electric light. Before artificial lighting, you had to turn in when the sun went down, since it was too dark to see what you were doing. But once powerful light came on the scene, more and more activities were possible later and later into the night, so bedtime got later and later. Wake-up times didn't, so something had to give, leading to the shrinking and eventual disappearance of that waking time between first and second sleeps. Modern experiments support his theory: experiments in 1993 by psychiatrist Thomas Wehr showed that when people were deprived of artificial lighting for long periods of time, they began to wake up for a period in the middle of the night. So if you're having trouble sleeping, take consolation in the fact that you'd feel completely normal in the 1600s.

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Key Facts In This Video

  1. There is no solid scientific consensus on why we sleep. 01:56

  2. Black rhinos sleep for one to two hours laying down, and three to four hours standing up. 04:23

  3. Dolphins engage in unihemispheric sleep, which means that one half of the brain is resting while the other half is alert. 08:01

Written By Curiosity Staff August 12, 2015