Why People Slept Twice Every Night (And Who Woke Them Up)

It is three in the morning, and you are awake again. For most of history, that was normal. People even had words for it. They were first sleep and second sleep. In the 1990s, the historian Roger Ekirch was looking for something else. But he kept finding those two phrases, in diary after diary and court record after court record. He has now found more than 2,000 of them, in a dozen languages, going back as far as Homer. The pattern was simple. You went to bed soon after dark and slept for three or four hours. Then you lay awake for an hour or two in the quiet middle of the night, and slept again until dawn. Then came gas light, electric light, and a factory whistle that went off at the same time whatever the sky was doing. Bit by bit, the waking hour was squeezed out. Something else had to tell people when to get up, and that's how a job called the "knocker-upper" lasted into living memory. The last one in England retired in 1973, four years after the Moon landing. 00:00 It's three in the morning 00:26 The historian who found "two sleeps" 02:25 One night in the cottage 03:06 What people did in the dark hour 04:29 How anyone knew what time it was 05:17 The factory that didn't care about daylight 05:57 Tap tap tap: the knocker-upper's round 07:08 The twist: the clock replaces the body 08:00 The scientist who tested it in a lab 08:39 The last knocker-upper What we checked, and one thing that is still argued about: • In At Day's Close, Roger Ekirch listed more than 500 mentions of a "first sleep" and "second sleep". He has since found over 2,000, in a dozen languages, going back to Homer. • A French doctor in the 1500s gave couples advice on the best time to try for a baby. His answer was after the first sleep: "they have more enjoyment... and they do it better." It is a real, dated source. • In the early 1990s, Thomas Wehr at NIMH gave eight men fourteen hours of darkness a night, like a winter. Within weeks they were sleeping in two parts, without being told to. • Mary Smith of East London used a pea shooter and dried peas to wake people in the 1930s. She was paid sixpence a week per house. • The last knocker-upper in England retired in Bolton in 1973. • How common two sleeps really were is still argued about. Ekirch's view is the main one, but researchers such as Niall Boyce and Jerome Siegel disagree. They point to hunter-gatherers today who don't sleep in two parts. We say this in the film rather than call it a fixed rule. Next time: Before Pads and Tampons: What Women Used Instead. #history #sleep #circadianrhythm