What Ancient Humans Did All Night?

What Ancient Humans Did All Night? How did ancient humans sleep at night with no light? Early humans, hunter gatherers, first sleep and second sleep, and why ancient humans woke up at 3am. Your body was built for long, dark nights. For about 300,000 years there was no switch to reach for. When the sun went down, the world simply disappeared. The answer: a campfire that became the first theater and the first classroom, stories that made up most of what people said after dark, a night watch built into the group — and one strange habit most of us have forgotten: sleeping in two parts, with a calm hour awake in between. CHAPTERS 0:00 A world with no light switch 0:50 How fire rebuilt the human day 2:00 What people talked about after dark 3:15 First sleep and second sleep 4:40 The experiment: 14 hours of darkness 5:35 Did all humans sleep this way? 6:05 How light killed the second sleep 7:05 What screens do to your body 7:50 Why you wake up at 2 a.m. SOURCES Berna et al. (2012), PNAS — one-million-year-old fire at Wonderwerk Cave Wiessner (2014), PNAS — firelight talk among the Ju/'hoansi Ekirch (2001), American Historical Review — first sleep and second sleep Wehr (1992), Journal of Sleep Research — sleep under long nights Yetish et al. (2015), Current Biology — sleep in three hunter-gatherer societies Samson et al. (2017), Proceedings of the Royal Society B — the Hadza "night watch" Wright et al. (2013), Current Biology — camping and the natural light-dark cycle Ancestor Files — simple stories about the people who came before us. New videos every week. #ancienthumans #sleep #prehistory