What Did Ancient Humans Do at Night? — Transcript

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1. 0:00Tonight, when the sun goes down, you're
2. 0:01going to flip a switch. Light will flood
3. 0:03the room, and you won't think twice
4. 0:04about it. But for 99.9%
5. 0:07of human history, that switch didn't
6. 0:09exist. When the sun set, the world went
7. 0:11dark. You couldn't even see your own
8. 0:13hand in front of your face. But modern
9. 0:15humans almost never experience this. For
10. 0:18over 300,000 years, every single one of
11. 0:21your ancestors spent roughly half their
12. 0:23life in near total darkness. They didn't
13. 0:25even have candles for most of that time,
14. 0:27just the black sky, the stars, and
15. 0:29whatever fire they could keep alive. So,
16. 0:31what did they actually do for all those
17. 0:32hours? The answer changes everything we
18. 0:35think we know about sleep, storytelling,
19. 0:37and what it means to be human. Let's
20. 0:39start with fire, because fire is the
21. 0:41reason any of this was possible. The
22. 0:42earliest solid evidence of humans
23. 0:44controlling fire comes from Wonderwerk
24. 0:46Cave in South Africa, roughly 1 million
25. 0:49years ago. But fire didn't just keep
26. 0:51people warm. Fire completely
27. 0:52restructured the human day. Before fire,
28. 0:55our ancestors were like every other
29. 0:56primate. When the sun went down, you
30. 0:58climbed a tree or found a sheltered
31. 1:00spot, and you stayed still. Moving at
32. 1:02night meant becoming food. Our eyes are
33. 1:04terrible in the dark compared to the
34. 1:06predators that hunted us. Leopards,
35. 1:08hyenas, wolves, all of them could see
36. 1:11just fine. Fire changed that equation
37. 1:13overnight, literally. A campfire creates
38. 1:16a circle of safety roughly 30 ft in
39. 1:18diameter. Inside that circle, predators
40. 1:20won't come. Outside that circle, you
41. 1:23die. This is not an exaggeration.
42. 1:25Anthropologists studying modern
43. 1:27hunter-gatherer groups have documented
44. 1:29that people who wander away from the
45. 1:31fire at night are significantly more
46. 1:32likely to be killed by predators, even
47. 1:34today. But here's what's fascinating.
48. 1:36Fire didn't just protect humans at
49. 1:38night. It gave them something they'd
50. 1:40never had before, extra hours. Think
51. 1:42about this. Before fire, the useful day
52. 1:45ended at sunset. That's maybe 12 hours
53. 1:47in summer, as few as eight in winter.
54. 1:49Fire suddenly added two to four usable
55. 1:51hours to every single day. And over
56. 1:53thousands of generations, those extra
57. 1:55hours changed our species. In 2014,
58. 1:58anthropologist Polly Wiessner published
59. 2:00a study in the Proceedings of the
60. 2:02National Academy of Sciences. She spent
61. 2:04years recording conversations among the
62. 2:06Ju/’hoansi Bushmen of the Kalahari
63. 2:09Desert, one of the last groups on Earth
64. 2:11still living something close to the
65. 2:12original human lifestyle. What she found
66. 2:14was striking. During the day, about 80%
67. 2:17of conversations were practical. Who's
68. 2:19hunting where? Which plants are ready?
69. 2:21Complaints, logistics, economic
70. 2:23negotiations. Daytime talk was work. But
71. 2:26at night, around the fire, the entire
72. 2:28character of conversation changed. 81%
73. 2:31of conversations were stories, tales of
74. 2:34people in distant places, adventures,
75. 2:36myths about the origins of the world,
76. 2:38jokes that made the whole camp laugh.
77. 2:40Wiessner argued that firelight
78. 2:42conversation is where human culture was
79. 2:44born. The campfire was the original
80. 2:45theater, the original classroom, the
81. 2:48original church. It's where humans
82. 2:50learned to think beyond the immediate
83. 2:51present and imagine things that don't
84. 2:53exist yet. It's where we became us. But
85. 2:56the night wasn't just about stories
86. 2:58around the fire. There was something
87. 2:59else happening, something that
88. 3:00scientists only rediscovered in the last
89. 3:0330 years. You were not designed to sleep
90. 3:05the way you sleep right now. In 2001,
91. 3:07historian Roger E. Ekirch published a
92. 3:09paper that changed sleep science. He had
93. 3:12spent 16 years digging through
94. 3:13historical records, and he found
95. 3:15something nobody expected, over 500
96. 3:17references spanning centuries, prayer
97. 3:20books from the 1400s, court records,
98. 3:23diaries, medical texts, letters from
99. 3:25ordinary people, even passages in
100. 3:27Homer's Odyssey. All of them mentioned
101. 3:29the same thing, first sleep and second
102. 3:31sleep. Before the industrial age, people
103. 3:33did not sleep in one continuous block.
104. 3:36They went to bed shortly after sunset,
105. 3:38slept for about 4 hours, then woke up.
106. 3:40They stayed awake for 1 to 2 hours in
107. 3:42the middle of the night. Then they went
108. 3:44back to sleep for another 4 hours until
109. 3:46dawn. This wasn't insomnia. This was
110. 3:48normal. This was how every human on the
111. 3:50planet slept for thousands of years. And
112. 3:52what did people do during that wakeful
113. 3:54period in the middle of the night?
114. 3:56Everything. A 16th-century French
115. 3:58physician recommended that couples
116. 3:59conceive children during this window,
117. 4:01because they would do it better. People
118. 4:03visited neighbors. They interpreted
119. 4:05their dreams while they were still
120. 4:06fresh. They wrote. They simply lay in
121. 4:08bed in the dark and thought. A doctor's
122. 4:10manual from the 1500s advised patients
123. 4:12that the best time to study and reflect
124. 4:15was during the watch, as they called it,
125. 4:17the quiet hours between first and second
126. 4:19sleep, when the mind was calm and the
127. 4:21world was still. Now, historians had
128. 4:23been reading these references for
129. 4:25centuries, but they kept translating
130. 4:27first sleep as something else, because
131. 4:30they couldn't imagine that people ever
132. 4:32slept differently than we do now. The
133. 4:34assumption was so deep that translators
134. 4:36literally mistranslated ancient Greek
135. 4:38and medieval Latin to make it fit their
136. 4:40modern experience. But then science
137. 4:42confirmed what history had been saying
138. 4:44all along. In 1992, psychiatrist Thomas
139. 4:47Wehr at the National Institute of Mental
140. 4:49Health ran an experiment. He took a
141. 4:51group of volunteers and removed all
142. 4:53artificial light from their lives. For 1
143. 4:55month, they experienced 14 hours of
144. 4:58darkness every night, just like our
145. 4:59ancestors would have before fire
146. 5:01extended the evening. Within weeks,
147. 5:03every single participant settled into
148. 5:05the same pattern, 4 hours of sleep, 1 to
149. 5:083 hours of quiet wakefulness, then 4
150. 5:10more hours of sleep. Nobody told them to
151. 5:12do this. Nobody suggested it. Their
152. 5:14bodies just did it, as if some ancient
153. 5:16program had been waiting inside them the
154. 5:17whole time, buried under centuries of
155. 5:20artificial light. Wehr measured their
156. 5:22hormone levels during the wakeful period
157. 5:24and found something remarkable. The
158. 5:25participants were in a state unlike any
159. 5:27normal waking state. Their brains were
160. 5:29producing elevated levels of prolactin,
161. 5:31the same hormone released during
162. 5:33meditation and after orgasm. They
163. 5:35described feeling peaceful, reflective,
164. 5:37almost meditative. It wasn't just a gap
165. 5:39in sleep, it was its own distinct state
166. 5:41of consciousness, one that most modern
167. 5:43humans have never experienced. So, what
168. 5:46killed it? The answer is simpler than
169. 5:48you'd think, light. In the 1600s, cities
170. 5:51began installing street lamps. Paris was
171. 5:53one of the first under Louis XIV, who
172. 5:55wanted to reduce crime. London followed.
173. 5:58The night, which had been a place of
174. 5:59danger and fear, slowly became
175. 6:01navigable. Then came cheaper candles,
176. 6:03then gas lamps in the 1800s. Then, in
177. 6:061879, Thomas Edison commercialized the
178. 6:09electric light bulb, and within a
179. 6:11generation, the night as humans had
180. 6:13known it for 300,000 years was gone. And
181. 6:15here's the part nobody talks about. The
182. 6:17word curfew comes from the French
183. 6:19couvre-feu. It literally means cover
184. 6:21fire. In medieval towns, a bell would
185. 6:24ring at night, signaling everyone to
186. 6:25cover or extinguish their fires, not
187. 6:27because of safety, because night was
188. 6:29supposed to be dark. Night was when you
189. 6:31slept. Night was when you were
190. 6:32vulnerable. For most of history, being
191. 6:34out at night was suspicious. In many
192. 6:36medieval European cities, walking
193. 6:38outside after dark without a lantern was
194. 6:40literally illegal. Night belonged to
195. 6:42criminals and the supernatural. People
196. 6:44feared it in a way that's almost
197. 6:46impossible for us to understand today.
198. 6:48And then we conquered it. We flooded it
199. 6:49with light, and we thought that was
200. 6:51progress. But here's what we lost.
201. 6:53Modern humans are exposed to artificial
202. 6:55light an average of 7 to 8 hours after
203. 6:57sunset. This light, especially the blue
204. 6:59light from screens, suppresses your
205. 7:01body's production of melatonin, the
206. 7:03hormone that regulates sleep. Your body
207. 7:05doesn't know the difference between a
208. 7:06light bulb and the sun. When light hits
209. 7:08your retina at 11:00 p.m., your brain
210. 7:10interprets it as daytime. It delays
211. 7:12melatonin release. It fragments your
212. 7:14sleep. It disrupts the circadian rhythm
213. 7:16that evolved over millions of years.
214. 7:18Researchers have found that people who
215. 7:19go camping for just 1 week with no
216. 7:21artificial light at all have their
217. 7:23melatonin cycles reset by nearly 2
218. 7:25hours. Their bodies start producing
219. 7:27melatonin at sunset instead of hours
220. 7:29after it. That's all it takes for
221. 7:31300,000 years of programming to reassert
222. 7:33itself. We didn't just change when we
223. 7:34sleep. We eliminated an entire phase of
224. 7:37human consciousness. That quiet,
225. 7:39reflective state between first and
226. 7:41second sleep, the state that Wehr's
227. 7:43subjects described as peaceful and
228. 7:44meditative, doesn't exist anymore for
229. 7:46most people. Instead, we have insomnia,
230. 7:48and we treat it like a disorder. But
231. 7:50what if it's not a disorder at all? What
232. 7:51if waking up at 2:00 a.m. and lying
233. 7:53there in the dark isn't your body
234. 7:55malfunctioning? What if it's your body
235. 7:56remembering what it was built to do? For
236. 7:58300,000 years, your ancestors spent
237. 8:01their nights in a rhythm that modern
238. 8:02science is only beginning to understand.
239. 8:04They gathered around fires and told
240. 8:06stories that built civilizations. They
241. 8:08slept in two phases with a window of
242. 8:10quiet reflection in between. They lived
243. 8:12in darkness so complete that the Milky
244. 8:14Way wasn't something you had to drive to
245. 8:16a national park to see. It was just the
246. 8:18sky. And every night when they woke in
247. 8:20the dark between first and second sleep,
248. 8:22they lay there in silence and thought
249. 8:23about their lives, their dreams, and the
250. 8:25world they would wake up to in the
251. 8:27morning. We traded all of that for a
252. 8:28light switch, and most of us never even
253. 8:30knew it was gone.