If i recall right in hunter-gatherer societies people were naturally divided into different sleeping schedules - some wake up at dawn, other at noon etc. The w

If i recall right in hunter-gatherer societies people were naturally divided into different sleeping schedules - some wake up at dawn, other at noon etc. The whole community was always at least partially awake. https://www.psychologytoday.com/us/blog/personal-health-mastery/201708/what-hunter-gatherers-tell-us-about-natural-sleep-patterns https://www.psychologytoday.com/us/blog/personal-health-mast...