eli5 Circadian Rhythym. how do people that don’t know what time it is when they fall asleep still wake up at the same time every day?

Question

eli5 Circadian Rhythym. how do people that don’t know what time it is when they fall asleep still wake up at the same time every day?

In: 34

Answer 1

Before civilization it was just important to be up in time – you needed to wake up in time to use what daylight hours you had. The specific time of the day wasn’t as important – sure, you needed to know to some degree how late it was to plan your day, but before civilization there was simply almost no need to meet someone at a specific time when people were living in small tribes.