2 ms·

We know because there are still hunter gatherer societies around today. We have scientists who have spent long periods of time living with them and learning the

• ntsplnkv2 7y ago
  That is interesting - but can we really say with certainty this is how it always was? Especially since there is bias added (they know of the existence of the scientist).
  • chongli 7y ago
    We can’t say anything with certainty in science. It’s all inductive reasoning. Maybe the errors bars are bigger in some fields more than others, but that’s all we can do. I doubt archaeological evidence will ever determine the sleep schedules of teenagers from the pre-agricultural days.