Ancient humans did not sleep continuously. They commonly slept in two shifts each night, separated by a period of wakefulness ...
As researchers revisit diaries, court records, medical texts, and modern sleep experiments, a more complicated picture of human rest is emerging. I find that the story of first and second sleep is not ...
It's a commonly held belief that before artificial lighting, human sleep was 'naturally' divided into two distinct periods, but how true is that?