>>34768086Nope, you can look it up easily enough. Sleep Foundation has a section on it, as do plenty research articles. Prior to the industrial revolution and artificial lighting, biphasic sleep was predominant in areas where night lasted >8 hours, because waking up with an hour or more of darkness left eats into the wakeful period of the day. By splitting the sleep schedule, you are able to wake up as the sun comes up and get right to whatever you day is.
The wakeful period in the middle was limited to things you could do with minimal light, which meant checking on family/surroundings, minor chores or hobbies, and of course, sex.
