Why would you assume that it's a cultural norm? I don't drink any caffeine but regularly stay up until 4 or 5am. It's simply when I feel most productive and is

Why would you assume that it's a cultural norm? I don't drink any caffeine but regularly stay up until 4 or 5am. It's simply when I feel most productive and is totally natural for me. It seems pretty clear that the opposite (early rising) is the cultural norm which is getting pushed. There are many times in my life where I'm forced to revert to waking up at 8am, but as soon as I'm back in control of my time I'll revert to a 4am–10am sleep schedule. I hardly think that's due to fulfilling some abstract cultural norm. People are different. Sleep schedules shouldn't be a morality play.