we must have always needed night owl and early riser humans to serve as watchers of our sleeping civilizations for hundreds of thousands, if not millions of years, and our genome is adapted to the need. Do you think so?

Last theory I heard it's why we have depressed people and asperger/autism: all qualities fitted to perform some edge functionalities (being alone at night, extreme dedication to problem solving,etc.).

Anyway, seriously: just because our genomes stir us to it doesn't mean it's good for the individual.

Rest of the tribe is asleep, we’re the ones keeping watch while the stars are out, left to our own thoughts.

I think screens just keep us awake as I.T. workers. Unnatural as ever, much more probable in my opinion.

But then the tribe is on the move and a few need to sleep. I think a mostly synchronised schedule is more likely.

There’s a potential study for someone out there - see if descendants of nomadic tribes have less of a variance in circadian rhythms as opposed to people descending from static tribes.