If you look at how humans tend to want to sleep, it seems to be either, you know, sort of a monophasic way or at least a biphasic way, where there's, perhaps, a long bout during the night and then maybe a siesta-like pattern during the day.

As you try to tweak your sleep one way or the other, you might be, you might be doing great - you might do better at remembering details of an event, but you might end up being poorer at abstracting the gist or the rules associated with it.

The fact that we don't have that biologic pressure to have highly polyphasic sleep, I think, probably tells us something in terms of, truly, whether it's useful or not.

Matthew Walker Quotes