I really wonder what this says about children who wake up in the middle of the night, and the effect on parents. If you follow through with "everyone did segmented sleep", then at least the parents of children might be somewhat mismatched. Children wake up earlier, or take longer to wind back down to sleep. Is that still segmented sleep in the same vein? Maybe it was at one time natural for everyone to wake up at the same time basically, because they were so close together.

Either way, the explicit no children "rule" for experimenting with segmented sleep is an interesting thing to think about.

Of course, 9-5 jobs make it practically impossible anyway, which are assumed to go along with children in many cases