I seem to hear from a variety of people that they struggle to fall asleep at night; but the difficult to fall asleep sounds like an evolutionary downside. Even as hunter-gatherers, being able to sleep whenever and wherever sounds like it would be an advantage.
Is it a recent product of modern times and people didn’t actually struggle with it a while back? In which case, what of modern life is causing this? If not, what is the evolutionary advantage of not falling asleep easily?
Years I I remember reading something about it as an evolutionary necessity. I have no reference now. Anyway it says that having in a tribe people accustomed to fall asleep at different times and in different condition allowed to have always at least one person on a watch for dangers coming from the outside. This does nor explain why people struggle to fall asleep for long hours, but at least it gives a partial explanation.