Evolution and sleep

[KidDreamer]

I have a question that Im not completely sure can be answered but I would like input on it. Okay, so you know how theres that perfect amount of sleep that someone can get for them to feel great? and how oversleeping isnt really that helpful/not getting enough sleep has the same effect? Well I was wondering, from an evolutionary standpoint, why dont our bodies just wake us up when we achieve our individual amounts of perfect sleep? wouldnt it make sense for them to want to get up instead of sleeping longer and inevitably feeling worse?

[Talgoran]

You know, that's a very good question.

[Mr_Jinsue]

Perhaps its the short term pleasure winning out over the (slightly) longer term tiredness from oversleeping. The pleasure of it being relaxing/dreaming/memories. I would say its probably better to be able to oversleep. At least this way we have the option. If we just 'woke up' that could get annoying. I know myself that I am a 10hours sleep person though. At some point after the 10hour mark I do something of a spontaneous wake up, where my eyelids open and it requires more effort to keep them shut than let them stay open. Good question though.

[Lakona]

Well, presumably animals sleep a "perfect" amount because for them it's purely instinct. For humans, however, there are far more variables involved - we're not simply running on automated evolutionary instincts - which can be good if we take conscious advantage, but can also mean we can do things in a less than optimal way if we don't. Generally, I don't find that thinking of behavior from an evolutionary perspective to be particularly useful when it comes to humans.