I know evolution is governed by chance and it is random but does it make sense to “ruin” sleep if there’s light? I mean normally, outside, you never have pure darkness, there are the moon and stars even at night. In certain zones of the Earth we also have long periods of no sunshine and long periods of only sunshine.

I don’t know if my question is clear enough but I hope so.

Bonus question: are animals subject to the same contribution of light or lack of it to the quality of sleep?

  • givesomefucks@lemmy.worldEnglish
    0·
    6 months ago

    We didn’t…

    “Full darkness” isn’t even a real thing in nature. It’s hard to tell with light pollution, but even in the absolute middle of nowhere with no artificial lights, you’re going to be able to see fairly well. Even with no moon, starlight isn’t just an expression. And on a full moon it can be surprisingly “bright” if you’re just out there for a while.

    It’s not like climbing into a cupboard, shutting the door, and sealing all the cracks with duct tape.

    You may be used to needi g full darkness to sleep, but that’s a learned habit. I guarantee if there was nothing you could do, it wouldn’t take you long to adapt your “requirement” of total darkness.

    • linucs@lemmy.mlOPEnglish
      0·
      6 months ago

      I’m not talking about myself, melatonine, is synthesized by the body when it’s dark, light can reduce or stop the synthesis.

      • givesomefucks@lemmy.worldEnglish
        0·
        6 months ago

        Nope.

        It’s a very specific wavelength of light that inhibits it.

        https://en.m.wikipedia.org/wiki/Melatonin#Regulation

        That’s why there’s “blue light filters” on electronics these days. That wavelength isnt included with moonlight/starlight… maybe on a big full moon there’s be some.

        And why people prefer soft yellowish lights when relaxing and not the bright ass LEDs.

    • Contramuffin@lemmy.worldEnglish
      0·
      6 months ago

      This is untrue - we have explicitly evolved to sleep in the dark. Sleeping in the light is a learned behavior that’s more or less an exploitation of a loophole in the circadian clock

      • givesomefucks@lemmy.worldEnglish
        0·
        6 months ago

        …

        A specific wavelength may effect you…

        That wavelength is not present in moonlight/starlight, which is not “full darkness”.

        For the vast majority of human evolution, “full darkness” wasn’t safe, and wasn’t even really possible.

        I understand what you and OP are trying to say. And you both kind of have the general idea but none of the details.

        Like how you got taught basic things in 6th grade, but by 12 grade you’re learning what you thought was the whole truth, was just a general overview.

        Which wouldn’t be bad if you recognized it, but loads of people want to insist the short summary the learned as a child is as deep as it gets

        • Contramuffin@lemmy.worldEnglish
          0·
          6 months ago

          Oh trust me, I know way more than you think. It is literally my job to study circadian rhythms. I can very comfortably say that you’re wrong

          • givesomefucks@lemmy.worldEnglish
            0·
            6 months ago

            The intensity and the wavelength of light influence entrainment.[2] Dim light can affect entrainment relative to darkness.[15] Brighter light is more effective than dim light.[12] In humans, a lower intensity short wavelength (blue/violet) light appears to be equally effective as a higher intensity of white light.[11]

            https://en.m.wikipedia.org/wiki/Light_effects_on_circadian_rhythm

            For anyone else, I won’t try to change your mind.