You don't form longterm memories while asleep; you lose the last few minutes before you drop off, as well. Short-term memories are held, but they don't get stored.

And the same applies while you're dreaming - nothing's getting recorded. You can pull it out of short-term right after you wake up, but that fades right out.

When you do remember dreams, it's because you remember remembering them while you were awake. If it was vivid enough to go over hard enough, then the second-hand memory gets stored.

[–] faintwhenfree@lemmus.org 17 points 10 months ago

Basically when you sleep only RAM works and no ROM storage is active, when you wake up ROM comes online, if you don't pull data from RAM fast, it will be overwritten by other things and you lose it forever.

[–] Buddahriffic@lemmy.world 6 points 10 months ago (2 children)

What about recurring dreams though? I've had some dreams where the most notable part was that it was a location that only existed in my dreams but I'd been there before in previous dreams. Wouldn't you need some kind of recollection to notice that?

[–] ConstantPain@lemmy.world 10 points 10 months ago

I had recurring dreams like that too, but I came to the conclusion that it was just my mind playing tricks and making me think that I had that dream before. It's like a dream deja vu.

[–] Nollij@sopuli.xyz 3 points 10 months ago

There's a few logical possibilities here.

#1 is that whatever stimuli produced it the first time keeps producing it later.

#2 is that you clearly did remember them enough, possibly when you woke up, to commit it to long term memory. This is a tautology, because you would have to remember it to know that it was in previous dreams.

#3, as someone mentioned below, is your mind playing tricks on you. Ever had a dream where you knew an object was something important and specific, even though its appearance in the dream was clearly not that? E.g. you know you're at your (specific) friend's house, but that's not at all what their house looks like. Dreams have a lot of weird substitutions like this, including the idea that you've been somewhere before