Dreams and memory

Dreams happen when brains are running like computers without a display or memory, just a processor only, no hard drive. Nothing is stored. The reason we can't remember much when we wake up is that the moment we open our eyes, it's like turning on the screen right at the moment of a power failure. Our last glimpse of what's on the screen of our dreaming mind is all we have before it crashes. Reality causes our brains to load everything into RAM, constantly swapping out old information to be replaced with new. Everything is in short term memory until it is swapped out or stored in a long term file. Perception is impossible without memory.

I read an article recently that posited the theory that time perception is related to memory formation. Your perception of the passage of time is directly related to the new-memory density of the time which passed. The older you are, the more you've been there, done that, so fewer things are recognized as new information requiring storage and retrieval.

Neuroscientist David Eagleman of Baylor College of Medicine says that when you recall your first kisses, early birthdays, your earliest summer vacations, they seem to be in slow motion? "I know when I look back on a childhood summer, it seems to have lasted forever," he says.

That's because when it's the "first", there are so many things to remember. The list of encoded memories is so dense, reading them back gives you a feeling that they must have taken forever. But that's an illusion. "It's a construction of the brain," says Eagleman. "The more memory you have of something, you think, 'Wow, that really took a long time!'

"Of course, you can see this in everyday life," says Eagleman, "when you drive to your new workplace for the first time and it seems to take a really long time to get there. But when you drive back and forth to your work every day after that, it takes no time at all, because you're not really writing it down anymore. There's nothing novel about it."