Research is showing that “neuronal representations of memories are reactivated during sleep, as if the brain were replaying a recording”. Long-term memory storage requires this process, moving the important stuff out of your short term memory to your long term memory.
But how does the brain decide what to keep?
A study, published in the Journal of Neuroscience, asked several subjects to learn 40 new words. Some subjects were told they would be tested and others were told they’d be tested in 10 hours. Of the subjects that weren’t told, it didn’t really matter if they slept or not — they recalled the words just as well. The subjects who were informed of the test, however, managed to recall more words after sleeping.
Our results show that memory consolidation during sleep indeed involves a basic selection process that determines which of the many pieces of the day’s information are sent to long-term storage. Our findings also indicate that information relevant for future demands is selected foremost for storage.
Looking at this study also makes me wonder if the ties of memory have something to do with emotion. When you know you’re going to be tested, you worry about performing well. That anxiety isn’t just an arbitrary thing, but a chemical reaction in your body. While the study doesn’t touch upon emotion, I’m inclined to think that it’s an important marker of memory and would be curious to know how it affects memory storage during sleep.
For more information on how your long-term memory works during sleep, check out the full article over at Psychology Today.
Sleep Helps Us Remember What We Need [Psychology Today]