Sleep, Memory, and the Brain

We all know we do better when we're well-rested than when we're not. Modern sleep research has started to uncover exactly why that's the case. In terms of memory, there are at least two important reasons to make sure you're getting enough sleep.

First, we better remember what we learned the day before. This is because sleep plays an essential role in the conversion of short-term memory to long-term memory. Short-term memory relies heavily on a brain region known as the hippocampus (named after the Greek word for seahorse, given its shape), while long-term memory relies on a broad network of cortical association areas. When we learn new information, the hippocampus is very active, and when we sleep, it turns out that the activity of our hippocampus predicts how well we will remember what we learned when we wake up. Researchers have even found interesting ways to manipulate and improve this process. For example, in one study, experimenters paired the scent of a rose with a spatial memory task. When the study's participants slept, some of them were again exposed to the same rose scent. Relative to participants in a control condition, they experienced greater activation in the hippocampus during sleep, and performed better on the recall test when they woke up. The same pattern held for auditory stimuli. (I like to listen to something I don't ordinarily listen to while I'm studying (e.g. a recording of ocean waves or of fireside noises), and then let it play again while I sleep.) While we sleep, the hippocampus actively works with the relevant cortical association areas to transfer what we learned, so that when we wake up, not only is our memory improved, but our hippocampus is also freed to encode new memories.

Which brings us to the second reason sleep is so important to memory: it prepares our brains for learning the following day. We need our hippocampus to encode new memories. When we're sleep deprived, it doesn't work properly. You can read more about the specific studies in this paper, but the general gist is this: "Taken together, this collection of findings indicates that sleep disruption as well as total sleep deprivation prior to learning compromises the function of the human hippocampus to effectively commit new human experiences to memory." Unfortunately, it seems that not even caffeine can overcome these impairments!

So when you're working hard to learn something new, make sure you get enough sleep! Obviously you'll feel better, but perhaps more importantly, you'll do better. (I encourage you to check out the full paper. I've highlighted some of the parts I think are most interesting!)


This is so true.  Twice this has happen to me and it cost me a job, because the job had required technical test and another on my college tests.


Peter A.

Harvard PhD Student | Expert SAT, ACT, & GRE Tutor

900+ hours
if (isMyPost) { }