Sleep is not time off for memory. While you sleep, the brain replays and strengthens what it practiced during the day. A large 2010 review by Susan Diekelmann and Jan Born gathered the evidence that sleep supports the consolidation of memories, the process that makes a new memory more stable.
Key idea
Get enough sleep while you are learning. A short review before bed and a quick check in the morning fit well with how sleep helps.
Worked example: Worked example
Which plan is better the night before a recitation?
- A: stay up past midnight practicing.
- B: one practice run after supper, a full night's sleep, and one run at breakfast.
- B keeps sleep and adds a morning check.
Answer: B.
Why it works
A memory is fragile at first. Sleep is one of the times it becomes sturdier, so trading sleep for more study often loses more than it gains.
Common mistake
Thinking you can learn something new while you sleep, by playing a recording. Sleep helps keep what you practiced while awake; it is not a way to learn new material.