Spaced repetition when you repeatedly review what you’re learning at increasingly spaced-out intervals.
The brain needs lots of energy to function properly.
One energy conservation tactic the brain employs is forgetting. The less your brain has to hold in short-term memory, the fewer resources it has to use.
This means your brain is constantly forgetting on purpose. And while this is good for healthy brain function, it’s not all that helpful when you’re trying to learn something.
One way to visualize this process is through the Ebbinghaus Forgetting Curve:
The red curve on the chart above represents your remembering ability for a new concept or idea. With each day that passes after your initial learning (see the days at the bottom of the chart), your ability to remember it diminishes rapidly.
The green curves represent your remembering ability with additional reviews. With each day you review a concept or idea, your ability to remember it is enhanced, illustrated by the curves getting flatter.
Forced retrieval works to counteract the forgetting curve through strategically spaced-out reviews. After your initial learning of a concept or idea, you might review it again the next day and maybe a few days after that. Then, as it gets easier to remember it, you start to “space out” the amount of time between reviews. Just as the forgetting curve starts to steepen, you surprise your brain with another forced review.
This might look like reviewing after a single day, then three days, then seven days, then ten days, so on and so forth, until you can go several weeks or months between reviews without it being difficult to remember.
The easiest way to use spaced repetition is using the notecard method.
While you might prefer to create physical notecards, the free app Anki is a powerful tool that combines digital notecards with an internal spacing algorithm. It’s the go-to study tool for medical students and learners in high-stakes programs.
Anki lets you create different kinds of notecards for whatever material you’re trying to memorize.
Each day, Anki will create study sessions for you. Each study session will present you with one side of a notecard and force you to remember what’s on the other side. After you recall the material, you rate how easy it was to remember (or if you weren’t able to remember it). Anki will then automatically show you that card again at some point in the future based on how you rated it.