Spaced repetition explained
Why reviewing at growing gaps beats rereading, and a simple way to start using it this week.
You study something, you understand it, and two weeks later it's gone. That's not a flaw in you. It's how memory works, and it's predictable enough to plan around.
The forgetting curve
In the 1880s the psychologist Hermann Ebbinghaus measured how fast he forgot lists he had learned. The pattern he found has held up ever since: we forget fast at first, then more slowly. Most of the loss happens in the first day or two.
The useful part is what happens when you review. Each time you successfully recall something, it fades more slowly than before. So the gap before the next review can be longer.
The idea in one line
Review just before you would forget, and make the gaps grow.
A typical schedule for one fact might look like this:
| Review | Gap after the last one |
|---|---|
| 1st | 1 day |
| 2nd | 3 days |
| 3rd | 1 week |
| 4th | 2–3 weeks |
| 5th | 1–2 months |
After a handful of reviews, totalling a few minutes, it's in long-term memory.
Why rereading doesn't work as well
Rereading feels productive because the material looks familiar. But recognising something isn't the same as recalling it, and in an exam you have to recall. Spaced repetition works because every review is a small test: you try to bring the answer back before you see it. That effort is what strengthens the memory.
Starting this week
- Turn what you learn into questions. One idea per card. "What's the time complexity of indexing an array?" beats "Arrays".
- Answer before you flip. Say or write the answer first.
- Be honest when you mark it. If you hesitated or got it partly wrong, mark it Again.
- Do a little every day. Ten minutes daily beats an hour on Sunday.
- Let wrong answers come back sooner and right ones later.
Doing this in StudyBuk
Today, StudyBuk writes flashcards for you from your pathway, and you practise them with Got it and Again. Cards you mark Again come first the next time you practise. See the flashcards guide.
Scheduled review (coming soon): StudyBuk works out which cards are due each day using the growing gaps above, and puts them on your Today list.