Spaced repetition
Reviewing something at widening intervals, right as you're about to forget it — the most efficient way known to move a fact into long-term memory.
Memory fades on a curve. Hermann Ebbinghaus measured it in the 1880s by memorising nonsense syllables on himself: forgetting is steep at first, then levels off, and each time you successfully recall something the curve gets flatter — the memory decays more slowly than before.
Spaced repetition turns that curve into a schedule. Instead of cramming (which fights the curve and loses), you review a fact at expanding intervals — a day, then three, then a week, then a month — each review timed for the moment just before you’d have forgotten. Two effects compound:
- The spacing effect. The same total study time, spread out, produces far more durable memory than the same time massed together.
- The testing effect. Retrieving a fact strengthens it much more than re-reading does. The struggle to recall is the part that works.
This is why Evergreen notes are titled as claims rather than topics. A note called “Spacing beats cramming for durable memory” is a tiny self-test every time you meet it — you can try to reconstruct the argument before you read on. A note called “memory stuff” asks nothing of you and teaches nothing back. Phrasing a note well is, sneakily, scheduling a review you’ll do every time you stumble across it.