Review new material within 24 hours of learning it

The forgetting curve is steepest in the first day — a brief review before sleep captures material when it is most at risk.

Why it works

Ebbinghaus’s data show that most forgetting from a single learning event occurs in the first 24 hours. A review within this window catches the material while a significant trace still exists and while sleep-based consolidation is about to occur. Even a brief 5-minute recall attempt re-encodes the material and resets the forgetting clock at a higher baseline, so the next review can be scheduled at a much longer interval.

How to do it

1. After any significant learning event (lecture, reading, coaching session), schedule a 5–10 minute review before the end of the day.
2. Do the review as retrieval, not rereading: close the material and write or say what you remember.
3. Focus on the points you struggle to recall — those are the ones that would have been lost by morning.
4. Do not re-read the full material; re-read only the specific gaps your recall attempt revealed.

Evidence

Ebbinghaus (1885/1913) documented the forgetting curve through rigorous self-experimentation with nonsense syllables. While his specific methodology has limitations, the general shape of the curve has been replicated with meaningful material across many subsequent studies. (observational)

Ebbinghaus used nonsense syllables; real-world decay for meaningful material with prior context is slower, but the qualitative shape of rapid early decay followed by slower loss applies broadly.

Sources

• Ebbinghaus, H. (1885/1913), Memory: A contribution to experimental psychology

Common mistake

Treating the initial study session as sufficient and scheduling the next review days later, when the material will have largely decayed — paying a full retrieval cost for material that a timely review would have kept accessible.