The forgetting curve, and how we fight it
Why your class forgets most of a lesson within a week — and what to do about it.
The learn-co.de team
20 June 2026
5 min read
More than a century ago, a German psychologist named Hermann Ebbinghaus sat down to memorise long lists of nonsense syllables — things like "WID" and "ZOF" — and then tested himself, again and again, to see how much had slipped away. What he found has been replicated more times than almost anything in psychology: we forget fast, and then we keep forgetting.
Plot how much you remember against the time since you learned it, and you get a curve that drops off a cliff in the first day or two before flattening into a long, shallow tail. By the end of the week, most of a one-off lesson is simply gone. Not misfiled, not hazy — gone.
The good news hiding inside that gloomy graph is the second half of Ebbinghaus's work. Every time you revisit a memory just as it's beginning to fade, the curve resets higher and falls more slowly. Review at the right moments and the same fact that vanished in a week can last a month, then a term, then…
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