Created:
24/7/2026
Last updated:
4/8/2026

What is the forgetting curve?

The forgetting curve describes how quickly we lose new information when we make no effort to retain it. First mapped by Hermann Ebbinghaus in the 1880s, the curve shows that memory fades fastest right after learning and then levels off. Repetition at the right moments flattens the curve and keeps knowledge usable.

The science behind the forgetting curve

Hermann Ebbinghaus tested his own memory of nonsense syllables and plotted how much he retained over hours, days and weeks. The pattern was clear: the steepest loss happens shortly after learning, and what survives the first days tends to last much longer. Later research has repeated the experiment with similar results, even though the exact shape of the curve varies with the material, the learner and how meaningful the content feels.

Two factors slow the decline. Meaning helps: we hold on to information we understand and connect to things we already know. Repetition helps even more: every well-timed review resets the curve at a higher level, which is exactly the mechanism behind spaced repetition.

The forgetting curve in practice for L&D teams

For workplace learning the curve carries an uncomfortable message: a single training session, however good, is mostly a temporary boost. What you can do about it:

  • Plan reinforcement into every course from the start, not as an afterthought.
  • Send short microlearning recaps in the days and weeks after a session.
  • Use quizzes that make participants retrieve knowledge, since active recall slows forgetting more than rereading.
  • Track knowledge over time in your LMS instead of measuring only completion.

Treat the curve as a design constraint rather than bad news. When you know knowledge fades on a schedule, you can schedule your training to meet it.

FAQ: the forgetting curve

How quickly do employees forget training content?

Faster than most training plans assume. Memory research since Ebbinghaus shows the same pattern: the steepest loss happens within the first days after learning, then the decline levels off. How much survives depends on how meaningful the content is and whether it gets used. The practical takeaway is about timing: reinforcement in the first week after training protects far more knowledge than a refresher months later.

Can you stop forgetting completely?

No, and that is not the goal. Forgetting is how the brain clears space for what matters, so some decline after every course is inevitable. What you can control is what survives. Content that gets used, repeated and connected to real work settles into long-term memory. Instead of chasing perfect retention, design training around the few things people truly must remember, and reinforce those deliberately.

What role does active recall play against the forgetting curve?

Active recall means retrieving knowledge from memory, for example through a quiz, instead of rereading it. Each successful retrieval strengthens the memory more than passive review does, which makes it one of the most effective ways to flatten the forgetting curve. In workplace learning this is a small design choice with a large effect: end modules with questions rather than summaries, and let participants practice remembering.

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