The Ebbinghaus forgetting curve: what it is and how to beat it in training

On Monday, your team completes a well-rated training session. By Friday, ask them what they remember and the answers are likely to be vague. That isn't a lack of commitment, and it isn't the trainer's fault. It is how memory works, and a German psychologist measured it more than a century ago.

Hermann Ebbinghaus's forgetting curve describes how quickly we lose what we have just learned. For anyone responsible for training, it raises an uncomfortable question: what is the point of investing in a programme if most of it fades within days? The good news is that Ebbinghaus also showed how to slow that forgetting down.

What is the forgetting curve?

The forgetting curve shows how the amount we remember of new information declines over time when we don't revisit it. It drops very steeply in the hours and days after learning, then levels off: whatever survives the first few days tends to last much longer.

Ebbinghaus's experiment

Hermann Ebbinghaus (1850–1909) published his findings in 1885 in Über das Gedächtnis (On Memory), one of the first experimental studies of human memory. His only test subject was himself.

To stop meaning from skewing the results, he memorised lists of nonsense syllables, each made up of a consonant, a vowel and a consonant. He then relearned the lists after increasingly long intervals and measured how much time he saved compared with learning them the first time. That saving became his measure of how much his memory had retained.

The result became famous. Most forgetting happens very early: after one day, he kept only around a third of the original saving, and after a month, around a fifth. In 2015, researchers Jaap Murre and Joeri Dros repeated the experiment and found a curve remarkably close to the original.

Does the forgetting curve apply at work?

Yes, with an important caveat. Ebbinghaus's syllables meant nothing, which is exactly why his numbers shouldn't be applied literally to workplace training. People forget meaningful information much more slowly, especially when it connects to what they already know and when they use it. The shape of the curve, however, holds for almost every kind of learning: a steep drop at the start, followed by a plateau.

So the lesson for training isn't a precise percentage. It is that the critical window is the days immediately after a session, and that is where action makes the biggest difference.

Six ways to beat the forgetting curve in training

1. Space out the review

After the curve itself, this was Ebbinghaus's most important discovery: spreading practice over time works far better than cramming it into one sitting. Each well-timed review flattens the curve, and the gap before the next one can grow each time. In practice, a short recap the next day, another a few days later and a final one a few weeks on will do more than an extra day of training.

2. Make people recall, not reread

Rereading notes feels productive but does little for memory. What makes learning stick is the effort of retrieving it: answering a question, solving a case or explaining an idea without looking. Psychologists Henry Roediger and Jeffrey Karpicke showed in 2006 that practising retrieval leads to better long-term retention than studying the material again.

3. Break content into short pieces

Short modules focused on a single idea lend themselves naturally to spaced review and fit more easily into a working day. That is one of the real strengths of microlearning, as long as "short" doesn't become "shallow": every piece needs a clear objective.

4. Connect it to real experience

We remember what we can attach to something we have lived through or a problem we actually face. Starting from real work situations and drawing on participants' own experience, as andragogy recommends, improves memory as much as motivation.

5. Put it into practice quickly

A skill used in the days after training resists forgetting far better than one left on the shelf. Plan a practical exercise or an on-the-job goal for the following week, and involve line managers in following it up. This is the logic of Kolb's experiential learning cycle: experience and reflection embed what theory alone doesn't.

6. Mix formats

A programme that combines group sessions, short online modules and regular reminders creates many more chances to come back to what was learned than a single event ever could.

What the forgetting curve changes for L&D teams

The forgetting curve should change how training is measured. An assessment at the end of a session mostly measures short-term memory. To know what really sticks, you need to assess weeks later and check whether behaviour has changed on the job. Our article on measuring the impact of training programmes covers the indicators HR teams use, and our whitepaper on the Kirkpatrick method explains how to evaluate training at every level.

It should also change how the budget is spent. Rather than making a session longer, it is often better value to invest in reminders and practice in the weeks that follow.

Learning by doing: why practice beats forgetting

Simulations bring together several of the levers that slow forgetting down. Participants actively retrieve what they know to make decisions, apply it in a realistic situation and can replay a scenario days later to reinforce it. We explain the approach in our guide to training simulations and in our game-based learning examples.

Our catalogue includes more than 70 video games built on this principle, available in up to 20 languages. Book your demo to see how they work.

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