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What is the Forgetting Curve?

The human brain 'forgets' much of what we see and experience. If this didn’t happen, we would soon become overloaded with information and memories. However, this natural tendency to forget is unhelpful to learning, and trainers have to find ways to try and prevent it happening.

The human brain ‘forgets’ much of what we see and experience. If this didn’t happen, we would soon become overloaded with information and memories.

However, this natural tendency to forget is unhelpful to learning, and trainers have to find ways to try and prevent it happening.

The Forgetting Curve

The graph we saw in the video is known as the Forgetting Curve. Knowledge is represented by the red line and the slope shows how memory fades if it is not refreshed. The graph was established in 1886 and is just as relevant today¹. The steep drop of the line is a sobering reminder to trainers and learning designers of what can happen if something is only mentioned or shown once and never revisited.

Forgetting Curve, showing knowledge retention reducing almost to zero without any further practice or recall

When we experience something new, tiny electrical connections begin to grow in our brain. But if we don’t revise or refresh them, most simply wither away as shown below.

Steps of a neural connection that starts to grow and then withers. Has the word 'forgotten' above it

As soon as training moves from one aspect of a topic to another, the process of forgetting starts. How far it will progress is determined by the actions of both the trainer and the learner.

Working Against the Forgetting Curve

Some learners may revise the material after training of their own accord. But this cannot be relied upon with busy work schedules. So to ensure knowledge doesn’t fade, trainers get their learners to practice retrieval. This may involve a discussion, or a task which requires learners to apply a newly learned skill. It may include mini tests or quizzes. eLearning designers include quizzes and exercises in a module for the same reason.

An Illusion of Learning

Learners often think because they have understood something, that is sufficient to ensure it will be accessible in the future. But as we saw in Step 1.9 this may represent an ‘illusion of learning’. At school and college, assignments and examinations ensure that students refresh their learning. But in work-based learning, it’s often the responsibility of the trainer to prevent forgetting.

Forgetting Curve, showing impact on knowledge retention after each practiced retrieval session. Amount forgotten reduces with each visit

Each retrieval practice strengthens the ability to recall knowledge in the future. Just as a fitness instructor encourages their class to exercise, trainers encourage their learners to retrieve and thus strengthen new knowledge. If a learner can’t quite remember, the most helpful thing a trainer can do is encourage them to dig deeper into their memory (and resist the temptation to tell them). Knowledge that is coaxed back to the surface in this way becomes much more accessible.

Steps of growth of a neural connection which is retained, has the text 'remembered' above it

Trainers often need to be gently assertive when using retrieval practice. Learners may feel they have retained the information. As with activities, instead of asking whether learners would like to take a test or a quiz, the best approach is to explain it is part of the training.

¹The original experiment was recreated in 2015 and reported similar results.

Talking point

Have you ever thought you’d learned something adequately, only to discover later that you had forgotten it? What could you have done differently with hindsight?
Would any of your training benefit from the addition of retrieval practice? How might you include this?