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How quickly do students forget things?

How quickly do students forget things?

4 min read
  • The science of learning

The ability to recall and retain information is crucial to optimising students’ memory, knowledge and learning. But unfortunately, we all forget things at a much quicker rate than we would like (or indeed realise). This has huge implications for how we help teach students.

Let’s take a look at just how quickly students forget things, and the implications that this can have in the classroom…

What the research says

Researchers have been trying to answer this question for years, with some of the earliest research on this conducted in 1885. Early psychologist Ebbinghaus found that people forget information over time unless they revisit it. His forgetting curve suggested that students usually forget the majority of what they have learned within 24 hours. After that, forgetting continues but at a much slower rate.

In a more recent study, researchers investigated the rate at which students forget information. In a series of experiments, researchers tasked students to remember a list of sentences (some saw the sentences more than others). After seeing the sentences and then completing a distractor tasks, students were then asked to recall the sentences five minutes later. Students were then also asked to recall the sentences at different time points, such as the next day, three days later and 1 week later.

What the results showed

Overall, the research suggests that as time goes on, the amount they forget increases (this isn’t too much of a surprise).

After 1 week, students remembered the same amount of information regardless of how many times they read the sentences. The rate of forgetting was faster between 30 seconds and 24 hours, and slower between 24 hours and 1 week. This suggests that students forgot most of the information within the first 24 hours.

When students listened to sentences instead of reading them, they acquired the most information when they heard sentences six times, followed by four times, followed by twice. This effect was found up to 1 week after students read the sentences.

What this really means

The key points to take from this research are that:

  • The rate of forgetting was fastest within the first 24 hours of learning. Forgetting after 24 hours occurred at a much slower rate.
  • The amount of information acquired by students within the first 24 hours of learning depends on the number of times that information is repeated to them.
  • The rate of forgetting is not dependent on the amount of information students learn within the first 24 hours of learning.

The results of this research demonstrated that not only do students forget things very quickly after they learn them, but more importantly, that students tend to forget information no matter how much they initially seem to remember, regardless of how the information is presented to them.

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What can teachers do to combat these effects?

There are some strategies that you can use in order to prevent your students from forgetting what you have taught them over time. Here are some tips…

Teach your students how quickly they forget things

When they are aware of how quickly they forget things, your students are more likely to engage in independent revision of previously-learned information. Make sure you highlight to your students that no matter how well they seem to remember a piece of information when they first learn it, research shows that they will forget a large amount of that information within the first 24 hours of learning.

Encourage Retrieval Practice

Retrieval practice gets your students to generate answers to questions. Doing this will allow your students to practice recalling learned information, strengthen memory traces and increase the chances that the information that you are teaching them is transferred to their long-term memory. To do this, you can have short quizzes in your lessons, or encourage your students to complete past papers and produce flashcards.

Encourage Spacing

Spacing is a learning technique that requires students to spread out their study sessions over time so that they are studying learning material little and often. When students cram all of their revision in the few nights before the test, they are likely to forget most of what they have revised.

Encouraging your students to engage with the learning material regularly and well ahead of time increases the chances that the information is transferred to their long-term memory, and decreases the chances of forgetting.

Daily and weekly reviews

Barak Rosenshine highlighted the importance of reviewing learning at the start of each lesson in his first Principle of Instruction and weekly and monthly reviews in his tenth Principle of Instruction.

Reviewing what your students have learned last lesson ensures that information is well connected and embedded in their long-term memory, reducing the likelihood of forgetting.

Final thoughts

Overall, students tend to forget things pretty quickly – learning takes time and effort.

Most of the forgetting happens within the first 24 hours of learning, which is why implementing strategies like interleaving, spacing and daily reviews in your classroom are so important for supporting students’ learning, enhancing your students’ memories, and reducing the chances of forgetting.

About the editor

Bradley Busch

Bradley Busch

Bradley Busch is a Chartered Psychologist and a leading expert on illuminating Cognitive Science research in education. As Director at InnerDrive, his work focuses on translating complex psychological research in a way that is accessible and helpful. He has delivered thousands of workshops for educators and students, helping improve how they think, learn and perform. Bradley is also a prolific writer: he co-authored four books including Teaching & Learning Illuminated and The Science of Learning, as well as regularly featuring in publications such as The Guardian and The Telegraph.

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