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Are Retrieval Practice and Interleaving stronger together?

Are Retrieval Practice and Interleaving stronger together?

4 min read
  • Retrieval Practice
  • Spacing & Interleaving

There are so many teaching strategies that you can use in the classroom. However, these strategies often don’t need to be done in isolation. The hope when combining strategies is that their benefits multiply.

Two popular strategies based on cognitive science research are retrieval practice and interleaving. So, does using both in combination actually help?

What is Retrieval Practice?

Retrieval practice is one of the most effective learning strategies and is the process of generating an answer to a question. By requiring students to recall previously-learnt knowledge, it helps them create stronger memory traces which increases the likelihood that the information will be transferred to their long-term memory. Some ways to use this technique include answering past papers and testing yourself on a flashcard.

Using retrieval practice has many benefits including:

  • Improving memory, retention and recall
  • Making students more confident learners
  • Reducing exam nerves
  • Helping identify what students do and don’t know

What is Interleaving?

Interleaving is the strategy of alternating the order of topics in a subject. This is opposed to blocking, which is fully covering a topic before moving on to the next.

Some benefits of using interleaving include:

  • Better academic performance – Research shows that students who used an interleaving revision session performed 7% better in their final exam, compared to those who revised using a blocked session.
  • Improving memory – Interleaving helps students make connections between topics, which strengthens memory associations. Research suggests that interleaving helps consolidate the information and results in better long-term retention.
  • Comparing and contrasting – It prompts students to focus on the subtle but important differences in the topic. This helps ingrain the differences in our memory.
  • Knowing which strategy to use – It helps students think about which strategy is the most effective to use. This means they think about the process in more detail.
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Combining Retrieval Practice with Interleaving

In a fascinating study, researchers found a simple way of using interleaving and retrieval practice in the classroom. To do this, they divided topics within a subject into three groups:

  • Blocked condition –These topics were tested using a blocked format.
  • Interleaving condition – These topics were tested using an interleaved format.
  • No test condition – These topics were only taught and not tested on.

For four weeks, students alternated between completing blocked quizzes or interleaved quizzes. One month later, students completed a test on a mix of topics that they were taught. The researchers found:

  • Benefits of Retrieval Practice – Students performed better on the topics that were in their weekly quiz.
  • Benefits of Interleaving – Students performed better on topics that were tested using an interleaved design compared to a blocked design.

Although this shows the benefits of using both retrieval practice and interleaving, it is important to note that students might have performed better simply because they found the topics in the interleaving condition easier than the topics in the blocked condition.

Despite this, there are many studies that suggest that using an interleaved design is better for learning than using a blocked design. For example, in another study, students who completed interleaved assignments did nearly twice as well as their peers who completed the blocked assignments.

The practical implications

One easy way to implement interleaving and retrieval practice into your lesson is to, instead of having end-of-topic quizzes, try and interleave other topics that could link together. This can help students learn and understand the topics better.

Also, don’t worry if immediately after using interleaving, students do worse on their test. This is often the case – but in the long term, interleaving is found to be much more effective than blocking.

Final thoughts

Although interleaving is an effective learning strategy, teachers often struggle to implement this into the classroom as it might be chaotic or could only be done when redesigning the curriculum. Researchers also found there was a link between spacing and Cognitive Load Theory.

One way you can overcome this is by implementing interleaving topics in weekly tests. Using this method is an easy way to ensure that you reap the benefits of two of the most effective learning strategies.

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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