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The dos and don'ts of Interleaving

The dos and don’ts of Interleaving

4 min read
  • Spacing & Interleaving

Interleaving has the potential to be a very effective learning strategy. It is built around the concept that instead of studying each topic or concept within a subject one after the other, interleaving focuses on mixing them up.

Research shows that there are many benefits to using this strategy, with one such study finding that students who use this technique performed 7% better in their final exams than their peers. Interleaving has also been found to help consolidate the information learnt, leading to improved long-term retention.

However, out of all the areas of cognitive science, interleaving is the one that many report having the most challenges with. It can be tricky to implement, which can result in sub-optimal learning. We have therefore decided to take a look at some of the common traps surrounding interleaving and explore how to use it most effectively…

What is Interleaving?

Interleaving is switching between topics in a subject whilst studying. This is the opposite of blocking, where a student studies one topic in full before moving on to the next.

Some benefits to using interleaving include:

  • Improved academic performance ­– Those who interleave their revision perform better than their peers who block their learning.
  • Improved memory – Interleaving helps students make connections between topics, which strengthens their memory associations. This helps them consolidate the information and leads to better long-term retention.
  • Comparing and contrasting – Students are prompted to focus on the differences in a topic which helps them ingrain the information into their memory.
  • Knowing which strategy to use –Using interleaving helps students process the information in more detail, which helps them know the most effective strategy to use.

Do’s and don’ts of interleaving

Dos and Don’ts of Interleaving

Don’t: Interleave subjects instead of topics 

A common mistake is mixing up subjects when interleaving. For example, they will revise Maths, followed by English and Science all in one session.

Although this could be useful when revising (as it involves an element of spacing), it is not interleaving. Interleaving involves mixing up topics, not subjects. This allows students to find similarities and differences between the topics, as well as make connections. Mixing up topics helps form stronger connections and maximises the likelihood that the information is remembered.

Don’t: Interleave too many topics 

In a previous study, students who interleaved their homework tasks rated it as more difficult than those who blocked their tasks. They also thought they performed worse on these tasks, even though the opposite was true – those with interleaved homework remembered and performed better.

Therefore, students often find it difficult to use interleaving, even if it is better for them. Trying to interleave a lot of topics at the same time can make this even harder. This can result in students feeling frustrated and developing a cognitive overload, which may lead them to forget everything they studied. Therefore, when it comes to interleaving, less is definitely more.

Research hasn’t found a definitive answer to how many topics to interleave. Generally, in the research, we typically see about 3 different topics or concepts interleaved, so maybe this gives us an indication or a guideline to follow.

Don’t: Leave too long between Interleaving sessions 

One of the key benefits of interleaving is making connections between each topic. If topics are studied within a similar period of time, it encourages students to directly compare and contrastthem. However, leaving large gaps between each session can prevent this from happening.

Another problem that arises when having long gaps, is that too much forgetting occurs. Although some forgetting allows students to strengthen their memory connections, having too long of a gap can be frustrating for them, as they need to relearn all the information.

Do: Master the basics first

As mentioned before, interleaving is difficult. If students try interleaving a new topic with another one, this can only cause frustration and confusion. It can get overwhelming and make it even harder for them.

Therefore, interleaving should be used when students have already developed the fundamentals, by using blocking. Then, as students become more confident in the topics, they can build on the strong foundation they formed and start to interleave the topics.

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The best way to interleave your work  

So, what do all these strategies look like together?

Well, the best way to interleave your work after mastering the basics, is choosing a few related topics. There should be some similarity between the topics, but also not have too many topics which makes it difficult for students.

The gaps between each interleaving session should also be consistent and not too long. Doing this helps implement the benefits of spacing out learning, and result in students remembering more information.

Final thoughts

Interleaving is very beneficial for students learning. It can improve their academic performance, memory and help them know what strategy to use when in exam conditions. However, there are some common mistakes that students might make when it comes to using this technique.

Often students might interleave different subjects, include too many topics or leave large gaps between each session. By mastering the basics first, choosing a few related topics and leaving consistent gaps between sessions it can allows students to gain the most from this effective strategy.

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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