Interleaving: A teacher's guide

Paul Main

Interleaving: A teacher's guide to using this study technique for better student memory and retrieval.

What is Interleaving?

Interleaving is a learning technique in which learners mix, or interleave multiple topics or subjects while studying to improve their learning process.

The theory proposes that for learning two or more related topics or concepts, it is better to alternate between them rather than focusing exclusively on one topic or concept at a time. For instance, if a student is learning about short-term difficulties of pollution in a geography project, the student would also study how to bring improvements in energy supply on the same day by mixing the two topics or by switching back and forth between them.

This study strategy has been linked to an improvement in memory and its popularity has grown as the beneficial effects have been documented by organisations such as the chartered college of teaching. Interleaving is a method of teaching where students learn concepts in different ways at different times. This approach helps them retain information better because they're not just memorizing facts and figures. They're actually thinking about the material and applying it to real life situations.

When you teach a concept through interleaving, you give students practice with the material before moving on to another topic. So when you teach a concept, you should spend some time explaining it, then move on to another concept. Then come back to the original concept later.

This process repeats itself throughout the course, giving students multiple chances to understand the material. Interleaving works well for topics that require deep understanding, such as algebra or calculus. But it doesn't work very well for subjects that are taught in bite-sized chunks, like reading comprehension or vocabulary.

To help students grasp these types of concepts, try interleaving during class time. Instead of lecturing on the same topic over and over again, break the lesson down into small pieces and let students discuss each piece individually. Afterward, bring the group together and review the entire concept.

Interleaving is an effective strategy for developing problem-solving and categorisation skills. Also, interleaving leads to enhanced long-term retention and increased ability to transmit learned knowledge.

Interleaving forces the deep brain stimulation for retrieving because each practice attempt is new, so rote responses used from short-term memory won’t help. Experts of Cognitive Psychology believe that interleaving improves the brain’s ability to discriminate or differentiate, between concepts and fortifies memory associations. Along with the application of spacing, schools are increasingly seeing this as an effective strategy for exam preparation. In this article, we will explore the implications for memory & cognition.

Interleaved practice vs massed practice
Interleaved practice vs massed practice

What does Research say about Interleaving?

Many research studies have indicated that students learn better when they are repeatedly exposed to different interleaved or shuffled concepts, rather than blocked (Rohrer, 2012). In a study session, a student might feel that he had a more difficult time studying due to interleaving. But, in the long-term, he would end up learning better through interleaving.

Cognitive psychologists suggest that one shouldn’t study a single topic, idea, or similar type of problem for too long. It is recommended to change the topic often. Interleaving may seem more difficult than studying a single topic for a long time, but it is more beneficial in the long run (Kornell & Bjork, 2013).

Bjork R & Bjork E (2011) assessed the impact of adding two desirable difficulties in making the task easier. In their study, Bjork R & Bjork E (2011) focused on a relatively short-duration set of tasks provided in a single lesson and assessed how desirable difficulties affect the learning process of a topic. Their study revealed that making things difficult in a positive manner, results in improved learning of the students. In another study conducted by Kornell & Bjork (2013), the researchers investigated whether interleaving can be used to improve the performance of students. The researchers compared three groups: Students who studied a single topic; students who studied two topics simultaneously; and students who studied two topics sequentially. They found that students who studied two topics concurrently performed significantly better than those who studied only one topic.

In another study, Rohrer (2012) examined the effect of interleaving on the performance of students. He found out that students who were taught using interleaving outperformed those who were taught using blocking.

The above mentioned studies provide evidence that interleaving helps in improving the overall performance of students. However, there is no conclusive proof that interleaving helps students retain information longer.

Desirable difficulties
desirable difficulties sketch note

What are some interleaving strategies?

There is no single correct way to use interleaving. Its effectiveness depends upon many factors such as learners' surrounding environment, the type of material involved, as well as learners' abilities and preferences. Hence, the learner needs to assess these factors and then decide when and how to interleave. It is also suggested to assess the effectiveness of the interleaved practice over time and experiment with multiple approaches to it.

To interleave during the study, learners should choose different topics and spread them all through their learning sessions. The concepts can be acquired from the same subjects or different subjects, but according to some experts of Educational Psychology, this strategy is most effective when the topics are related in some way. For instance, in a study session, a learner could devote some time to Clinical Practice of Psychology, some time to Applied Cognitive Psychology, some time to Experimental Psychology and then start a new cycle with the Clinical Practice of Psychology, possibly reviewing the topics in a different sequence and using multiple study strategies.

Shuffling things up enables learners to retrieve information and create new connections amongst the concepts: for instance, how is a specific concept of Experimental Psychology relates to what was studied in Applied Cognitive Psychology? It must be ensured that the student devotes sufficient time to each topic. Each time a topic is studied, a deeper understanding is achieved. Students must not use interleaving as an excuse to shift to another subject if the current subject comes to be too challenging. Instead, they must continue to study one topic until they have a sense of achievement before switching to another topic.

What does interleaving look like
what does interleaving look like

How is Interleaving different from Blocked Practice?

Interleaving, which can be sometimes called mixed practice or varied practise, is different from blocked practise (also known as specific practice), which involves paying attention to just one type of practice or topic at a time. Short-duration auditory memory traces may last only a few seconds, which makes it harder to memorise the phonological traits of an earlier item. Hence, due to the short duration of auditory memory traces, blocking practice is more likely to lead to better pronunciation learning as compared to interleaving when proficiency was evaluated by way of either a recall test (Experiment) or multiple-choice tests (Experiments).

The main reason why interleaving helps memory is that it makes the brain work harder. When you are trying to memorize something, your mind works hard to make sense of what you are trying to remember. This is called active encoding. Active encoding requires a lot of mental effort. If you are constantly changing the way you think about the same thing, then you are engaging in passive encoding. Passive encoding doesn’t require much mental energy.

When you are actively engaged in thinking about something, you are creating a neural network in your brain. This neural network is made up of neurons which are connected to other neurons. These connections help us store memories. When we are passively engaged in thinking about something we are not creating any new neural networks. We are just reusing old ones. This means that our brains don’t get as many opportunities to create new neural networks. As a result, our brains become less efficient at storing memories. This is where interleaving comes into play. By constantly switching between different ways of thinking about the same thing, you are creating more neural networks. This allows your brain to create more connections and therefore store more memories.


blocked vs interleaved practice
Blocked vs interleaved practice

What are the benefits of embedding interleaving in educational practice?

The benefits of using interleaving are attributed to Memory & Cognition. Interleaving is an effective learning strategy that includes retrieval practice. Therefore, it may seem harder than spaced practice. But, one must not forget that effortful studying may seem difficult but gives better results in long run. Benefits of interleaving may be seen in the conceptual learning of similar types of math problems (such as evaluating volumes of different shapes), similar categories of visual stimuli and confusing grammatical tenses.

In conclusion, if your students are studying for an exam, why would you choose to cram everything into one night instead of spreading it over several nights? Well, because when you spread it out like that, you have more time to review each section before going on to the next. This means you're able to retain information better and remember it longer. And since you're spending more time reviewing each section, you're also more likely to understand it fully.

Interleaving Strategies
Research results of interleaving

Following are the most significant benefits of using Interleaving in education:

  • Interleaving two tasks can enhance students' performance in both tasks as compared to practising each task separately, even when students spend an overall less time doing each task.
  • Interleaved practise is especially useful for studying something that relates to problem-solving - like physics or math- interleaving helps select the right strategy to solve a problem.
  • One significant mechanism that interleaving is regarded as being caused by, is contextual interference. An increased contextual interference, prompts students to use increased contrast between concepts and learning strategies, which helps students notice the similarities, differences and connections between concepts.
  • Examples of Interleaving, from distinct categories can enhance learners’ technical skills more than practising with the examples of the same category each time.
  • Interleaving different topics can help prevent the confusion that may arise from learning similar topics simultaneously.
  • Interleaving has been associated with other benefits in education, such as an improved ability to identify mistakes, as well as an enhanced ability to focus and set goals.
  • It is easy to implement interleaving because it mostly doesn’t require any special resources.

It can be said that interleaving offers a lot of help for the students in their learning process. These constructive effects make interleaving an effective learning strategy to be used by the students in a variety of situations.