Interleaving: A teacher's guide

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What Is Interleaving in Education?

Interleaving is a learning technique where students mix multiple topics or subjects during study sessions rather than focusing on one topic at a time. For example, instead of spending an entire period on fractions, a teacher might alternate between fractions, decimals, and percentages within the same lesson. This approach strengthens long-term retention and improves students' ability to distinguish between different problem types.

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.

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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 spaced practice, schools are increasingly seeing this as an effective strategy for exam preparation. The implications for memory & cognition.

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Why Does Interleaving Work Better Than Blocked Practice?

Research shows interleaving works because it forces students to constantly retrieve and apply different strategies, strengthening neural pathways. Studies by organisations like the Chartered College of Teaching demonstrate that while blocked practice feels easier and shows immediate gains, interleaved practice leads to superior long-term retention and transfer of knowledge. The difficulty students experience during interleaving actually signals deeper learning is occurring.

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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).

Students with sen may require additional support when implementing interleaving strategies, as maintaining attention across multiple topics can be challenging. Bjork R & Bjork E (2011) assessed the impact of adding twotopics can be challenging. Bjork R & Bjork E (2011) assessed the impact of adding two or more concepts together, to see if that could lead to improved learning outcomes. In their study, they found that interleaving can improve learning outcomes, especially when the concepts are related to each other.

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Practical Strategies for Implementing Interleaving

To effectively use interleaving in the classroom, consider these strategies:

1. Mix it Up: When planning lessons, intentionally alternate between related topics. For example, in a maths lesson, switch between algebra and geometry problems.
2. Review Sessions: During revision, avoid dedicating entire sessions to a single subject. Instead, create mixed practice sets that require students to switch between different types of questions.
3. Problem-Solving Variety: Present a variety of problem types, even if they seem unrelated at first glance. Encourage students to identify the underlying principles and apply the appropriate strategies.
4. Real-World Connections: Show how different subjects or concepts connect to real-world situations. This helps students see the relevance of what they're learning and improves retention.
5. Regular Assessments: Use regular quizzes or tests that cover a range of topics. This reinforces the need for students to retrieve information from different areas and strengthens their understanding.

By incorporating interleaving into your teaching practices, you encourage students to actively engage with the material, make connections between different concepts, and develop a deeper, more durable understanding.

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How Do You Design Interleaved Practice Sets?

Effective interleaved practice requires careful planning to maximise the discriminative contrast mechanism - the brain's ability to distinguish between different problem types when they're presented together. Start by selecting 2-3 related concepts that students often confuse, such as area, perimeter, and volume in mathematics, or metaphors, similes, and personification in English. The key is choosing topics that share surface similarities but require different solution strategies.

Structure your practice sessions using 10-15 minute cycles where you rotate between concepts rather than spending entire lessons on single topics. For example, in a 45-minute maths lesson, spend 15 minutes on solving equations, switch to interpreting graphs for 15 minutes, then move to probability problems. Within each segment, present 3-4 problems before switching. This timing prevents cognitive overload whilst ensuring students experience enough examples to recognise patterns and differences between problem types.

When designing mixed practice homework, create worksheets that randomly distribute different question types rather than grouping them by concept. Include a brief recap section where students must identify which strategy to use before solving. For instance, a science homework might include questions on photosynthesis, respiration, and transpiration mixed throughout the worksheet, forcing students to actively decide which biological process each question addresses rather than simply following a repetitive pattern.

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Why Does Interleaving Feel Harder for Students?

Interleaving creates significant challenges for working memory because students must constantly switch between different cognitive strategies and hold multiple problem-solving approaches in their minds simultaneously. Unlike blocked practice, where students can rely on recent examples and maintain the same mental approach, interleaving forces the brain to actively retrieve and apply different strategies for each new problem. This creates interference effects that make learning feel more difficult and less fluent, even though it actually strengthens long-term retention.

Students often report feeling less confident about their learning during interleaved practice because they make more mistakes and need to think harder about each problem. Teacher Shannon Payette observed that her pupils initially complained when she introduced mixed practice sessions, saying they felt 'confused' and preferred working through similar problems in sequence. This reaction occurs because interleaved practice prevents students from falling into automatic routines, forcing them to engage in deeper processing and actively discriminate between different problem types.

The perceived difficulty stems from what researchers call the difficulty paradox - whilst blocked practice feels easier and creates an illusion of learning, interleaved practice requires more mental effort but produces superior long-term results. Students need explicit explanation about why this approach feels challenging. Teacher Kim Kelly found success by explaining to her Year 8 students that 'feeling confused means your brain is working harder to make stronger connections', helping them understand that the temporary discomfort signals effective learning rather than poor teaching or their own inadequacy.

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What Are Common Pitfalls When Implementing Interleaving?

The most frequent mistake teachers make is attempting to interleave too many concepts simultaneously, overwhelming students' cognitive capacity and creating frustration rather than productive challenge. Beginning teachers often try to mix 4-5 different topics in a single lesson, which exceeds working memory limits and prevents students from recognising meaningful patterns. Start with just 2 concepts, gradually building to 3 once students adapt to the switching demands. Similarly, avoid interleaving completely unrelated topics - the concepts should share enough similarity that students might reasonably confuse them, but require distinctly different approaches.

Another critical error involves insufficient scaffolding when introducing interleaved practice. Some teachers jump directly from blocked practice to fully mixed sessions without providing intermediate support. Successful implementation requires a gradual transition: begin with short interleaved segments within predominantly blocked lessons, explicitly model the decision-making process for choosing strategies, and provide students with strategy cards or decision trees until they internalise the discrimination process. Teacher observations show that students need at least 3-4 guided practice sessions before attempting independent interleaved work.

Many educators also fail to maintain the crucial balance between challenge and overwhelm. Whilst interleaving should feel more difficult than blocked practice, students experiencing genuine distress or complete confusion require additional support. Monitor student responses carefully - productive difficulty involves increased effort and occasional mistakes, but students should still achieve reasonable success rates. If accuracy drops below 60-70%, consider reducing the number of interleaved concepts, providing additional worked examples, or temporarily returning to blocked practice before reintroducing mixed formats. Remember that interleaving works best when students have already achieved basic competency in each individual concept through initial blocked practice.

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Classroom Application: Putting Interleaving into Practice

These practical steps show teachers how to implement interleaving effectively across different subjects and year groups.

1. Plan mixed topic sequences: Instead of teaching fractions for three consecutive lessons, alternate between fractions, decimals, and percentages within each 60-minute session. Spend 15-20 minutes on each topic, then cycle back through them.
2. Create interleaved worksheets: Design practice sheets that mix problem types rather than grouping similar questions together. For KS3 maths, include algebra, geometry, and statistics problems randomly distributed across the same worksheet.
3. Use rotation stations: Set up three learning stations covering related topics. In KS2 science, create stations for solids, liquids, and gases. Students spend 10 minutes at each station, rotating twice through all three during the lesson.
4. Implement retrieval spirals: Begin each lesson by asking students to solve problems from three different previous topics. Say "Before we start today, solve this equation, identify this shape, and calculate this percentage from our recent learning."
5. Design homework schedules: Replace subject-specific homework blocks with mixed practice. Instead of "Monday: all history, Tuesday: all geography," assign tasks like "Monday: Roman Britain timeline, coastal erosion diagram, and fraction calculations."
6. Apply quick-fire reviews: During KS4 revision periods, spend 5 minutes on topic A, 5 minutes on topic B, 5 minutes on topic C, then repeat. This prevents students from settling into single-topic comfort zones.
7. Structure assessment preparation: Three weeks before exams, create revision timetables that revisit topics in 20-minute blocks rather than dedicating entire sessions to single subjects.

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Classroom Example

In a Year 8 English lesson, Mrs. Thompson alternates between persuasive writing techniques, grammar revision, and poetry analysis every 15 minutes. Students initially feel confused switching between metaphors, semicolons, and persuasive language, but by half-term, they demonstrate stronger retention and can identify these elements more accurately in unseen texts compared to her previous classes who studied each topic in separate week-long blocks.

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15 Interleaving Activities for Every Subject Area

These evidence-based interleaving strategies help students develop stronger discrimination skills and more durable learning. Implement these interleaved practice activities to combat the illusion of competence created by blocked practice.

1. Mixed Maths Problem Sets: Instead of 20 identical fraction problems, create worksheets mixing fractions, decimals, percentages, and ratios. Students must identify the problem type before selecting the appropriate strategy, building crucial discrimination skills.
2. Shuffled Vocabulary Practice: When reviewing vocabulary, mix words from multiple units rather than drilling current terms only. Interleaving vocabulary from different topics forces deeper processing and improves long-term word retention.
3. Genre-Mixed Reading Comprehension: Assign reading passages that alternate between narrative, persuasive, and informational texts within the same session. Students practise identifying text features and applying appropriate comprehension strategies.
4. Interleaved Science Concept Questions: Create revision quizzes mixing questions from different topics - photosynthesis alongside forces alongside cells. Students must retrieve relevant knowledge and avoid confusion between similar concepts.
5. History Source Analysis Rotation: Present primary sources from different time periods in mixed sequence. Students practise contextualising evidence and identifying era-specific characteristics through discrimination rather than memorisation.
6. Grammar Practice with Mixed Rules: Combine exercises on commas, semicolons, apostrophes, and capitalisation within single worksheets. Students must identify which rule applies rather than mindlessly applying the same pattern.
7. Art Technique Stations: Set up studio rotations where students move between shading, colour mixing, and perspective drawing within one session rather than spending entire lessons on single techniques.
8. Sports Skill Circuits: Design PE lessons mixing passing, shooting, and defending drills rather than blocking entire sessions on one skill. Athletes develop better game-like decision-making through interleaved practice.
9. Music Theory Interleaving: Mix sight-reading, rhythm dictation, and chord identification exercises rather than drilling each skill separately. Musicians build flexible musicianship through varied practice.
10. Foreign Language Grammar Mixing: Combine verb tense practice across present, past, and future forms within single exercises. Students strengthen their ability to select appropriate tenses in authentic communication.
11. Cumulative Homework Design: Structure homework assignments with 60% new content and 40% review from previous weeks, rotating the review content regularly. This built-in interleaving reinforces long-term retention.
12. Exit Ticket Interleaving: Include one question from today's learning and two from previous topics on every exit ticket. Track responses to identify both current understanding and retention gaps.
13. Problem-Type Identification Tasks: Before solving problems, have students categorise them by type and required strategy. This metacognitive interleaving activity builds discrimination skills essential for exam success.
14. Spiralled Unit Assessments: Design end-of-unit tests including questions from all previous units, not just current content. Cumulative assessment provides natural interleaving opportunities whilst combating forgetting.
15. Daily Starter Rotation: Rotate starter activities through different topics each day. Monday reviews last week's content, Tuesday covers material from two weeks ago, Wednesday addresses the previous month, creating systematic interleaving.

Start implementing interleaving gradually by mixing just two or three topics initially. Explain to students why practice feels harder but produces better results - understanding the science helps them persist through the desirable difficulty of interleaved practice.

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Frequently Asked Questions

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Conclusion

Interleaving presents a powerful alternative to traditional blocked practice, developing enhanced long-term retention and problem-solving capabilities. While it may initially pose a greater challenge to students, this very difficulty is a catalyst for deeper cognitive processing and stronger memory formation. By strategically mixing related topics and encouraging students to discriminate between different concepts, teachers can develop a more effective and enduring learning experience.

Embracing interleaving requires a shift in mindset, both for educators and learners. It necessitates a move away from the comfort of concentrated study blocks towards a more dynamic and interconnected approach. As research continues to validate the benefits of interleaving, its integration into educational settings promises to equip students with the skills and knowledge necessary to thrive in an increasingly complex world. The ability to connect disparate ideas, apply knowledge flexibly, and retain information over time are invaluable assets that interleaving helps to cultivate.

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Further Reading

Interleaved practice research

Spacing and interleaving effects

Mixed practice benefits

• Bjork, R. A., & Bjork, E. L. (2011). Making things hard on yourself, but in a good way: Creating desirable difficulties to enhance learning. In M. A. McDaniel, & R. F. Pohl (Eds.), Applied research on memory and cognition (pp. 5-30). Psychology Press.
• Kornell, N., & Bjork, R. A. (2008). Learning concepts and categories: Is spacing the “enemy of induction”? Psychological Science, 19(6), 585-592.
• Rohrer, D. (2012). Interleaving helps students distinguish among similar concepts. Educational Psychology Review, 24(3), 355-367.
• Taylor, K., & Rohrer, D. (2010). The effects of interleaved practice. Applied Cognitive Psychology, 24(6), 837-848.
• Yan, V. X., Bjork, E. L., & Bjork, R. A. (2016). Integrating desirable difficulties to improve learning and retention: A global review. Educational Psychology Review, 28(4), 643-682.