Tired of Forgetting What You Just Studied?

You spend hours cramming for an exam. You master one topic, then the next, feeling confident. But a week later, it’s all a blur. When faced with a mixed-problem test, you freeze, struggling to remember which formula or concept to apply. If this sounds familiar, you’re not alone. The problem isn’t your effort; it’s your method.

Most students use a technique called “blocked practice”—studying one topic intensively before moving on. While it feels productive in the short term, it’s a major reason why knowledge fades so quickly. It’s time to upgrade your study OS with a powerful, science-backed technique: interleaving.

Interleaving is the simple practice of mixing up different but related topics during a single study session. Instead of drilling one concept over and over, you switch between several. This small change forces your brain to work harder to retrieve information, building stronger, more flexible neural pathways. The result? Deeper understanding and dramatically improved long-term memory.

What Is Interleaving and Why Does It Work?

To understand interleaving, let's first look at its opposite, the method most of us use by default.

  • Blocked Practice: Imagine you’re learning to identify the works of famous painters. With blocked practice, you would study 20 Monet paintings, then 20 Picasso paintings, and finally 20 van Gogh paintings. It’s predictable and feels easy.
  • Interleaving: With interleaving, you would study a shuffled deck of 60 paintings, with works by all three artists mixed together. Each time you see a new painting, you have to ask, “Which artist is this?” and actively recall the unique characteristics of each style.

This process of constantly switching gears creates what cognitive scientists call “desirable difficulty.” Because your brain can’t go on autopilot, it’s forced to notice the similarities and differences between concepts, leading to a much more robust understanding of the material. Research consistently shows that while interleaving may feel more challenging during study sessions, it leads to significantly better performance on future tests and real-world applications.

Tools and Platforms to Supercharge Your Interleaving Practice

Adopting a new study method is easier when you have the right tools. Fortunately, many leading educational platforms are perfectly designed to help you implement interleaving. Here are a few verified resources to get you started.

1. Khan Academy for Mixed-Concept Practice

Khan Academy is a free, world-class educational resource that excels at providing interleaved practice, especially in STEM subjects.

  • Verified Purpose: Khan Academy’s mission is to provide a free, world-class education for anyone, anywhere. Its platform uses mastery learning, which includes quizzes and unit tests that naturally mix concepts from an entire topic.
  • How to Use It for Interleaving: Instead of only doing the practice exercises immediately after a video lesson (blocked practice), jump straight to the “Unit Test” or “Course Challenge.” These assessments pull questions from all the lessons in a unit, forcing you to switch between different problem types and formulas. This is interleaving in action.
  • Official Source: https://www.khanacademy.org/

2. Anki for Customizable Interleaved Flashcards

Anki is a powerful, open-source flashcard program that uses spaced repetition. With a little setup, it becomes an unbeatable tool for interleaving.

  • Verified Purpose: Anki is a program which makes remembering things easy. Because it's a lot more efficient than traditional study methods, you can either greatly decrease your time spent studying, or greatly increase the amount you learn.
  • How to Use It for Interleaving: The key is to avoid studying one small, specific deck at a time. Instead, combine multiple related decks. For example, if you are studying biology, put your cards for “Cellular Respiration,” “Photosynthesis,” and “Mitosis” into one large “Biology” parent deck. When you study the parent deck, Anki will show you cards from all topics, forcing you to constantly switch contexts.

Pro-Tip: You can also use tags to create “Filtered Decks” for a temporary, mixed study session without permanently moving your cards.

3. Brainscape for Adaptive, Mixed Review

Brainscape is a web and mobile study platform that uses a scientifically optimized algorithm to repeat flashcards in a way that maximizes retention.

  • Verified Purpose: Brainscape helps students and professionals learn faster by using confidence-based repetition. Its system is engineered to work with key cognitive science principles.
  • How to Use It for Interleaving: Brainscape’s algorithm naturally interleaves concepts. When you study a “Class” (a collection of decks), the platform’s smart study feature mixes cards from all the included decks. It presents cards based on your confidence rating for each one, ensuring you are constantly retrieving information from different topic areas within the same session.
  • Official Source: https://www.brainscape.com/

Practical Steps to Start Interleaving Today

Ready to give it a try? Here’s how you can integrate interleaving into your routine.

  1. Identify Related Concepts: Interleaving works best when you mix topics that have some relationship. For a math class, mix different types of algebraic equations. For a language class, mix different but related grammar rules (e.g., past, present, and future tenses).

  2. Plan Your Study Sessions: Instead of dedicating Monday to Topic A and Tuesday to Topic B, dedicate both days to studying Topics A and B together. Spend 25 minutes on A, then 25 minutes on B, and then do a practice quiz with problems from both.

  3. Don't Confuse Interleaving with Randomness: Don't mix completely unrelated subjects, like calculus and art history, in the same rapid-fire session. The goal is to help your brain distinguish between similar ideas, not to cause cognitive whiplash.

  4. Embrace the Struggle: Interleaving will feel harder than blocked practice. You will make more mistakes initially. This is not a sign of failure; it’s a sign that your brain is building stronger, more durable connections. Trust the process.

For more insights into the science behind this technique, check out the resources from The Learning Scientists, a team of cognitive psychologists dedicated to making scientific research on learning more accessible.

A Smarter Way to Learn, Not a Harder One

Interleaving isn't about studying more; it's about studying smarter. By replacing long, monotonous blocks of single-topic study with mixed practice, you train your brain to be more agile and adaptable. You’re not just memorizing facts—you’re learning how to identify problems and retrieve the correct solution from your mental toolkit.

The next time you sit down to study, resist the urge to drill one concept into the ground. Mix it up. Use tools like Khan Academy or Anki to create varied practice sessions. It may feel a little uncomfortable at first, but the long-term rewards—deep knowledge, flexible skills, and lasting retention—are well worth the effort.