Studying Smart, Part 3: Interleaving
No one enjoys spending hours practicing the same skill over and over. By diversifying your study routine and interchanging multiple skills, you can learn more effectively.
This is the third post in our Studying Smart series, we look at reliable, practical skills that any student can cultivate and every student can benefit from. In the first two installments we covered repetition with variation and productive failures—practices that address when and how to study effectively. This week, we’re going to look at what to study, based on a practice called “interleaving.”
Interleaving means diversifying one’s practice by interchanging multiple skills in sequence. This approach is often contrasted with practicing a single skill in repetitive “blocks.”
The practice of interleaving originally arose as a way to improve outcomes in athletic activities. Imagine, for example, you were trying to improve your tennis game. Instead of devoting a few hours each day to a single element of the game—serves on Monday, backhands on Tuesday, forehands on Wednesday—you practice each of these techniques in smaller quantities daily. You will have improved more by interleaving than practicing in blocks.
A Test Case in Math
Since the original study, research on interleaving has shown promise in a range of academic disciplines. (You can read more about the latest research here.) Part of what makes it effective with math, in particular, is that you’re reinforcing familiar ideas but in a new context, so that you have a fuller picture of something you previously knew from just one vantage point. Conversely, “blocking,” especially when overused, encourages rote memorization that loses sight of the conceptual basis for an idea, as well as how to manipulate this idea.
Imagine a student is learning prime factorization. A student may devote so much energy to memorizing that singular process that they have no sense of how it functions relative to other related ideas, such as greatest common factors or adding fractions of unlike denominators. And when similar procedures come along, they all seem similar and easily confused.
There is a risk in attempting to interleave related practices without the foundational knowledge underlying them. To make interleaving work, it needs to be grounded in knowledge or skills a student already has. To go back to the last example, you cannot interleave prime factorization with greatest common factors and adding fractions unless you already know something about multiplication and division. This means teachers and students need to show some discretion in knowing exactly what to interleave and the foundations common to each skill.
Beyond Quantitative Skills
How well does this technique extend beyond math? There are some clear applications for other domains, like vocabulary, either in a native or a foreign language. Rather than attempting to memorize a handful of words simply by re-reading definitions over and over, try interleaving your study of vocabulary with grammar and writing exercises. For each word, generate the following:
Find two sample sentences.
Write two original sentences.
Use the word in a declarative sentence.
Use the word in a question.
Write a story that integrates all of the words.
You can likely apply this approach to any discipline where you need to learn a variety of skills. Just remember to start with a foundation of established knowledge and then freely vary your practices from there.
The value of interleaving done right is immense: improved memory retention, greater intellectual flexibility, and quicker, deeper understanding. If you combine this practice with the other study habits we’ve discussed—productive failures and repetition with variation—you’ll find yourself better able to tackle any assignment or assessment that comes your way.