Interleaving: Why mixing subjects might actually make you a better student

What is interleaving?

Interleaving is a study technique where you mix different topics or problem types within one study session. It is said to improve memory and help you apply knowledge more flexibly.

How does it work?

For example, instead of studying maths, English and biology for 40 minutes each you could study them like this: 

1. Maths - 20min

2. English - 20min

3. Biology - 20min

4. Maths - 20min

5. English - 20min

6. Biology - 20min

It works the same within a subject. Let’s say you need to practise division and multiplication both for 20 minutes. Now, instead of studying first division and then multiplication for 20 minutes you interleave them - study division for 10 min, then multiplication for 10 min and repeat.

Why does it work?

At first, interleaving feels harder than studying one topic at a time (called blocking). However, this difficulty is actually what makes it effective. When you switch between topics, your brain has to work harder to recall and apply information. This strengthens memory and helps you understand how different ideas connect. As a result, interleaving improves long-term memory and makes it easier to use what you’ve learned in tests.

My experience with it

To be honest, I hadn’t heard of interleaving before researching study methods. So these are my first impressions after trying it:

Within one subject I chose to interleave between solving different types of problems in physics to practise for my upcoming test. I started with pressure problems, then moved to uplift force, and finally combined both. All for 10 min and then repeat twice. I was surprised that the switching didn’t bother me. I think it’s because I was switching between different types of problems, but they were still the same subject. I quite liked interleaving like that and I felt like it brought some diversity in my studies.

Within one study session I chose to interleave between history and biology, because in biology we learned about Charles Darwin and in history we were learning about the same century, when Charles Darwin had made his discoveries. I studied history for 20 minutes, then biology for 20 minutes, and repeated this twice. With this version the switch bothered me more, because I was just starting to get in the zone when the timer went off and, as it is supposed to, it felt difficult constantly switching back and forth. But I do feel like I made more progress and kind of multi-tasked between the subjects learning both of these at the same time.

Here is an overview of the Interleaving method:

Preparation: None, except maybe thinking a bit about what kind of subjects or topics can fit for interleaving.

Time: In terms of time, it took me the same amount of time as blocking would’ve. So it really depends on your preferred duration. I liked that interleaving within the subject I had less amount of time and interleaving within a study session I had more time to focus on each of the subjects.

Efficiency: It took me the same amount of time, but I think I got more done. Because with blocking I would’ve been tired of the topic/subject at the end of the session, but because of interleaving I was switching the topics and never got bored. I kind of had a burst of energy when switching the topics/subjects. So, overall it was quite efficient.

Annoying: As I’ve promised to keep it real, I’m not going to lie when I say it was annoying. I think it’s mainly because it was my first time trying interleaving, but still. I am definitely not used to constantly having to switch between topics and subjects, but that does mean it’s improving my brain and my adaptiveness, which is good. So I guess it’s annoying in a beneficial way. 

Result: I have to admit, I do remember the topics/subjects I learned with interleaving way better than I do other topics/subjects. So it was successful. 

Will I try it again: Probably. I think it just needs a bit of practice to really be able to interleave subjects without feeling overwhelmed. But I really liked how it made my brain work twice as hard. And it had some amazing results.

Personal tip: Make a plan. Seriously. It’s way easier than constantly having to remember what kind of subject or topic comes next while trying to study. Even a simple plan on a Post-it note helps. Otherwise you’ll spend more time thinking about what to study next than actually studying.

When to use it: Between subjects or topics that are somehow related to each other. For example, physics and maths, English and Estonian language or literature and history. Between topics: you could learn geometry's different shapes, English tenses or physic's formulas.

When NOT to use it: It may feel harder when subjects/topics are very different, especially at the beginning. The more you practise the easier it gets to mix subjects that aren't that similar. 

Common mistakes: 

1. Switching too frequently between topics can leave you feeling overwhelmed and lost. I definitely experienced this myself and now I know to make the durations longer. 

2. Rushing through material as fast as you can without fully grasping it. Interleaving is about challenging your brain, not speeding through your study sessions. Even though there is a clock running out it doesn’t mean you have to try to keep up with it - no, study, read, listen at your own pace.

3. Giving up too soon. This is an important one. When I had completed the first round I didn’t really feel like doing the second one, but that’s where interleaving actually starts, this is the part that’s going to tie everything together.

4. Feeling like the timer is controlling you. If you feel like you just got in the zone and the timer has already run out - don’t worry, you are allowed to make the duration longer.

Overall, I think interleaving is a very effective study technique, even though it feels more difficult at first. It takes some practice, but it can improve both understanding and memory. I would recommend trying it, especially if you feel bored or stuck studying one topic for too long.