Interleaving Is Less Effective When Taking Notes
(Cover image by Tim Hauswirth on Pixabay)
by Cindy Nebel
Interleaving refers to the strategy of mixing up the order in which material is reviewed or practiced instead of blocking materials. This works particularly well when learning new categories of items that are difficult to distinguish - things like different types of math problems (1), birds(2), or paintings by different artists (3).
However, in most situations, interleaving is examined in the laboratory so that we can control other variables that might impact our ability to see the effect. This is super important for understanding the underlying mechanisms for how we learn and remember. Sometimes, though, the way things happen in the so-called “real world” matter for the types of recommendations we want to make for educators.
The study I’m reviewing today took place in the laboratory, but examined a common situation in the classroom that might matter: note-taking (4). If students are able to take notes while learning, does that change the degree to which interleaving helps them?
In this particular study, participants studied paintings by different artists. Each participant got to see some of the paintings in a blocked fashion (6 paintings by Artist A followed by 6 paintings by Artist B) and some of the paintings in an interleaved fashion (Artist C, D, E, C, F, E, D…) and half of the participants were given some blank paper and told to take notes in order to help them learn. Finally, participants took a test where they had to identify new paintings and, in some situations, they were able to use their notes and in others they weren’t.
The results showed that interleaving was better than blocking in the typical laboratory situation where participants don’t take notes. When students did take notes, the effect pretty much disappeared, and when participants could use their notes on the test? They actually did better on the blocked artists.
So what’s going on here? Why do interleaving and note-taking interact? There are a lot of potential mechanisms and this an area ripe for further research. However, there are a few things we can try to unpack here. One possibility is that note-taking hurts interleaving. That is, by taking notes, maybe students pay a lot more attention to the specific item on the screen and stop making comparisons across items. That item-specific processing would certainly eliminate the benefit that comes from interleaving. Another possibility is that interleaving hurts note-taking. That is, students are used to seeing things blocked. They know how to process material from textbooks and homework assignments that ask them to do similar processing over and over again. Asking them to switch between materials might actually hinder their ability to take effective notes.
I think there’s another important take-away here though too. Note-taking, even in the absence of ever looking at those notes again, changed the way that students processed information. And the quality of those notes mattered. When students wrote down more of the critical characteristics that distinguished artists, they were more likely to get that artist correct on the test. One thing that might be happening is that students make their vague, abstract ideas concrete and memorable by writing them down. Importantly, these were not verbatim notes. Students didn’t have verbal material that they could copy off a slide or straight out of an instructor’s lecture. They produced these ideas… and that fact is probably key to the learning benefit they received.
Bottom Line
Here is my advice after reading this study:
1) Interleaving is still a good thing for distinguishing between similar topics.
2) Don’t change all your practices after reading a single study. But be on the lookout for more research on this topic. It’s needed.
3) Students don’t walk around with their notes in the real world. Make exams match the way you want students to be able to use your materials later in life in order to maximize their likelihood to transfer from your class.
4) Teach students to take good notes and maybe stop providing so many words on slides. Encourage them to put ideas in their own words, to organize, think, and question material in order to make notes more effective. More on that idea here.
References:
(1) Taylor, K., & Rohrer, D. (2010). The effects of interleaved practice. Applied Cognitive Psychology, 24(6), 837-848.
(2) Wahlheim, C. N., Dunlosky, J., & Jacoby, L. L. (2011). Spacing enhances the learning of natural concepts: An investigation of mechanisms, metacognition, and aging. Memory & Cognition, 39(5), 750-763.
(3) Kornell, N., & Bjork, R. A. (2008). Learning concepts and categories: Is spacing the “enemy of induction”?. Psychological Science, 19(6), 585-592.
(4) Little, J. L., Fealy, J. C., Kobayashi, K., & Roth, S. (2025). How note-taking and note-using affects the benefit of interleaving over blocking. Memory & Cognition, 1-17.
