Episode 9 - Bite-Size Research on Interleaving Categories

Show Notes:

This is a bite-size research episode, where we briefly describe research findings on a specific topic. This week, Yana talks about interleaving while trying to learn how to categorize things.

In the last episode, we talked about the research on interleaving. The idea behind interleaving is that students might switch up their studying so that they are not studying the same idea or concept for a long time, but instead are alternating the material they are studying. Mainly, the benefits that we discussed come from studies of motor learning (1) or problem solving (2). So, we talked about studies where students were given math homework based on one type of problem, or math homework with problems from different areas that required different approaches to solve them (2).

In this episode, Yana talks about a different type of learning that has also been shown to benefit from interleaving: learning which items are part of one category, and which are part of another. Earlier research on this topic looked at how people learn to classify paintings by different artists (3), or different types of birds into a taxonomy (4). In these studies, students aren’t interleaving problem solving or retrieval practice. Instead, they are just studying examples from different categories. And in these studies, interleaving examples from different categories generally helps the learner extract the main features of each category. 

The set of studies described in this episode (5) applied this type of design to students learning chemistry. In this set of experiments, students studied visual representations of chemicals, as shown below. Each diagram shows the structure of the elements, and how they form the chemicals. 

Image from Eglington and Kang (2017)

Image from Eglington and Kang (2017)

They saw 12 examples of chemicals in each of 5 categories - 60 examples in total. Then, when they came back two days later, students were shown new visual representations from these 5 chemical categories, and were asked to determine which category they fit into. What differed between the two groups of students was whether the examples from the 5 categories had appeared interleaved or blocked during the study phase. Those who had seen the chemicals interleaved during study got an average to 85% on the categorization quiz 2 days later, compared to only 71% in the blocked condition. In a follow-up experiment with more complex materials, students who interleaved performed at 65% and students who blocked performed at 49% on the later test, showing the same pattern of results. The authors also found that participants in the interleaving group outperformed those in the blocking group even when both groups were given cues about similarities and differences between categories. 

This type of learning - that is, learning how to categorize visual representations of chemical elements - may seem quite basic, but it is actually very important for those who want to go on and study chemistry in more depth. For example, knowing which chemicals belong to which category is essential to understanding how the chemicals interact. And, the same can be said for any subject: knowing the basics is essential to later understanding of more complex abstract ideas.

Tune in over the next two months to learn about the remaining two strategies, concrete examples and dual coding!

The Learning Scientists Podcast is funded by The Wellcome Trust.

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(1) Shea, J. B., & Morgan, R. L. (1979). Contextual interference effects on the acquisition, retention, and transfer of a motor skill. Journal of Experimental Psychology: Human Learning and Memory, 5, 179-187.

(2) Taylor, K., & Rohrer, D. (2010). The effects of interleaved practice. Applied Cognitive Psychology, 24, 837-848.

(3) Kornell, N., & Bjork, R. A. (2008). Learning concepts and categories: Is spacing the “enemy of induction”? Psychological Science19, 585-592.

(4) Tauber, S. K., Dunlosky, J., Rawson, K. A., Wahlheim, C. N., & Jacoby, L. L. (2013). Self-regulated learning of a natural category: Do people interleave or block exemplars during study?. Psychonomic Bulletin & Review20, 356-363.

(5) Eglington, L. G., & Kang, S. H. (2017). Interleaved Presentation Benefits Science Category Learning. Journal of Applied Research in Memory and Cognition, 6, 475-485.

Episode 10 - Concrete Examples

Episode 8 - Interleaving