How can I help my students really master the material?

Dear Aggie,

I was intrigued by your answer to "Stop the Cram" a few weeks ago. You discussed strategies to promote long-term learning (and avoid cramming). I feel that my students are having a harder time on my (cumulative) final exam, where they encounter a variety of problems that rely on a variety of concepts and topics. I was wondering if you had any additional ideas to help my students really integrate the course material and pull it together as we go?

~Seeking Mastery

Dear Seeking,

As we discussed with "Stop the Cram" in our Feb. 9 Dear Aggie post, some of the strategies to promote longer-term learning (and discourage cramming) include frequent testing and quizzing (retrieval practice) and spacing out the learning (vs. "massed" practice or learning).

It turns out that there is another strategy that we can build into our courses and that we can encourage our students to use in their studying. This is known as interleaving. Rohrer (2012) gives a very nice review of interleaving, and I am drawing from this review for the information that follows.

What is interleaving?

It is helpful to contrast interleaving with its "opposite"—which is "blocking". In blocking, students practice one topic/concept/strategy at a time, then move on to another: AAAAA, BBBBB, CCCCC etc.

Interleaving has students practice and learn those same topics/concepts/strategies, but in a "mixed up" format: ABC, ABC, ABC, ABC, ABC

You can see that students have the same amount of exposure to each topic with blocking and with interleaving, but the order and arrangement of exposure differs.

Why use interleaving?

Interleaving promotes better long-term learning, fosters problem-solving skills, and helps students transfer knowledge to new situations. While there are numerous examples illustrating the impact of interleaving, I am highlighting just a few here, based on summaries from the resources listed below.

Art Example

A classic example comes from art, in which students need to be able to distinguish landscape paintings by different artists. The blocked approach is to show students several landscapes from artist A, then several landscapes from artist B, then several landscapes from artist C, etc. The interleaved approach is to show students a landscape from artist A, then one from artist C, then one from artist B, etc. When students were shown the same number of landscapes from the same number of different artists in each format, the students who learned in the interleaved format substantially outperformed their blocked peers at identifying the artist of never-before-seen landscapes.

French example

Oana Cimpean from our Teaching Academy shared this experience from her teaching of French: Students learn two different past tenses in French. Traditionally, these tenses are taught separately, and students are given numerous opportunities to use each tense. However, these tenses occur together, sometimes in the same sentence. The only way for students to be able to use these tenses correctly, is to teach them both at the same time, to interleave.  This ensures they develop discerning skills.

Tennis example

Another example comes from tennis. Coaches may have athletes practice exclusively forehands, then exclusively backhands, then exclusively serves. Players will certainly be able to perform each of these in isolation. But in a tennis match, players use all of these as demanded by the match. So practicing them in an interleaved format is a more realistic approach to prepare for what the players will encounter.

While interleaving necessarily promotes spacing (encounters with a particular topic are spread out over time, and not massed/crammed), the benefits of interleaving seem to go beyond a mere spacing effect. A few studies have explicitly controlled for spacing in an interleaving intervention, and the "mixing" of topics in interleaving seems to enhance the spacing effect. Interleaving requires students to examine each problem and determine the optimal approach and solution. In blocking, students apply a specific approach/solution repeatedly, without necessarily recognizing why that approach is the best one for that problem.       

Supporting interleaving

• Students can use interleaving as they study. For example, a pre-nursing student may interleave studying of biology, chemistry and math (instead of blocking several hours for each).
• If students use flashcards to test themselves, encourage them to combine flashcards from different topics or subjects, and to shuffle them.
• You can promote interleaving by creating assignments that have questions on new material, as well as some questions on prior material.
• You can also switch things up in class, by spending some time on new material, then having a discussion that integrates the new material with old material. For example, in a science class, ask students to design an experiment—an "old" skill—to test this week's new idea. Or you could ask students to consider how this new material is different from what they learned last week and/or how it is similar.

Heads up: Interleaving feels hard (students prefer blocking)

While interleaving is clearly better for long-term learning, in the short-term, blocking can lead to faster learning. Blocking "feels" easier to students—they can work through a set of 10 similar problems much more quickly than through 10 different problems, each of which requires thought about how to approach it. And students definitely prefer blocking. In fact, they incorrectly predict that they will do better on an exam after blocking than after interleaving. This means we may have to "sell" the benefits of interleaving, and make it more palatable by e.g., asking fewer practice problems than we would in a blocked practice set. Yes, interleaving is challenging, but it is a "desirable difficulty" (see resources below). We can talk about other desirable difficulties in a future post.

I hope that this gives you some food for thought to help your students truly master your course material and apply it to new situations.

~Aggie

Resources

Bjork, E. and Bjork, R. 2009. Learning. Making Things Hard on Yourself, But in a Good Way: Creating Desirable Difficulties to Enhance Learning. Chapter 5 in Psychology and the Real World. Eds Gernsbacher, M.A., Pew, R.W., Hough, L.M. and Pomerantz, J.R. FABBS Foundation.

Nguyen, H.P. 2021. How to Use Interleaving to Foster Deeper Learning. Edutopia. https://www.edutopia.org/article/how-use-interleaving-foster-deeper-learning/

Persellin and Daniels. A Concise Guide to Teaching With Desirable Difficulties. 2018. Stylus Publishing, Sterling, VA.

Rohrer, D. 2012. Interleaving helps students distinguish among similar concepts. Educational Psychology Review 24, 355-367.