By: Megan Smith, Yana Weinstein, & Fergus Dark

Interleaving can be a tricky concept and is often confused with spaced practice. In laboratory studies, we can disentangle the effects of interleaving and spacing to show that they are both helpful on their own to produce learning (1), (2). However, in classroom practice, it can be difficult to implement interleaving on its own, without spacing. Interleaving often creates spacing, and spacing can at times create interleaving. This, of course, isn’t a bad thing. Both tend to improve learning, and research shows that combining many of the 6 key strategies from cognitive psychology can be the most powerful ways to promote learning. All of this said, we argue that it is still important to understand and utilize interleaving, especially when teaching subjects that involve problem solving (e.g., math, physics).

So, what exactly is interleaving?

An anecdote may shed some light. We recently (June-July 2017) visited a number of schools and school alliances in England to run workshops on the science of learning. One of the places we visited was Samuel Ward Academy Trust, and while there we spent an hour with around 20 students ranging from 9 to 18 years old. We asked the students to tell us what they do to help themselves learn. We did this before even mentioning names or explanations of the strategies so that we could later link the strategies to concrete examples of things the students were already doing.

One student, Fergus Dark, brilliantly explained how he “jumbles it up” during learning. What he was describing was a lot like interleaving, though he was calling it something else. (We actually think the term he used is more easily understood than "interleaving"!) We love the phrase “jumble it up”, and asked him to write out his explanation. Here is his description in his own words:

“Jumbling is a memory technique for recalling information. Often when revising, you learn key points, terms or information in a certain order. So when it comes to the exam you will remember it in that order. The paper may ask you to write it out in a different order or perhaps only ask for one key point. This is when jumbling comes in handy. Instead of spending time and effort trying to rearrange the info and possibly losing marks, when revising practice recalling the information in separate chunks and do not get to know it in the order laid out in front of you. Once you have nicely jumbled it all up in your head and can remember each section separately and quickly, then you`re good to go!” – Fergus Dark, Year 8 (7th grade equivalent) student from Thomas Gainsborough School in Great Cornard, England.

(Note: this blog may help Americans translate some of the technical terms from the UK Education system to the American Education system.)

Fergus used the example of learning how to give directions in German to explain his jumbling technique to us. At first, you learn how to give the directions in a certain order. For example, you might learn how to say turn right, then learn how to say turn left, and then learn how to say go straight. However, when you’re actually using these phrases, you want to be able to recall them in different orders. So during practice, you should jumble up the order of the German directions. This will make it easier to use them later on.