A breakdown of...interleaving
"Why don't you switch from AAABBBCCC to ABCABCABC?"
"You lost me at 'A'..."
As a new teacher who continues to absolutely boss this world we call teaching, you may start to be let loose on the SOWs for your subject. Perhaps you have been given control over a particular year group, or you may have had a meteoric rise to HoD and are now thinking 'Oh God, what do I do now?!' Either way, it may be a good time to consider curriculum design and how you will enhance the learning of your students. I will tackle this issue in more detail in a later post, but one consideration may be whether you will incorporate the science of interleaving into your SOW. It is a pretty controversial topic, with evidence on paper not always marrying up with its application in practice, so let this be the start of your research journey. In this week's post, I share my views on interleaving and whether it could work in a History curriculum (surely not!)
First, what on earth is it? Interleaving is the sequencing of topics/tasks alongside other, similar tasks, rather than in blocks. (Umm...what?) Imagine the letters in the image above represent different topics in a Biology curriculum. Using interleaving, students may learn the anatomy of a cell (Unit A), the anatomy of a plant (Unit B), and the anatomy of a human (Unit C) before going back to look at the functions of all three, and so on. This differs to the traditional method of teaching that we all know and love, which involves 'blocked' learning of different topics (All of Unit A, followed by all of Unit B, etc.)
There has been a lot of research into interleaving that is summarised here; however, the main benefits are due to the increased difficulty and challenge ('desirable difficulty') it offers, as well as providing opportunities to strengthen memory over time. More significantly, a sequenced curriculum enables students to compare topics, so that similarities and differences are clearer. Identifying patterns and themes between topics will ultimately provide students with a deeper understanding of topics. For example, here is a study carried out by Kornell and Bjork:
Kornell and Bjork (2008) examined the effects of interleaving in a task that might be pertinent to a student of the history of art: the ability to match paintings to their respective painters. Students who studied different painters’ paintings interleaved at study were more successful on a later identification test than were participants who studied the paintings blocked by painter. (Y. Weinstein, 2018)
But do teachers actually apply interleaving in their departments? Well, I came across a survivor of interleaving at a ResearchEd seminar last year; RS teacher Dawn Cox (@missdcox), who explained the many strategies she uses to improve the knowledge and understanding of her pupils. Along with the commonplace strategies of retrieval practice and spaced learning, she also explained how she incorporates interleaving into her curriculum design. Dawn seemed to be a huge fan of her sequenced SOW and claimed that the knowledge and understanding of her students had improved massively.
"But this would never work in History", I thought, and that was that. I dismissed the concept and moved on to interventions that I could easily incorporate into my department. My initial rejection of the idea was based on the need for students to have a chronological narrative - surely that is the crux of all History teaching?! In my mind, asking students to switch from Hitler to Elizabeth I and back again would no doubt result in misconceptions that Sir Francis Drake and the SS held off an armada from Spain in 1939.
But what if there are two topics that are chronologically parallel - could this provide a rare opportunity to use interleaving?
This sudden throwback to this concept of interleaving came during departmental discussions to change our GCSE curriculum. Colleagues pointed out that there was 'too much crossover' between two of the topics that we were considering for the new GCSE:
> Conflict and tension: The inter-war years, 1918–1939 (The Treaty of Versailles, League of Nations and Hitler's foreign policy leading up to WW2)
> Germany, 1890–1945: Democracy and dictatorship (Essentially the collapse of the Kaiserreich and Weimar governments and the growth of Nazism)
Granted, there was some overlap. In one unit, Germany was mentioned in the context of international relations - the Treaty of Versailles, economic partnerships and Hitler's foreign policy. In another, students would explore the domestic impact of these events - territorial losses, hyperinflation and unemployment. So, this clearly is not the broadest of curricula (although, it must be noted that there are two other topics that run alongside this pair), but my mind then jumped back to that ResearchEd seminar and the concept of interleaving. Could these two 'similar' topics provide an opportunity for sequencing that wouldn't normally exist in History teaching..? Could this improve pupil outcomes and a nomination for teacher of the year???
Then my mind completely ran away from me and I began planning out the 2020/21 SOW in my head. Say that I wanted to buck the trend and attempt interleaving within a new GCSE curriculum, using the two units that were mentioned above - how might that look and what would students gain from it? Here is my thinking...
Below is the traditional SOW structure for those particular units. Students would study Unit 1 (Germany, 1890-1945) before moving on to Unit 2 (Inter-war years, 1918-1939).
But here is the same SOW incorporating interleaving...
Here, the content from both units is sequenced alongside one another, with similar topics occurring in succession. For example, students would learn about the end of WW1 in September (Unit 1), before moving on to look at the impact of this on Germany in October (Unit 2). By doing this, there is an argument to suggest that pupils would better understand the chronological narrative and would be able to contextualise Germany's domestic problems within international affairs. Throughout the year, the class would also have regular practice of all exam questions from both sections of the paper, rather than having four months where only one section is looked at. Eureka! (Or so I thought...)
Ultimately, the jury is still out on whether interleaving would work within a History curriculum and whether I will be trialling this in September 2020 when we switch to the AQA GCSE (my colleagues are no doubt reading this and thinking, "Like hell we are..."). There are some obvious benefits that are explained in the research; however, there are also a few worrying caveats that I think need to be acknowledged:
> Pupil anxiety --> I understand the need to offer challenge to students, but would this be creating too much anxiety for a generation of students who are already under immense pressure? It is hard enough telling them at Christmas "We're now moving on to topic 2 of 4", let alone saying this every few weeks!
> Desirable difficulty --> The benefit of interleaving is that it taps into this idea of 'desirable difficulty' - stretching students just enough that they make continued progress. But what if the topics are too distinct? If this is the case, then there is evidence that interleaving would have no effect, or even a negative effect, on pupil learning.
> Low-ability students --> I think that interleaving would work wonders with the brighter students in a class who can readily spot the patterns between both units. But what about weaker students? A sequenced SOW puts more pressure on students who benefit from a set routine, so I am not sure that interleaving would work for everyone.
> Scalability --> Potentially, I may have just stumbled on a bit of an anomaly in the world of History teaching. Very rarely do two topics complement one another as well as these two, so it begs the question whether interleaving can really work for all History teachers. There is no way, for example, that I could sequence the other two topics from the GCSE course: Medicine Through Time and Elizabeth I!
In Make It Stick: The Science of Successful Learning, Brown et. al. also explain how:
'Teachers dislike [interleaving] because it feels sluggish. Students find it confusing: they're just starting to get a handle on new material and don't feel on top of it yet when they are forced to switch'
Even in the Kornell and Bjork example mentioned earlier, Art History students persisted in preferring blocked practice when studying the work of different artists, even though they could see for themselves that their marks were higher when the practice was sequenced using interleaving. I think this explains the reservations that many students and teachers have with interleaving - we like to get one thing done completely before moving on; switching when a task is unfinished feels 'messy' (just look at my kitchen...)
So perhaps come back to this blog in eighteen months time to see whether I go ahead with an interleaved GCSE curriculum, because for now, I am just not sure. A compromise may be that I continue to incorporate interleaving in other ways, such as setting revision homework or starter quizzes from Unit 1 throughout the teaching of Unit 2. But this perhaps slips into the fields of 'spacing' and retrieval practice rather than 'interleaving', so I may just leave it there and avoid this minefield altogether...
For more information on the benefits of interleaving, here is one of its leading proponents, Robert Bjork: