Regularly Revisit
Our students experience a vast amount of knowledge throughout their school curricula. We teach them so much knowledge throughout their time at school but how much of it do they remember and use each year of schooling? How much of it is remembered years after leaving school? Can we teach so that our students do remember and use what we teach well into their twenties and thirties?
Investigations into cognitive human architecture has found that, although our working memory is extremely limited, our long term memory is limitless. Which means that we can learn vast amounts of knowledge. But because we can it doesn’t necessarily mean that we do. The limitations of working memory are partly to blame but perhaps it is what we, as teachers, plan for in our curriculum that explains why our students don’t always remember what we teach them.
Perhaps this is because we don’t revisit learning often enough and as a result that learning weakens quickly over time.
Through regular revisits our students can increase the strength of their learning. Bjork’s ‘New Theory of Disuse’ gives us a useful frame of reference. In this theory Robert & Elizabeth Bjork propose a model of our memories as either having high or low storage strength and high or low retrieval strength. Retrieval strength is a sign of how accessible the learning is, so the higher the retrieval the more mastered the material is and students will be able to quickly access it.
Joe Kirby, through his Pragmatic Reform blog (which I’d highly recommend), shared a useful grid that helps explain Bjork’s model of memory:
The aim of our instruction should be to get to ‘mastered’ but far too often as our students approach exams they sit well within the ‘crammed’ section. This highlights that although the information is accessed for their exam, as it has a high retrieval strength, it is not held in long term memory to be accessed months or years later as it has low retrieval strength.
This also helpfully explains why I often find it difficult to share my Advanced Higher Graphic Communication learning, it is buried somewhere within my brain. However, after a few cover classes it comes back to me and increases in retrieval strength. This goes some way to helping us figure out what to plan for.
There’s no surprises in that I think we need to regularly revisit material we teach. And to do this we must employ some desirable difficulties. These are counterintuitive practices that have been shown to provide much better long term retention of learning. So what are these desirable difficulties and how do they help us learn through regular revisits of the material?
Spacing
In short, spacing is when you present material repeatedly over set intervals. It is opposed to massed or blocked practice and has been shown to be a much better indicator of learning and long-term retention.
In the classroom spacing your instruction and practice tasks over time is much better than blocking them together. For example, if you are teaching fractions in Mathematics and are planning for 10 drill questions, instead of competing all 10 in the same lesson complete 3 with the class and then save the rest for next lesson, next week or next month. The same amount of practice has been undertaken by the students but the difficulty of figuring out which strategy to use (as it will be mixed in with other strategies you are teaching) is a desirable difficulty and will lead to gains in student learning.
Many teachers currently do this through retrieval practice tasks such as Do Now’s where there are questions from last lesson, last week and last month. Other will do this through comprehension questions during the Practice phase of instruction. There are no hard and fast rules to what can be spaced and how to do it, simply making the task effortful can produce gains in long term retention of learning.
The ‘rule of 3’ comes to mind. Rawson & Dunlosky (2011) recommended that:
Our prescriptive conclusion for students is to practice recalling concepts to an initial criterion of 3 correct recalls and then to relearn them 3 times at widely spaced intervals
A handy suggestion for planning then could be to expose your students to Recall material 3 correct times, generating a high level of success, and then through regular revisits that are spaced at longer intervals a further 3 times. It is suggested that the longer the interval and closer to forgetting the material the better. It is worth planning to revisit material quite a few weeks after initial exposure, the longer the better. However, not too long as we don’t want to make retrieval too difficult. It is a delicate balance.
Interleaving
Interleaving is when we mix up the order in a set of tasks or examples. Instead of presented the 10 drill questions, as suggested above, it is much more difficult yet desirable, to present the questions in a mixed up order with different tasks.
Take learning basic shapes as an example. Imagine students are being tasked to recognise circles, triangles and squares. It is often seen that they would practice by recognising 5 circles followed by 5 squares and so on. However, interleaving research suggests that it would be better for long term learning if the recognition practice was mixed up. So, they would be presented as square, circle, triangle, circle, triangle square.
This mixing up of practice requires our students to recognise or choose different strategies to answer each questions. This is much more like real life as it never comes in blocks of ten, no two cars that drive past are the same on a regular basis.
Interleaving is best suited to material that could be easily mixed up and when it provides a desirable difficulty to learning. Is it going to be effortful enough to make Recall challenging? should be the question a teacher is asking when designing interleaved tasks.
Testing
One of Bjork’s best phrases is ‘using our memory shapes our memory’ and this is where testing regularly really helps us master material. The basic act of retrieval during a test or low stakes quiz helps us remember the things we recall, and increases their storage and retrieval strength. The more regularly we revisit material through low stakes quizzing the closer we take students to mastering the material.
Testing students regularly can be seen as counterintuitive but consider this great illustration provided by David Didau:
Which of these study patterns is more likely to result in long-term learning?
1. study study study study — test
2. study study study test — test
3. study study test test — test
4. study test test test — test
Most of us will pick 1. It just feels right, doesn’t it? Spaced repetitions of study are bound to result in better results, right? Wrong. The most successful pattern is in fact №4. Having just one study session, followed by three short testing sessions — and then a final assessment — will out perform any other pattern. Who would have thought?
Although this may seem counterintuitive it has so many benefits for helping our students remember the material we teach well beyond schooling. Regular low stakes testing is a much better learning strategy if we want our students to master the many concepts we throw at them. But how often do we plan for these in our instruction?
The next time you deliver material try planning to regularly revisit it through spaced, interleaved, low stakes testing. It might just send our students on the road to mastering the material we present. Furthermore, these strategies don’t just apply to teaching and our instruction, there may be some mileage in teaching them to our students so that they can develop good habits for revision. Something I will explore further in future posts.
