Interleaved learning - many people aren’t familiar with the term, yet it is by no means a new development. It was first described as varied or mixed practice some 30 years ago. Increasingly though, interleaved learning is being seen as a powerful technique for enabling more efficient learning. The technique is a proven way of building your knowledge and skill set across a broader focus, strengthening recall and improving retention.
Interleaved learning centres around us varying the skills or subject matters we learn, rather than focussing on one at a time, the theory being that the variation improves our memory recall, and brings greater retention.
The path of our learning takes many turns. It can rise and fall, up peaks and down troughs. Butcher, baker or candlestick maker, we all have to learn new skills through our life. Our learning certainly doesn’t finish at the end of our formal education. We move forward, seeking growth, development and the opportunity to better ourselves. Our workplace eventually replaces the classroom as we seek that growth, those opportunities, in our professional lives. In the modern age, digital technology assists us in that goal, bringing us the opportunity for professional development through e-learning. And we know that how we learn is just as crucial, just as fundamental as what we learn, the two are mutually beneficial.
Let’s ask a question. A question you probably haven’t read in a blog post on learning and development before today. What would you rather learn - how to play a trumpet, or how to become a cheese expert? (Well, we did say you’d probably not seen such a question before!!)
The two are not as far apart as you’d imagine. They would both require you to process a huge amount of varied information, to practice more than one skill simultaneously, and to build the pathways to memory recall in the brain. The trumpet student needs to learn how to hold the trumpet, breath control, the mathematics involved in reading music, the mechanics of the instrument, the position of the mouth. You'd need to understand concepts such as tone and pitch, as well as being able to learn to use the instrument expressively and dynamically. Multi-faceted, varied learning of many skills at once. Similarly, our cheese expert. They would need to understand the process of how the cheese is made from the grass to the cow, from the milk to maturation, and from there to the cheeseboard. The ageing process, atmospherics, the chemical and physical construction of the finished product, the difference between geographical areas and producers and the history and traditions of each cheese. Again, this is interleaved learning. Though both are learning one subject, both subjects are based on learning an array of skills.
So much to learn, so many ways of learning. So, okay, it is all about practice, and practice makes perfect, that we know. Our main method, the one we would all recognise and identify with, is block learning. Block learning happens when we pick a particular subject or skill set, and concentrate on learning all we can in one course or session. One single focus. One subject. Then we move on to the next subject. We simply identify the basic elements of the subject, practice some exercises and tests to help us process and learn the information, achieve a certain satisfactory level of knowledge and proficiency, and then move on to repeat the entire process with the next subject, the next topic. One skill at a time, learned through repetition over a set amount of time. This is block learning. Though we already know of its worth as a learning technique, we could be forgiven for seeing it as a slightly formal and potentially unreliable method. And in terms of the learner’s engagement, well, it’s just a little bit boring….
There are many theories as to what makes interleaved learning work, though the exact cognitive mechanism is not known for certain. Let’s look at just a couple of theories.
Clearing the route (retrieval - practice theory)
All learning starts with our prior knowledge on a given skill or subject. In this theory, we need to access that prior knowledge and recall it into our working memory. In block learning, this only happens once- at the beginning of the learning, and we don’t need to repeat it throughout the learning with each remaining skill. Whereas, with interleaved learning, we need to bring that prior knowledge into every stage of the learning, repeatedly, so that we can build those skills.
This theory has been described in an analogous form as walking through long grass to clear a path way. If we simply walk through the grass one time (as in block learning), back and forth once only, we’re still able to find the path a couple of hours later. However, if we repeat the process several times (interleaved learning), we’re able to find it again weeks, or even months later.
Manual or automatic (discriminative - contrast theory)
Another possibility is that interleaved learning works because as we vary the skills we learn, our brain has to adapt, react and function in a different way. If our focus remains on just one subject or skill at a time, such as in blocked learning, then our brain has less to do, and doesn’t need to work quite so hard. Whereas with interleaved learning, the brain must adapt to each new subject, each new demand, by having to work out what prior knowledge is called for. This means that the brain needs to focus more, which can lead to better retention.
For example, if you’re driving a car with an automatic gearbox, you simply put it in D and off you go. You don’t need to worry about hills, or bends. You have a go pedal, and a stop pedal. You need to think about your journey less, point the car in the right direction, and simply press ‘stop’ or ‘go’ until you reach the destination. This is similar to blocked learning. The destination is the same, but the journey is less challenging, more predictable, and less dependent on your focus.
However, let’s consider a manual gearbox as interleaved learning. It forces you to consider the route and the journey, and to regularly assess what you need to do to reach the destination. It tests you to react and adapt along the way, forcing the car to do the same as you go. More focus and care is required, and your attention is challenged all through the journey.
These are just two simple theories that explain what we know about the power of interleaved learning. We know it works, and that it is undoubtedly a useful tool for learning. Learning and Development providers and Managers would do well to bear it in mind when designing courses. As well as improving retention and recall, by adding extra demands onto focus, interleaved learning keeps learners engaged and enthused in their learning.
Variety is the spice of life. And though it may not sound anywhere near as catchy, Interleaving could well be the spice of learning.