I first came across the concept of what the research psychologist Will Thalheimer PhD terms “spaced learning”, by accident. Like anyone who has ever had to learn something at school, I found to my own detriment that trying to commit material to memory the night before a test could be problematic. By my own admission I was never that bad at this kind of learning, but equally I always knew that if I left things too late, I could end up making my life more difficult. Teachers often stressed the importance of going over material more than once, but I was always interested in whether there might be a more efficient way to memorize information.
I’ve played the guitar since I was 17 (I'm now 29) and, after a number of years of regular practice, I began to notice an intriguing pattern. I would often try to challenge myself by learning new tunes (as I still do), and it was when I tried to learn particularly difficult licks or chord progressions that I encountered the phenomenon of improved progress and memory retention as a result of spacing my learning. I realised that by increasing the intervals in between my practice sessions, over time, I could derive additional benefit from those sessions.
Day one would always be tough - I'd struggle to string notes together and the correct timing of the tune would take a back seat. If I left it a few days and then came back to the notes, I'd almost always be back to square one, but if I revisited the tune the following day, I'd often find that the particular sequence of notes that I'd been struggling with now seemed to make more sense to my fingers. So far so obvious I hear you say. It was what I discovered next that surprised me.
If I practised the tune everyday for many days in a row, I'd eventually end up learning it fairly well. This was an approach to learning that worked in principle, but which was time-intensive, and initially progress could feel a little slow. However, as a fortuitous result of my lazy practice efforts, I noticed that if I revisited the tune at ever-increasing intervals, for example, the next day, then two days later, then four days later, then a week later, and so on, I found that each time I practised, not only would I experience progress every time I sat down to play, but also in the long run I would be able to recall a tune better, say, a month later, and what's more, the overall amount of time that I'd had to invest in practising the tune was significantly less than if I'd doggedly rehearsed it day after day.
What I'd encountered is an unusual feature of the human brain that scientists are only now beginning to understand and which remains the subject of considerable debate. As I stress in The Holy Grail of Exam Success, sleep plays an integral role in memory consolidation. The process of spaced learning at increasing intervals is therefore an advanced extension of what I describe in my book and a method that may not work in every scenario, but which is definitely worth giving a go.
In very basic terms, when you first try to learn something and commit it to memory, the connections that form in your brain are weak. Therefore, in the early stages of learning, you need to nurture those connections by returning to what you’re learning on a fairly regular basis. Much of the science that allows for the formation of neural connections happens while you sleep, so it’s very important to have breaks in between learning sessions, and it's for this reason that trying to cram in the early hours of the morning before an exam is such a bad idea!
After the initial connections have formed, it's then that the human brain starts to reveal its powers. As I understand it (based on studies that I’ve read), to benefit from the effects of spaced learning at increasing intervals, it seems that you need to give the progressively more complex neural connections in your brain greater periods of time to ‘crystallise’ in between learning sessions. If you do this, you should find that in the long run (and perhaps counterintuitively), your memories will be stronger and last for longer than if you try to intensively study and memorize material over a shorter period of time, and then don't revisit that material again.
Lastly, if you want to ensure that you commit facts and figures to your long-term memory, you need to occasionally revisit material after a longer period of time, say, two months later, then four months later, and so on. To use the example again of the guitar, there are certain tunes which I might not have played for many months or even years, but provided that I occasionally revisit them, the process of running through the same notes refreshes the existing neural connections, meaning that I can rest assured that the memory will remain intact and won't need re-stimulating again for a long time to come.
Try it and see for yourself - I think you might be surprised by the results. Notwithstanding, it’s important to realise that this is still an area that provokes considerable scientific debate. Studies are not conclusive as to what works best when it comes to memorizing material, therefore by all means test run the technique described, but if it doesn’t work for you, then don’t fret (no pun intended). For more on this topic, the following paper is a good place to start: https://www.phase-6.com/system/galleries/download/lernsoftware/Spacing_Learning_Over_Time__March2009v1_.pdf