When you ask students how best to study for a test, most will say something along the lines of “repeat, repeat, repeat”. This often means sitting down and reviewing the same content over and over, until it “sticks”. This is how I revised for my own exams as a student. Not only because my teachers told me to, but because it seemed to work, at least whilst I was engaged in the process. Research has now shown that this type of learning, sometimes referred to as cramming is not the most efficient, or effective, way to revise at all.
“Repeat, repeat, repeat”, which scholars call “massed practice”, means practising a single task over and again without a break. Like this, knowledge bounces around in the short-term memory, making it seem as if the student knows it. However, there has been no repeated retrievals, and re-consolidation, from the long-term memory, so it is unlikely to stick.
As well as recognising the linkage of a memory to other memories, the brain notices how often it is accessed in the long-term memory. It matters far less how many times a book is read whilst “checked out”, than the number of times it is checked out, with the time between each outing being important.
Researchers have also found that the harder you have to work to retrieve a skill or piece of knowledge, the more the practice of retrieval strengthens it. It is as if the brain wants to save itself the trouble of having to work so hard again: “I’d better strengthen this memory, to make life easier in the future.” (Once it has been forgotten, the process is simply re-learning, so one shouldn’t wait too long!)
With spaced, or “distributed” learning, the information has time to leave the short-term memory, so students have to work harder to retrieve, and consolidate, the answer from long-term storage. This can be disheartening, as it is less immediately gratifying than cramming, but creates far more robust memories.
Interestingly, after taking part in studies that clearly show the long-term advantages of spaced learning, many students still say they prefer massed practice. The allure of cramming is that because students are retrieving information from their short-term memory, they notice an immediate result. It appears to be ‘going in’. Though they might do better in quizzes immediately after a lesson, little will be be retained in the longer term.
How long should we wait?
The answer is still a little unclear, and depends on the subject, person and prior knowledge. However, we do know that you ought to wait until the memory fragments have started to be forgotten, at least the next day, but possibly a few days or even a few weeks. Then, when the cracks start to form in the foundations, these problem areas can be patched up better than before, adding stability to the building.
The idea of spacing practice is not entirely new of course; it is the science clearly supporting its effectiveness that is new. Indeed, many educators (including school teachers) actively plan to return to topics again and again throughout the term. I’ve found that since different students have hugely varying learning cycles it can be hard to create a one-size-fits-all plan. For most, however, a weekly review with a student of the previous week’s school work can provide a huge boost to their long-term learning, and test scores towards the end of term.