How to remember anything, forever
Posted on 01-03-2020
Recently, I started flicking through a book I’d read about ten years ago, Juliet Gardiner’s The Thirties: An Intimate History. I stumbled across the section on education, and was quickly engrossed. But the weird thing was that I had no recollection of ever having read these pages before. And yet, the book was clearly well-read, and even had a folded page at this particular section.
I am not the only one. I spoke to one author who said that he’d forgotten most of the detail in a book he’d actually written ten years ago. The psychologist BF Skinner said that ‘One of the most disheartening experiences of old age is discovering that a point you just made—so significant, so beautifully expressed—was made by you in something you published long ago.’ There’s a concept in psychology called cryptomnesia, which is when you think you’ve come up with a brand-new idea of your own, when in fact it can be shown that you encountered the idea before.
Teachers will also be familiar with something similar in the classroom: students who totally understand simultaneous equations, say, at the end of one lesson, but then stare blankly when they are mentioned at start of the next one.
Technology offers a brilliantly simple way to solve all of these memory problems: spaced-repetition algorithms. To remember something for the long-term, we need to encounter it more than once. However, the gaps between those encounters matter too, and this is where most traditional revision goes wrong. Spending hours revising just before an exam doesn’t help you remember for the long-term: you need to space the practice out. This is one of the oldest findings in psychological research, based on Hermann Ebbinghaus’s experiments in the 1890s.
However, it’s always been quite hard and fiddly to implement. It’s tricky to know exactly when you should be reviewing everything, and the right review schedule will vary depending on your confidence with the material. This is where the spaced-repetition algorithms work their magic. They will do all the tedious leg-work of deciding on the best moment for you to review the content.
I now use a flashcard app called Anki to try and prevent forgetting what I’ve read. I’ll highlight sections of a book that I think are of interest, and then, when I have finished reading the book, I’ll turn them into individual flashcards in Anki. Then, if I spend 5-10 minutes each day reviewing the flashcards, the spaced-repetition algorithm will show me cards from books I’ve read months or even years ago.
Spaced-repetition algorithms are a part of many education apps. Used well, they can also be a way of breaking down the silos between different phases, years, topics and subjects. Imagine a Year 7 student who has their own personalised flashcard library reminding them of important content from year 6, or the English student who is studying a novel unit in class, and is presented with a flashcard about the poetry they did the term before. Spaced-repetition algorithms promote memory, and they also promote one of the most under-appreciated by-products of memory: the ability to make connections between different ideas.
Further reading & watching
- My new book, Teachers vs Tech, discusses this research at length in chapter 4
- You can watch a researchEdHome video of me discussing this, here.
- This follow-up blog looks at the secret history of spaced repetition systems
- This follow up blog looks at how to design good flashcards