Introduction

Throughout this article, I assume that the reader is somewhat familiar with spaced repetition[1]. If not, here’s a brief introduction. Spaced repetition is a learning technique that allows the learner to remember things for many years. It’s quite simple, and it incorporates increasing intervals of time between subsequent repetitions of the material.

Beating the forgetting curve with spaced repetition

The most common implementation nowadays is flashcard software. It works like this. You create a flashcard consisting of a question and an answer to it. The next day the app asks you this question. If your answer is correct, it will ask you this question with increasing intervals. For example, in 1 week, in 3 weeks, in 2 months and so on. The most well-known apps are probably Anki and SuperMemo.

Multiple scientific studies show that spaced repetition works. Moreover, it works very well. It’s been almost a century since we discovered spaced repetition. One would expect that this technique is widely adopted in education. The reality is that it found only niche applications so far. Why is that? Here I want to share my thoughts regarding this question and propose a possible solution.

Why spaced repetition has not taken off (yet)

There is an obvious problem with spaced repetition. It’s quite tiresome to make your own questions and answers for every single thing you need to remember. On the one hand, to make a question and an answer you have to retell what you’ve just read in your own words. The consensus is that retelling the material in your own words is quite beneficial for understanding. However, what’s the use in these benefits if it’s too hard for most people to do? SuperMemo usage statistics suggest that only about 1% of those who try to use it continues to do so regularly[2]. I conducted some personal interviews regarding spaced repetition and learning in general. Several people said outright that it seems too hard to make the questions of their own. So they won’t do it. On the other hand, they also said that if the questions were ready-made, they would try to use them. All of this gives us a hint that to make spaced repetition mainstream, we have to provide most people with already existing question-answer pairs.

Let’s look at the existing solutions. Spaced repetition is used in many language learning apps. The solution they offer is ready-made flashcards. You don’t have to make your own questions. Problem solved.

With Quizlet people can easily share their flashcard decks. It claims to use a variation of the spaced repetition algorithm. However, since it’s optimized for cramming, it’s not well optimized for long-term retention.

Medical students use Anki and share their decks among themselves. There is even a subreddit devoted to sharing medical decks /r/medicalschoolanki, and it has 18k members as of now. I’m not a medical student. I tried to read those decks. It feels like reading a random set of facts. So I don’t think I can learn from those much (in contrast to textbooks and scientific articles). Trying to practice from those decks in Anki would be like jumping into water before learning to swim. However, it’s crucial for doctors to be able to remember large amounts of information. Students use those decks with success. Therefore it should work to some extent.

Knowledge Transfer

But we know that we can transfer knowledge from one person to another. How do we do it? We read books. We read articles. We listen to lectures. Unfortunately, all of those are terrible at actually making you remember the things they have to say.

What are the main differences between a book and a flashcard deck? What makes a book so good at transferring knowledge? And what makes a flashcard deck so good at retaining knowledge in one’s mind?

While it’s obvious why a flashcard deck is so good, it’s not obvious why a book or an online course works. Books and online courses come in different shapes and forms. So it’s hard to pinpoint the reason they work so well (at least sometimes). But it seems that there are at least two universal features. One is telling a story meaning that it resembles a person talking to you and explaining something. The other is the fact they all have a structure.

Now we can see that a flashcard deck usually lacks the two universal features of a book. It doesn’t tell you much on its own. It doesn’t explain the thing it’s testing. And it doesn’t have the structure a book usually has.

The most trivial solution is an Anki deck created by the author of a book or an online course. You take a course. Then you answer the questions from an Anki deck as a kind of an exam. But it seems that in most cases this scenario is too complicated for people to use.

The Solution

OK, what is the solution I’m trying to propose? It’s the structure plus flashcards, all in one place. You have an online course divided into sections. Each section looks like an article or a document. But throughout this article, flashcards could be inserted right into the text. Now instead of a simple deck, you have a full course with flashcards placed at appropriate places throughout the course.