In short, Spaced Repetition = testing + time. You test yourself on a fact repeatedly, spacing out your repetitions over time. (But won't this take forever? Ah, as we'll see later, there's a trick...)

Spaced Repetition

In short, Spaced Repetition = testing + time.

You test yourself on a fact repeatedly, spacing out your repetitions over time. (But won’t this take forever? Ah, as we’ll see later, there’s a trick…) Spaced Repetition is free, evidence-based, and so simple you can do it with a shoebox.

How To Remember Anything Forever-ish

Our favorite introduction to spaced repetition is this comic by Nicky Case.

In short, Spaced Repetition = testing + time. You test yourself on a fact repeatedly, spacing out your repetitions over time. (But won't this take forever? Ah, as we'll see later, there's a trick...)

Also, throughout this comic, you can test yourself on what you’ve learnt, at spaced-out intervals. That is: you’ll use Spaced Repetition to learn about Spaced Repetition.

How To Remember Anything Forever-ish
How to Study for Exams – Spaced Repetition | Evidence-based revision tips

The critical advancements are in how future text is structured and used. Furthering the development of non-linear text organized in associative ontologies with built-in spaced repetition mnemonics will undoubtedly enable new forms of text-based thinking. It’s evident how these tools will expand our cognitive capabilities. It’s much less clear how they will enhance our ability to develop wisdom. Perhaps, then, the future of text should be guided by one more domain in addition to cognitive science, neuroscience, and psychology: philosophy.

Matter-Energy Metapattern Hyperliteracy | by Wesley Finck | Medium

Intermittent repetition can keep old ideas active in students’ minds until they’re ready to engage. Rather than delivering a bound monograph on meditation, instructors can slowly unfurl an idea over hundreds of days. Critically, these apps are a mass medium, just as books are: lessons can be “written” once and redistributed cheaply to huge audiences. Could this approach be applied more generally?

To engage with a book’s ideas over time, readers must remember its details, and that’s already a challenge. One promising solution lies in spaced repetition memory systems, which allow users to retain large quantities of knowledge reliably and efficiently. Like meditation, these systems involve a daily practice: every day, a reader maintains their memory library by reviewing a few dozen lightweight prompts. Each prompt asks a detailed question, like “What types of stimuli does George Miller’s span of absolute judgment describe?” Each day’s session is different because each prompt repeats on its own schedule. When a user remembers or forgets the answer to a prompt, the system expands or contracts that prompt’s repetition interval along an exponential curve. These expanding intervals allow readers to maintain a collection of thousands of prompts while reviewing only a few dozen each day. Practitioners generally complete their review sessions in moments which would otherwise go unused, like when waiting in line.

Timeful Texts — Future of Text Volume 1

The most common mechanism of change for spaced repetition learning tasks is called retrieval practice. In brief: when you attempt to recall some knowledge from memory, the act of retrieval tends to reinforce those memories.For more background, see Roediger and Karpicke, The Power of Testing Memory(2006). Gwern Branwen’s article on spaced repetition is a good popular overview. You’ll forget that knowledge more slowly. With a few retrievals strategically spaced over time, you can effectively halt forgetting. The physical mechanisms are not yet understood, but hundreds of cognitive scientists have explored this effect experimentally, reproducing the central findings across various subjects, knowledge types (factual, conceptual, procedural, motor), and testing modalities (multiple choice, short answer, oral examination).

The value of fluent recall isn’t just in memorizing facts. Many of these experiments tested students not with parroted memory questions but by asking them to make inferences, draw concept mapsSee e.g. Karpicke and Blunt, Retrieval Practice Produces More Learning than Elaborative Studying with Concept Mapping (2011); and Blunt and Karpicke, Learning With Retrieval-Based Concept Mapping (2014)., or answer open-ended questions. In these studies, improved recall translated into improved general understanding and problem-solving ability.

Retrieval is the key element which distinguishes this effective mode of practice from typical study habits. Simply reminding yourself of material (for instance by re-reading it) yields much weaker memory and problem-solving performance. The learning produced by retrieval is called the “testing effect” because it occurs when you explicitly test yourself, reaching within to recall some knowledge from the tangle of your mind. Such tests look like typical school exams, but in some sense they’re the opposite: retrieval practice is about testing your knowledge to produce learning, rather than to assess learning.

Spaced repetition systems are designed to facilitate this effect. If you want prompts to reinforce your understanding of some topic, you must learn to write prompts which collectively invoke retrieval practice of all the key details.

How to write good prompts: using spaced repetition to create understanding

Most spaced repetition software has a special function which can rapidly generate sets of fill-in-the-blank prompts like this. In the software interfaces, these prompts are often called “cloze deletions.” In each review session, the software will only ask you to fill in one blank. This behavior is important because without it, one variant would “give away” the answer to another.

How to write good prompts: using spaced repetition to create understanding

Mastery is our term for the one-two punch of active recall and spaced repetition applied to the notes and highlights you take while reading. Used together, these principles of cognitive science enable you to retain substantially more of what you read with significantly less effort.

As a more everyday alternative, you can also employ a deceptively simple technique known as cloze deletion. With cloze deletion, a salient keyword or keyphrase is hidden from the passage, giving you an opportunity to pause and consider the missing word.

Cloze deletion is, of course, just a fancy way of saying fill-in-the-blank. This might seem a trivial tweak, but the simple act of hiding a word forces you to consider the surrounding context and search your mind for an answer. The hidden word itself isn’t that important; it’s the modest effort of being forced to think about what you’d otherwise passively read.

Spaced repetition is a technique for spacing out of reviews of previously learned material according to an algorithm designed to optimize your limited time for review. Each time you review a piece of information, you supply feedback to that algorithm which estimates the optimal time to show you that information again.

Without getting too technical, if you deeply understand something, you don’t need to be reminded of it that often whereas if you struggle with something, you need to be reminded of it more often. Further, each time you successfully recall something, your memory of that thing is strengthened, so the intervals between successive reviews become longer and longer.

Spaced repetition is the literal opposite of cramming which, we probably don’t have to tell you, is a great way of passing a test but a terrible way of truly learning something.

Using Spaced Repetition and Active Recall with Books to Hack Your Brain

For example, you can use spaced repetition to augment creativity by priming your awareness with inchoate thoughts, slow hunches, and unanswered questions. Or you can use spaced repetition to write an article, as I did with this very article you’re reading (made possible by Themed Reviews), by quickly jotting down nonlinear thoughts and progressively editing standalone paragraphs for clarity.

Adding Intention to Spaced Repetition

Further reading,