QS Resource Page: Spaced Repetition and Learning


Using typical methods, it is laborious and frustrating to memorize vocabulary, formulas, and facts. So we may feel discouragement when thinking about trying to learn something that requires a first step of deliberate memorization. This is unfortunate, because memorization doesn’t have to be hard.

How Spaced Repetition Works (A graph)

Methods to quickly and efficiently memorize using “spaced repetition” has been known to experimental psychology for a hundred years, and convenient tools to take advantage of fast memorization techniques have been around since Piotr Wozniak began developing his Supermemo software in the early 1980s. Many of us in the Quantified Self use these tools. We’ve put together this page to list resources, share experiences, and invite comments and questions. We hope you find it useful. If you do, please contribute some  knowledge or questions to the comments.

Below you’ll find the following sections:

  • The Basic Idea Behind Spaced Repetition
  • Learning Chinese with Spaced Repetition
  • Winning Jeopardy with Spaced Repetition
  • Using Spaced Repetition to Build General Knowledge and Curiosity
  • Using Spaced Repetition as a Cognitive Assay
  • The Value and Limits of “Well-Formulated Knowledge” (i.e. good flashcards)
  • List of Spaced Repetition Software Tools
  • Academic References on Spaced Repetition

The Basic Idea Behind Spaced Repetition

Spaced repetition is based on the insight that there is an ideal moment to practice what you’ve learned. Practice too soon and you waste your time. Practice too late and you’ve forgotten the material and have to relearn it. The right time to practice is just at the moment you’re about to forget. If you are using a computer to practice, a spaced repetition program can predict when you are likely to forget an item, and schedule it on the right day. (For more, see this story about Piotr Wozniak and Supermemo in Wired.)

In the graph above, you can see how successive reminders change the shape of the forgetting curve. That is, with each well-timed practice, you extend the time before your next practice. Spaced repetition software tracks your practice history, and schedules each review at the right time.

Learning Chinese With Spaced Repetition

Spaced repetition is frequently used to quickly gain vocabulary in a foreign language. In this talk from a 2012 Bay Area QS Show&Tell, Jeremy Howard describes his experience learning Chinese.

Winning Jeopardy With Spaced Repetition

Roger Craig holds the all time record for single day winnings in Jeopardy. In this video, he describes his training method, which included the spaced repetition software Anki.

Using Spaced Repetition to Build General Knowledge and Curiosity

At the Portland Quantified Self Show&Tell, Steven Jonas presented a fascinating project that involved the use of spaced repetition to build general knowledge and stimulate curiosity. We hope to have a video of this talk up soon. For now, here’s a brief summary: Steven has many learning projects going, but of special interest is his discovery that memorizing seemingly trivial information caused a large improvement in his life. Using a Supermemo “deck” of 613 flashcards, he quickly learned the location and capital of every country. He found that having a simple, even primitive framework of knowledge made international news more accessible and interesting. For instance, when he saw a  report about the Taureg rebellion in Mali, he didn’t skip over it as something unrelated to his picture of the world, but instead read it with interest, connecting his knowledge of where Mali was and what it’s capital was called to new information from the news. He found that his overall style of reading, conversing, and learning improved a lot. This was unexpected. It shows that the  value of memorization is not in the mere knowledge on the cards, but in the establishment of a mental structure upon which new thoughts and knowledge can develop.

Using Spaced Repetition as a Cognitive Assay

Nick Winter is the author of a popular Chinese and Japanese learning program called Skritter, which includes spaced repetition as a key feature.  Here are the slides from a Quantified Self Show&Tell talk by Nick in which he discusses how spaced repetition practice can be used as a reliable cognitive assay; that is, a test of how well the brain is functioning. Because spaced repetition practice tends to be of consistent difficulty, patterns in our performance can offer clues about what makes us more or less able to learn.

The Value and Limits of “Well-Formulated Knowledge” (i.e. good flashcards)

This is a bit of an advanced topic, but I mention here to stimulate interest and comments; do add your thoughts if you have something interesting on this. Piotr Wozniak has a long section on his web site called Effective learning: Twenty rules of formulating knowledge. There are many tricks here. But note the first rule: Do not learn if you do not understand. He offers the rather hilarious example that it is possible, using Supermemo, to memorize a textbook on German history in German, even if you know no German. Possible, yes, but also stupid and useless. Spaced repetition helps directly with one facet of learning only: memorization. Learning involves other things too. Steven Jonas talk about the value of “trivial” information demonstrates; we’re still discovering different ways to make spaced repetition valuable in the larger context of learning. We’re interested in your experiences.

Spaced Repetition Software Tools in Common Use

This is a shorter list than you will see in the Wikipedia entry on spaced repetition. That’s because it includes only tools that we know to be in use by people who have mentioned it to us. If you are using something actively, and are willing to share your experience, please let us know.

  • Anki – Widely used and in active development. Open source. Desktop and Android versions are free. iPhone version is $17.50.
  • Mnemosyne – Also open source; runs on Windows/Mac OS, with card review possible on Android and Blackberry mobiles. All versions are free.
  • Skritter – Chinese and Japanese only. Looks great and is written by a good QS friend (see Nick Winter’s talk, above), but I don’t learn these languages so I await your reports. Subscription: $9.95/month.
  • SuperMemo – The original; still widely used. There are some licensed versions on other platforms, but the main line of development is Windows only. ($60)

Academic References on Spaced Repetition

A good place to begin is with Piotr Wozniak’s General principles of SuperMemo, which has many links to deeper explanations of his software, experience, and research. Here are some additional sources. (You are welcome to contribute, too. Add references in comments for now, and I’ll go back and incorporate them into this list.) Most of these are readable without specialized knowledge.

  • Appleton Knapp, S. L., Bjork, R. A., & Wickens, T. D. (2005). Examining the spacing effect in advertising: Encoding variability, retrieval processes, and their interaction. Journal of Consumer Research, 32(2), 266–276.
  • Bahrick, H. P. (1979). Maintenance of knowledge: Questions about memory we forgot to ask. Journal of Experimental Psychology: General, 108(3), 296.
  • Bahrick, H. P. (1984). Semantic memory content in permastore: fifty years of memory for Spanish learned in school. Journal of Experimental Psychology: General, 113(1), 1.
  • Bahrick, H. P. (1985). Associationism and the Ebbinghaus legacy. Journal of Experimental Psychology: Learning, Memory, and Cognition, 11(3), 439.
  • Bahrick, H. P., & Phelphs, E. (1987). Retention of Spanish vocabulary over 8 years. Journal of Experimental Psychology: Learning, Memory, and Cognition, 13(2), 344.
  • Bjork, E. L., & Bjork, R. A. (2003). Intentional forgetting can increase, not decrease, residual influences of to-be-forgotten information. Journal of Experimental Psychology: Learning, Memory, and Cognition, 29(4), 524–531. doi:10.1037/0278-7393.29.4.524
  • Bjork, R. A. (2001). Recency and Recovery in Human Memory. In The nature of remembering: Essays in honor of Robert G. Crowder. American Psychological Association. doi:10.1037/10394-011
  • Bjork, R. A., & Bjork, E. L. (1992). A new theory of disuse and an old theory of stimulus fluctuation. From Learning -rocesses to ognitive processes: Essays in honor of William K. Estes, 2, 35–67.
  • Bjork, R. A., & Bjork, E. L. (2006). Optimizing treatment and instruction: Implications of a new theory of disuse. Memory and society: Psychological perspectives, 116–140.
  • Bjork, R., & Richardson-Klavehn, A. (2002). Memory, Long-term. In Encyclopedia of cognitive science (Vol. 2, pp. 1096–1105). London: Nature Publishing.
  • Dudukovic, N. M., & Wagner, A. D. (2006). Attending to Remember and Remembering to Attend. Neuron, 49(6), 784–787. doi:10.1016/j.neuron.2006.03.008
  • Grote, M. G. (1995). The Effect of Massed Versus Spaced Practice on Retention and Problem-Solving in High School Physics. Ohio Journal of Science, 95(3), 243–247.
  • Landauer, T., & Bjork, R. (1978). Optimal Rehearsal Patterns and Name Learning. In M. Brunebert, P. Morris, & R. Sykes (Eds.), Practical Aspects of Memory (pp. 625–632). London: Academic Press.
  • Mozer, M. C., Howe, M., & Pashler, H. (2004). Using testing to enhance learning: A comparison of two hypotheses. Proceedings of the 26th Annual Conference of the Cognitive Science Society, 975–980.
  • Pyle, W. (1913). Economical learning. Journal of Educational Psychology, 4(3), 148.
  • Traxel, W. (1985). Hermann Ebbinghaus: In memoriam. History of Psychology Newsletter, 17, 37–41.
  • Wagner, A. D., & Davachi, L. (2001). Cognitive neuroscience: forgetting of things past. Current Biology, 11(23), R964–R967.

One Response to QS Resource Page: Spaced Repetition and Learning

  1. LittleFish says:

    I’ve been using SuperMemo for the past six years, and I use it for anything I wish to remember. It began with just languages, and now it has extended to almost every aspect of my intellectual life.

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