The Spaced Repetition Party

So you’re at a party. It’s not some crazy kegger, it’s just one of those social mixers you go to every once in a while to meet people. A homely guy walks up to you and introduces himself as Craig. He’s a financial consultant. He soon moves on.

Photo by Wallie-The-Frog

A few minutes later, he walks up again, and asks, “Remember me?”

“Uhhh, Craig, right?” you reply.

“Yes,” he says. “And what do I do?”

“Uhhhh,” you say intelligently as you draw a blank.

“Financial consultant!” he says snippily and walks off.

A few minutes later he’s back again. He walks up to you and looks at you. “Hey, Craig the financial consultant,” you say. He nods and moves on.

He shows up again an hour later, and then one more time before the end of the event. He’s satisfied you know who he is.

The scene described above is a fictional dramatization of how spaced repetition works. Just like you forgot unmemorable Craig’s profession only 5 minutes after meeting him, you forget most things you learn. That is, unless you’re reminded. And it turns out that there are optimal times to be reminded, and that the more you’re reminded, the less often you need to be reminded. This is the “spacing” of “spaced repetition,” and its rules been pretty well figured out.

The famous Pimsleur language learning system is based on the principle of spaced repetition. It was designed for a time when static audio recordings were cutting edge, however, and the latest adaptation of the spaced repetition principle is spaced repetition software (SRS), which has been refined quite nicely in recent years by a Polish man named Piotr Wozniak.

With SRS, you “join the party” by starting up the software. You’re presented with various “cards” or “facts” which you want to remember. Some of them, like Craig, aren’t particularly memorable, and when they come up again, you may falter. No matter; SRS is infinitely patient. The more you have trouble with a fact, the more often it shows up in your review cycles, until eventually you get it down pat and it gets spaced out to the point where you hardly ever see it again.

Sound like fun? In my experience, the idea of efficiently offloading the work of memorization to a computer program tends to appeal mainly to programmers. I was introduced to it by programmer friend John Biesnecker, who was seduced by SRS evangelist and blogger Khatzumoto (also a programmer). I’ve seen another programmer friend, Mark Wilbur, go fanatical about SRS. Meanwhile, linguists and language teachers tend to go, “meh.”

Photo by Tom Lin

Personally, while I have my misgivings about SRS (a topic for another post), I think it’s a fantastic concept. The idea that, through science, we can understand how we forget, describe it in algorithms, and then systematically counteract it through software and learned behaviors is nothing short of amazing. The problem is that most of us aren’t willing to simply plug in and “trust the machine.” We prefer to live our lives unplugged… or at least not to be ritually spoon-fed our knowledge.

Like any innovative new form of technology, SRS has its early adopters. Those people swear by SRS, daily executing their spaced “reps” with the leading software: SuperMemo, Mnemosyne, and Anki. At the same time, though, something bigger is happening. Behind the scenes, SRS methods are infiltrating other learning software, such as Pleco (a popular Chinese dictionary). Although perhaps not completely obvious, SRS methods are a cornerstone of innovative Chinese character writing service Skritter. Cerego, the company behind another learning system earning lots of praise,, describes itself thusly:

> Based on years of applied research, Cerego has built adaptive, web-based applications that accelerate knowledge acquisition. Cerego’s patented core learning engine is driven by algorithms that generate optimal learning schedules for discrete chunks of declarative learning content, called “items”. This intelligent scheduling is achieved by gathering metadata on individual user performance and modeling memory decay patterns at the granular level of every item.

Guess what? It’s SRS.

The fact is, the average person doesn’t need to learn to change his habits to adapt SRS. As various companies and developers realize the value that SRS integration offers any kind of learning system, they’re integrating it into their existing products and services. It’s starting to appear in more and more products we already use. In the next few years, you can expect the slower ones to join the party as well. SRS is coming to you.


John Pasden

John is a Shanghai-based linguist and entrepreneur, founder of AllSet Learning.


  1. I’m a huge fan of SRS, whether it be used in Pimsleur, Michel Thomas (wonderful for latin languages) or software. I’ve used Anki over the last few months to go from perhaps 20 hanzi to around 1000, with only five minutes ‘effort’ in the morning and evenings. Of course we all learn most effectively in different ways, but I’d be very interested to know whether if the linguists who say meh gave it a go, they would find it as useful as I do.

    Any chance of integrating it into the Chinesepod flashcard system? This would be enough for me to spend the money on a subscription, having already donated to Anki for the effort that’s put in.

  2. Oops, SRS->SR in the above.

  3. So does Craig give you his business card at the end of the party? Advertising works on a similar principle called RR, or “repeated repetition” (grin).

    But on a serious note, thanks for bringing Skritter to my attention. It does look really good. For the practice of most language skills, it is easy to find opportunities in the real world (Character recognition? Try reading a newspaper. Listening comprehension? Try conversation) but writing characters is the one skill that is really difficult to practice in a meaningful way.

  4. I’ve never made much use of SRS for the same reason I never used flashcards — I’m basically a lazy, undisciplined learner. Anki and applications like that seem to be sort of like Getting Things Done systems — just great, if you’re the kind of person who can use them, but no good to people who can’t. Or at least me.

    Then again, the way I’ve learned without computer aids does roughly resemble SRS: I’ll read something, have to look up a character or word, and then either remember the character or word, or not remember it, get irritated with myself for not remembering it, and remember it the second or third time.

  5. Erick Garcia Says: August 6, 2009 at 9:41 pm

    I’ve been using Anki for a few months, and so far, its been amazing. I’ve been using it in conjunction with “Remembering the Hanzi” and it was worked wonders. I’m a Heisig/SRS evangelist as well, having done presentations for both Japanese and Chinese associations in college.

    Last semester in Chinese 202, a lot of the times many classmates would ask me how a character is written, and I would give it to them, almost like a “walking dictionary” and all thanks to crazy mnemonics and SRS!

    John, consider doing a chinesepod on these topics, or maybe intergrate them into the chinesepod process. I wonder what “Spaced repetition” in chinese is…

  6. I am a big fan of, partly because of their lists! They have great audio and example sentences. Couple that with SRS, and it couldn’t be easier/more fun to use.

    The one thing is that my writing has not improved like it should. How would you recommend using SRS for writing?

  7. Since I learned about SRS from John Biesnecker as well, and since he might be too shy to plug his new site, here’s a link to his most recent piece on SRS.

    Brendan, I could give you strong competition in the lazy-and-undisciplined category, esp. since I’m reading Pasden instead of reviewing Anki right now. But I do particularly like spaced repetition where I am right now — intermediate character/vocab learning — because I can’t (or am too lazy to) read in quantities large enough to get the repetition I really need.

  8. Mark Friedenbach Says: August 8, 2009 at 9:34 am

    John, I’d be very interested in hearing your misgivings about SRS that you allude to. I’ve been playing around with writing an SRS web application that nicely integrates SRS into a ChinesePod-like approach to language learning. Even been batting around the idea of pitching it to Praxis language if you guys are receptive. I think there’s A LOT to be gained, and its very compatible with their system.

  9. I’ve subscribed to Chinesepod on-and-off over the last few years. The “on” part because of the great raw content, the “off” part because it seems to be anti-systemic and anti-SRS in its basic structure. The lessons are independent modules with no layered relationship between them. The user has to fight and struggle to create layering and SRS of their own if they want to pursue this strategy.

    Adding to Jonathon’s comment – I think it would be great if Chinesepod would build SRS into its full content – the lesson content and sequencing in addition to the flashcards and other tools. It then would evolve from being a source of great raw content to a great learning system.

  10. I have to say I learned more from Pimsleur Chinese than I did when attending Xiamen university. That being said, it helped picturing pinyun when hearing the context, and that I did learn from university. I find Pimsleur combined with Chinesepod helped me quite a bit with my Chinese.

  11. […] week, John Pasden wrote an introduction to spaced repetition (you can read mine here). He and I don’t quite see eye to eye on the issue, so I thought […]

  12. John, I didn’t quite catch why you’re not a fan of spaced repetition? “Plugging into the machine” aside, wouldn’t it be equivalent to having a big stack of handmade flash cards, only a more efficient way of choosing which cards to study at a given time?

    I recently organized all my chinese cards from ChinesePod and elsewhere into a single deck with an SRS-based routine for choosing which cards to study. I’ve found that it helps ensure that old words don’t buried while still allowing me to add cards at a rapid pace.

  13. I’ve seen another programmer friend, Mark Wilbur, go fanatical about SRS. Meanwhile, linguists and language teachers tend to go, “meh.”

    Woah there, cap’n! I was a linguistics major and then Japanese major in school, and I’ve been exclusively employed as a language teacher or language school partner for the past 6 years! The last time I had a programming job was 9 years ago.

  14. Mark,

    And when was the last time you coded something? Once a coder, always a coder, I say… 🙂

    (Don’t worry, I don’t mean it as an insult!)

  15. Ryan,

    It’s not that I’m against repetition itself. I just am not crazy about a system with demanding behavioral modification requirements.

    I’m going to write about this more in the future.

  16. None taken. I’ll just have to remind you what my job is and then click away snippily!

    Seriously, though, I wasted so much time learning, forgetting and relearning Chinese at the beginning that it was almost enough to bring me to tears when I saw all my old notebooks from years ago filled with page after page of Chinese I’d been studying. Many of the exact same things noted in multiple notebooks that I’d used years apart. What spaced repetition has saved me from is reviewing a concept way too much for the first few weeks, forgetting to keep reviewing it a few months later and then starting over from scratch when I encounter the phrase a year later.

    My absolutely favorite way to learn vocabulary is by having lots of really, really understanding speakers of the language who will just bear with me until I understand what they’re saying. That worked great for Japanese when I was in school. Since I was helping them with English too, it turned out to be really mutually beneficial and a way to make some good friends, too. I still wish I’d had anki (and RTK) to help learn the written language, though.

  17. If you like spaced repetition for language learning, come visit us at and check out our online foreign language learning software.

    We have focused on making it super easy to use. If anyone says they saw it on this bog, just tell us and we will set you up with a user name and password free.

    We need the feedback of people who have used other spaced repetition programs.

  18. Sorry, I don’t know how many times I have spelled language incorrectly.

    The correct URL is

    My apologies. But the incorrect one will work too because we have that URL being re-directed to the right one.

  19. John, I agree that you don’t need spaced repetition to learn things. People have been learning for centuries without it. But it does make things easier, so people really should try it.

    Doesn’t have to be a big thing. For example, simply choosing Anki over another flashcard system that doesn’t use spaced-repetition is already a great start.

    Similarly, when I’m learning 20 hanzi a day, I will start revising yesterday’s words. Then in a week I will revise the entire week’s. Then after a month … Each period gets longer, and I seem to get reminded just as I’m forgetting 🙂

  20. I learned conversational French using the excellent Assimil course, which consists of a daily lesson. For the first 50 days, the lesson is simply listening, with a handful of fill-in-the-blank exercises. For the next ~75 days, you continue to listen to new material. But you also go back to the beginning, and translate English -> French, starting with lesson 1. Figure 20 minutes / day at first, rising to 40 minutes, for about 120 days total.

    At the end of this, I was far enough along to have rudimentary conversations with French/English speakers, and to rely on those conversations for further learning.

    I mention this because because I think the Assimil courses are actually built around some sort of spaced repetition. Doing them daily, I would often come back to some previously-covered topic right about the time it was getting a little fuzzy. I don’t know if this is true, but in any case, I’m now able to carry on conversations with native French speakers for 20 minutes to an hour after less than 2 years of regular (but not hugely intensive) study.

  21. Loopy Frisbee Says: March 29, 2010 at 8:25 pm

    I have been using Supermemo for the past 4 years, and I have nearly 40,000 flashcards full of Japanese, Chinese and various other information. My Japanese is fluent and I’m making steady progress in Chinese. SRS isn’t the answer to everything, but it is the best way to preserve learning progress over time (Provided you have the motivation to use it every day). It is an autodidact’s dream.

  22. […] saw this great video on SRS (spaced repetition system/software), which provides an illuminating visual […]

  23. […] app also has its own built-in SRS functionality. I didn’t test this functionality much, as the app seemed much more suited to a […]

  24. MEMORY IN CHINA – vs. elsewhere. John, I’m wondering if you’ve observed how Chinese students memorize things. Do they do any kind of “SRS” type memorizing? The closest I came to ever having to memorize anything was for spelling tests in high school and for SATs. I ask because many friends ask me how their kids can best “learn English.” What they really mean, is how can their kids improve on their English tests. While an SRS approach is not “my” preferred method for acquiring vocabulary, is it quite appropriate for these kids? For example, I can’t tell them to read a lot of books in English, because to be honest, they’re not so widely available around here, etc., etc. I wonder about this, as in other subjects the kids are memory mavens. What is it about memorizing something in another language that muddles up the mind?

  25. Actually, there is a SRS software 100% geared toward learning Chinese vocabulary. Even better, it is free.

    Pingrid combines characters, pinyin, English translation, pronunciation and handwriting wrapped up in one memory game.

    Check it out at:

  26. […] days, and it has a lot of potential. Basically, “Learn Mode” is FluentU’s take on SRS, an idea which isn’t so great all by itself, but holds a lot of promise for enhancing other […]

  27. […] of my AllSet Learning clients use Pleco or Anki to review vocabulary. Both has built-in SRS flashcard functionality, so doing occasional reviews pretty much solves that problem, right? Well, […]

  28. […] Earlier this year the Global Times did an article on using SRS (spaced repetition software) technology to “Learn Chinese in a flash.” The journalist interviewed both me and Dr. Orlando Kelm about the issue, but most of what we said didn’t actually make it into the article. I’m going to use the content of that exchange to finally address my misgivings about SRS. […]

  29. I have been visiting your blog throughout my Chinese language learning journey – I find it a really useful resource and have provided a link to your site on my blog here:

  30. […] The Spaced Repetition Party […]

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