With the help of the LessWrong.com team, we've set up a way for you to embed flashcard quizzes directly in your LessWrong posts! This means that you can write flashcards for any of your LessWrong posts and either: 

(a) quiz people as they read your article to help them retain your content, or 

(b) provide an easy way for them to continue to be quizzed after they are done reading so that they can indefinitely remember the most important things they learned in your article!

Note that while many people think of flashcards as being just for facts and definitions, this is far from the truth! I personally use flashcards/spaced repetition daily for complex concepts, connections between ideas, ways of thinking about a problem, patterns, takeaways, strategies, arguments, triggers I want to associate with specific behavior, and so on.

This post will explain how to add flashcards to your own posts in a step-by-step fashion.

If you want to see an example of a LessWrong post with flashcards, check out my LessWrong post on self-control, where we first experimented with this feature.

And before we get to the instructions, here's an example (from that same post) of what embedded flashcards look like when you put them right in your article:


Adding flashcards to your post is quite simple. Just follow these steps:


Step 1: Create your own deck of flashcards using Thought Saver

Create a Thought Saver account at app.thoughtsaver.com and use it to create some flashcards for your post. You'll need to put all the flashcards for your post into the same deck. Here’s how to do that:

(i) Click “New Card” in Thought Saver to start creating a new flashcard - but don’t save it just yet.

(ii) In the text input box with the label "Decks"...

  1. Type the name of the new deck you'd like to create for your article.
  2. Hit "Enter" ("Return") or click "Create new deck".
  3. This card has now been added to that deck, and this deck will now be available so that you can add all the other flashcards (for your post) to it too!



  • Type "Book summary: The Very Hungry Caterpillar."
  • Click 'Create new deck: "Book summary: The Very Hungry Caterpillar."'
  • Repeat these steps until you’ve created all flashcards for your article and added them all to this same deck.

Step 2: Go to the Thought Saver page for your new deck

(You’re ready to take this step once you've created all the flashcards for your article and added them to the same deck.)

(i) Navigate to the page for your deck by clicking the name of your deck on one of your flashcards:

Or alternatively, you can access a deck from the search bar by clicking in the search bar and then clicking the deck name when it appears:


(ii) Now set the order of the cards in your deck, so that they appear in the order that you'd like to quiz the reader on them. Click the overflow menu in the top right corner of the page (the 3 vertical dots). Click "Sort". Arrange the cards in the order you want. Users of your deck will be quizzed on the first card first, then the second card, and so on. This allows you to design your cards in such a way that the concepts built on each other. Click "Save" when you’re done sorting.



(Please note that the actual text/verbiage may vary from this screenshot as we are actively iterating on this wording to make this section more understandable.) 


IMPORTANT NOTE: The following steps will have to be repeated for each widget/quiz you’d like to embed in your article. We recommend including at least 2 quiz widgets in your article, but for a longer article, you may want to include more.

Step 4: Select which cards from your deck you would like to appear in the quiz for your (first) embedded widget 

If you're embedding multiple widgets in your article, we’ll assume that you want to have each widget show different cards (as opposed to certain cards from your deck being repeated in more than one widget). 

(i) Enter the appropriate ‘starting card number’ and ‘ending card number’ (based on how you sorted the cards in this deck previously). So for instance, if the starting card number is 3 and the ending card number is 7, that quiz widget will quiz the reader on cards 3 through 7.



(ii) Click “Copy” to copy the embed source URL to your clipboard:

IMPORTANT NOTE: you’ll need to have this URL copied to your clipboard for the steps below.

Example of how to spread the cards from your deck over multiple quizzes: 

  • You might choose to put the first card through the fifth card [cards 1–5] from your deck in the first flashcard quiz of your LessWrong post
  • And then in the next flashcard quiz, you might include cards 6–10, etc., etc.)
  • Note that from all embedded widgets, at the end of completing that quiz, users will have the option to subscribe to the full deck in Thought Saver (where they can get daily email quizzes, quiz themselves manually, create their own decks, etc.)

Note also that instead of (or in addition to) embedding a quiz, you can also just add a link to your flashcard deck by using the Share link feature (see screenshot above). For instance, at the bottom of your post, you could say "Click here to subscribe to the flashcards for this post" and have that text link to the share link.

Step 5: Create a new post on LessWrong or open one you’re currently working on then click "Edit Block"  within your post

If you’re not logged in to your LessWrong account, or if you do not yet have an account, log in or create an account first

Once you're logged in, open the post you are working on, or create your new post.

When you've reached a point in your post when you'd like to embed a Thought Saver flashcard quiz widget, click the "Edit Block" button to the left of the current line: 

NOTE: if you’re starting from a completely blank page, start typing something to make the “Edit Block” button appear or hover your mouse over the area just to the left of the current line you're on.

Step 6. Click "Insert Media" from the options menu


Step 7: Paste the embed URL you copied from Thought Saver, and click Save! 

Now you've successfully embedded a Thought Saver flashcard quiz into your LessWrong post! 

You may now continue writing your LessWrong post and repeating steps 4 through 7 to keep embedding more flashcard quizzes throughout that same post (as many as you'd like). 

We hope you enjoy this new functionality! We'd love to hear your feedback on it and on Thought Saver more generally! Please give us feedback by commenting below, or by clicking the feedback button in the upper right-hand corner of the Thought Saver app.

If you're interested in how to write great flashcards, I'd recommend Andy Matuschak's article how to write good prompts: using spaced repetition to create understanding. Andy and his collaborator Michael Nielsen have been the pioneers in this space of embedding flashcards in essays. I highly recommend their essay Quantum Country where they introduced this medium. You may also want to check out Andy's other work related to this topic.




New Comment
25 comments, sorted by Click to highlight new comments since: Today at 4:54 PM

Registering my continued dislike for dedicating effort on this feature (I voiced similar complaints when this was originally floated). My reasons:

  • retaining knowledge via spaced repetition is a poor fit for most of the posts on LW
  • the general advice is that using cards written by others is much less useful than cards you write yourself
  • nudges LW towards encouraging posts that are more amenable to space repetition, which I expect will marginally decrease other kinds of content
    • implicit in this is an argument that LW would be marginally worse if it spent more time on teaching things that you can learn by remembering them and less time on other things, like working towards reducing confusion about things we are currently confused about

When I originally floated the idea on Facebook, I was considering implementing it as an LW feature directly, which would've been a lot of effort. Then it turned out ThoughtSaver was already building it, with cross-site integration in mind. The actual implementation on LessWrong works the same way as the Metaculus and Elicit integrations we already had, and took less than an hour on our end. (Much more than an hour of effort on ThoughtSaver's end, obvciously, but amortized across more applications than just LessWrong integration, and that part of the effort didn't come from the LessWrong team.)

Fair enough, though I disagree with these points. For one thing, this feature already works, so I don't expect it will take any significant amount of time from the LessWrong dev team. 

But to respond to your more specific points, from my perspective:

(1) there is a common misconception that flashcards and/or spaced repetition is mainly useful for facts and definitions. It is also very useful for concepts ("a generative adversarial network is..."), takeaways (e.g., "the most important three points this post makes are..."), connections between ideas ("X and Y are thought to be different but they are connected through Z..."), strategies ("Here's a process you can use..."), and so on. I certainly don't think all LessWrong posts are suitable for this, but I think you're underestimating how many are. My guess is it is a good fit for 5%-20% of posts but that's a super rough estimate. I personally use flashcards for complex concepts all the time, including plenty I've created for myself from LessWrong and Slatestar Codex posts.


(2) indeed it is a standard belief that if you pick up someone's random flashcard deck that they wrote for themself you are unlikely to get much out of it (I agree with this too). That is different from a deck written specifically by the author for an essay (almost nobody has experience with this, other than through the experiments I link to in the bottom of the post) so the "I can't pick up my friend's deck" argument doesn't have much weight in this case in my view.


(3) I would argue that even posts that e.g., "work towards reducing confusion about things we are currently confused about" have takeaways that are worth remembering (e..g, "what should you think about differently having read the post?", "what was the approach of reducing the confusion?", "what is a useful analogy for thinking about this topic?", etc.)

These are all quite reasonable, and I'm pretty open to the idea that I'm mistaken and anchoring too much on the fact that I didn't find flash cards for spaced repetition useful, which might ultimately bias how heavily I weight things or assess the likelihood that flashcards would be helpful.

The process of making a piece of knowledge suitable for space repetition is a lot about making the piece of knowledge as clear as possible. 

When it comes to my own writing, I don't think it discourages me to write about ideas I believe are worth writing about that this new feature exists. I might find it interesting to experiment with a new way of writing posts and use the feature, but I don't believe that this is zero-sum. 

Asking "Is this likely to be useful?" is the wrong question. I think it's better to ask: "Is this an experiment that has the potential to produce something useful for the art of rationality?"

Trying out new ways to represent knowledge about the art of rationality has the potential to lead to progress and is thus worth doing. We shouldn't try to focus on one approach of gathering knowledge about rationality but try many.

The general advice is that using cards written by others is much less useful than cards you write yourself

As someone who has used SRS on a regular basis for multiple years, I disagree with this. Sure, there are times when my best option is to hand-craft cards for myself, but this is usually a function of there not already existing high quality cards that test me on the things I want to learn. Creating cards is useful for allowing me to focus on exactly the facts that I want to learn; the other times where this is true is when I have a specific model and vocabulary for understanding a field that isn't standard; there, creating cards allows me to target the specific vocabulary and ontology that is unique to me.

However, often times I want to learn something that doesn't meet these criteria: things that I can easily think about using a standard ontology and vocabulary, and are common enough subjects that someone has already taken the effort to make a sufficiently high-quality deck. In this case, making my own cards is just a waste of my time (and the time that is wasted isn't negligible; I've spent up to an hour on multiple occasions creating cards for domains that could just as easily been downloaded if I knew of a high quality deck that already existed). I'm using premade decks for learning pronunciation and meanings of Japanese Kanji and for mapping flags to the countries they represent. There are many subjects where I have cards I made myself that I would be just as well off using equally high quality cards made by another person, and others would be well-served using the same cards I made: learning the pronunciation and meanings of Russian words, mapping coordinates to the cities they locate, memorizing poetry, mapping astronomical symbols to the bodies they represent. Even in the case of mathematical definitions and associations, while the cards I use are tailored to me, similar cards could certainly be made that would be suited to a much wider audience, that would be nearly just as useful as the cards I actually use.

I'd estimate about 2/3rds of the cards in my Anki deck are too specific to me to have been mass produced, but the other 1/3rd would be very well justified in having been made with the intention of being able to be used by others, and that ratio could be even higher (maybe up to 2/3rds mass produceable) without causing problems.

  • the general advice is that using cards written by others is much less useful than cards you write yourself

Seems like using cards by others is still better than not using any cards at all?

There's an opportunity cost. If you spend a lot of time memorizing cards that don't really fit into your map of the world that costs a lot of time.

Can't wait for this book summary! It's a very rad read for rationalists indeed!

But in all seriousness, I'm excited to see what neat new posts will utilize this, and I'm curious to know how this might impact writers who are trying to think of ways to provide their readers with a great takeaway. ("Something to remember me by" haha) 

For me, I'm already thinking about how to write the flashcards for a post in such a way that each key thought might be somewhat independent on its own yet containing enough context to relate it back to the collection of thoughts that map/model the ideas behind a single post/concept. If I were to encounter one flashcard from the post's deck in a year from now, would I then easily recollect the entire post and its most important thoughts? I like the framework of thinking of each post as having one correlated deck of flashcards, and each key idea within that post correlating to one flashcard. The flashcard deck can represent a graph/network of thoughts that you want to remember "forever", and hopefully if you encounter any "node" (i.e. a flashcard) from that graph (i.e. the deck / the core concept of the post), then you can reinforce the connections between those ideas and strengthen your memory and understanding of the concept. 

(On a tangent, this kinda makes me wonder: "What decks of flashcards would I have if I had taken this approach to learning since my childhood? What if my schools had left me with flashcard decks like this to take with me for the rest of my life? Which bits of information are most essential to hold on to forever?") 

A big shout-out to David for making this feature happen :) 

This is a cool feature, but I'd honestly be surprised if it gets much use.

This is amazing. Incredible execution, it does not go unnoticed!

Thanks :)   Glad you think so!

I'm curious why you decided to make an entirely new platform (Thought Saver) rather than using Andy's Orbit platform.

A few thoughts on this:

• I don't think Orbit existed when we started working on Thought Saver (or if it did, we didn't know about it). When Quantum Country came out I wasn't aware (not sure if anyone was aware?) at the time that it was part of a larger project (maybe it wasn't yet at that point?)

• Thought Saver has a different focus than Orbit (e.g., Thought Saver is not focussed on embedded essays - it just seems that way because the LessWrong team asked if we could add that feature since they wanted to try embedded flashcard quizzes). Thought Saver is more fundamentally focussed on being a tool for accelerating your own learning.

• Also, as far as I'm aware Orbit can't be used in a self-serve fashion right now (?)

• I'll add that Andy is awesome, I deeply respect his work, and I consider him the world expert on the topic of writing essays with memory elements (and on other topics related to spaced repetition as well). I'm excited to see what he does with Orbit!

Thanks, Spencer—I'm excited to see what you learn from this. :)

FWIW, Orbit can indeed be used self-serve, but its OEmbed support (for embedding into user-generated content editors like on here, Medium, GitHub, etc) is not yet available; you must be able to embed HTML blocks. I've not yet advertised this very broadly because I've been looking to cultivate closer relationships with authors in contexts where the medium might be especially useful. Like many commenters here, I fear the existing embedding interaction is probably a net negative in many contexts.

Is this available for automatic crossposting? I guess thought saver will have some way to embed in arbitrary html (iframes? I haven't done this kind of thing much) but will that work when crossposted?

I don't know if I'll use this much, so don't put effort into making it work on my account, just wondering.

Hi, I'm not sure if this works automatically with cross-posting - depends what you mean exactly. You'd have to set it up on each website you want the cards to appear on.

wesome! I thought about such a feature before but didn't expect to suddenly see it added. I'm really curious to see how it will be used. In the meantime, since this post doesn't have flashcards, I get to try making it some flashcards myself :)

uh... Well i tried, but for some reason it created a new deck (with the same name) for each card I created, not really sure why it did that or how to fix it.

Problem was fixed, here are the flashcards:

Hi Yoav! It should be putting them all into the same deck. If you click the search bar it should show all your decks. Can you click feedback in the upper right and tell us what you see there? We've never encountered an issue like the one you're describing. We'd like to help you get to the bottom of it.



When I click the search bar it shows the starting deck I added (How to make the most of thought saver) and 6 decks with the same name (which is the number of cards I created for it)

Hi Yoav! Sorry for the troubles, we'll investigate - I just sent you a private message via LessWrong, could you take a look? Thanks! 


Is there a way to exchange deks between Anki and ThoughtSaver?

Yep, you can import from csv file format and export (your own decks) to csv file format using Thought Saver.

Great. Will look into it.

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