How to remember something forever

[This page is partly a complement to the Memorization 101 page]

[This article is draft that I will need to correct and expand in the future. There’s a lot more that can be said on that topic, but you can find the essential right below.]

The art of memory is powerful, but no matter how good you become, most of your images will fade if you never review them. Whether or not you’re using mnemonics and memory palace, you should know that the most efficient way to get information into your long-term memory is to use what’s called spaced repetition and retrieval practice. This isn’t just my personal opinion, there are at least a few dozens gigatons or peer-reviewed research to back up that statement. Retrieval practice is basically just testing yourself. Don’t just reread your notes, close your book and see how much you can recall without any aid. That’s not just a way to verify what has been remembered, it’s also an extremely powerful way to learn. A related technique is what’s called the “Richard Feynman technique”, named after the famous physician. See this video and this one for the details.

“Active recall is everything. When it comes to learning any type of material, in my opinion, the only activity that really matters is trying to replicate the information, from scratch, without looking at your notes, as if you were lecturing a class. If you can do that, you know it. If you can’t do that, you don’t know it. It’s brutal, it’s intense, it’s also incredibly efficient. It’s the most efficient possible way to learn. (…) Active recall is the only game in town. Any other activity throw it out of your study skills arsenal.” (author Cal Newport during an interview.)

That author I just quoted is mostly right, although I don’t agree with that last sentence. The other fundamental piece of the puzzle is spaced repetition: many reviews at the beginning and less frequent reviews with time. 

I strongly recommend using a spaced repetition software like the free and awesome Anki. You could of course not use any software and just rely on your own instincts to choose when and how you should review, but if you’re anything like me you probably shouldn’t trust your personal self-discipline and judgment. 

  • The complete version Anki
  • The online version that you can access from any computer
  • The mobile versions for Android or Iphone. The Iphone version is $25. It’s the only version of Anki that isn’t free. Fair enough, considering the thousands of hours that the developers invested in this project. The Android version is free. It was developed by a separate team of volunteers. I don’t recommend any of the mobile versions to create new flashcards, but I guess they can be useful for impromptu revisions in random places.

All those versions can be synched to each others.

Don’t be intimidated by the gray interface and the many possible options and ways that you can customize everything. At its core, Anki is just a flashcards program where you write something on one side and see if you can retrieve the answer before checking the answer on the other side. You can use flashcards produced by others, but you should know that it’s usually not a good idea. Making your own cards and choosing what should appear on them is an important part of the learning process. Those cards can be very simple (“Brazil” on one side and the capital “Brasilia” on the other”) or more complex, adding pictures and sounds and all your notes about electromagnetism and so on. Depending on how easily you can retrieve the answer, Anki will calculate how long it should wait before asking you again. No need to reply in writing, just click to indicate how easy or hard it was for you to retrieve the answer.

Here’s a 5 minutes video to explain the basics as well as some optional useful features. And here’s another video explaining how to make particularly memorable flashcards. I personally don’t follow every single one of those recommendations, but it doesn’t mean that those aren’t good advice. 

Anki’s algorithm is made to optimize long-term retention in a minimal amount of time. The result is that for moderately difficult elements of information, you will remember them correctly about 90% of the time. If you want to know everything at any given point, you will have to do some more frequent revisions. To do so you can open a deck and click on “options” or “custom study”. Or you can go to the “tool” section above and select “create filtered deck” and review everything in a particular deck.

Personally, for pieces of information that I want to be able to reproduce anywhere in any circumstance, I like to be able to answer quickly and I prefer to remember 99% of everything correctly instead of 90%. For that reason, for a minority of more important decks, I went to the options and entered a maximum review delay of 2 months. That means that everything I want to remember almost perfectly well will be briefly reviewed at least once every 2 months. If you’re tackling large amounts of information – thousands of words for a new language for example – this isn’t the most time-efficient way to proceed. If you can just accept the fact that you won’t always correctly remember everything, in the long term you’ll be able to learn a whole lot more than if you’re a perfectionist.

Beware of your natural temptation to first review what you already know well and enjoy those little shots of dopamine you get when answering everything easily. It’s of course preferable to first and foremost focus your time and attention and energy on those more problematic and difficult parts.

I know I’m repeating myself, but even if you foolishly decided to avoid using mnemonics and memory palaces, you should still develop the habit of testing yourself and reviewing periodically using spaced repetition. Spaced repetition + retrieval practice = being able to remember amazing amounts of information. Of course, the hardest part is to kick yourself hard enough to get you to actually do the work, but it’s definitely worth it if you care about knowing stuff long-term. Now if on top of that, you can also use mnemonics and build some memory palaces, there are almost no limits to what you will be able to remember. If on most days, after enjoying a good-enough night of sleep, you can sit down in front of Anki or some alternative for some reviews, after a while you’ll be amazed by how much you can manage to remember.

Don’t just tell yourself “yeah sure I’ll review regularly”. You won’t do it. At least most people won’t. Choose exactly when and where you’ll be making your reviews. Make a strict plan and stick to it. Also know that research shows it’s easier to acquire a new habit if you do it immediately before or after something you’re already doing. Every Monday to Friday after breakfast for example.

Developing the habit of reviewing often enough is maybe 80% of the struggle. Reviewing isn’t painful. It doesn’t have to take long when you’re strategic enough with the frequency and the timing of your revisions. It can be somehow fun and rewarding. It’s more fun and more rewarding when you do it often enough so that the recall part isn’t too hard. However, for whatever reason, it’s not an easy habit to develop for most people. 

* To learn more about the most efficient ways you can understand and transform your daily habits, look up some of James Clear’s interviews and/or articles.