The West suffers from a strange aversion to memorization. Dismissing it as “rote”, we live in a world of open books, take home tests, and “just Google it”. Search engines are wonderful things, but the ability to recall what we want to at will, to piece ideas together and play with them fluidly, is incomparable and is necessary to actually understand the things that we care about. The anti-memory path we are on right now deprives us of a great deal of human capital, and on a personal level a much richer human experience.

I myself suffered from this delusion. Why bother memorizing things when I could look up the definition in a search engine or a textbook? There were several contributors to this belief - but the main one was that it was harder to admit that I didn’t truly understand a topic or was slow at it than it was to reject memory as a foundation of understanding 1.

This disease traveled with me until very recently. It had morphed into an obsession with the memex - the mythical, ultimate personal search engine that could tell me everything that I had forgotten. Days were spent poring over filesystem tagging methods and graph databases, dreaming of the perfect tool that would permit me to remember the things that I care about. I had implicitly accepted a lie - that it was impossible for me to remember things myself without a Herculean effort, and that I needed some external device to do this for me. And it was a lie!

You actually can remember all the things you want to remember, forever. It doesn’t require hours of review each day - it only takes ten minutes while you make your coffee. You can cram a specific learning into almost zero review, amortized over your lifetime. Your memorization is only limited by the amount of things that you can learn. It might sound like I am professing a belief in magic, or just lying to you. But I am not.

The solution is called spaced repetition. It turns out that if you periodically review something, the intervals between reviews can keep getting longer and longer before the memory decays. This translates to the following sequence: learn something, write a note for review. Review it a day later. Review it a week later. A month later, six months later, a year later, three years later. This means that you have a roughly fixed amount of review per learning, instead of the unbounded linear review that you might have expected2. Apps exist that make the review scheduling effortless (writing prompts is the more challenging part, which I will address at the end).

The most powerful part of this newfound power is the confidence that I will retain what I learn. This has rejuvenated my enthusiasm for topics such as mathematics and physics that I hadn’t had in a long time - why bother spending an hour reading something interesting on Wikipedia if you can’t remember it? Now I am not afraid to jump into a topic without the guilt that I am wasting time - I can spend 30 minutes on something deep that was inaccessible before and know I will remember it a year from now.

How to start with spaced repetition

  • Read this essay as motivation3.
  • If you have some technical background (or are willing to learn a few things)4 and have even a passing interest in quantum computing - just jump into Quantum Country. This is an online course with the spaced repetition baked in - you just give them your email and they will periodically send you what you learned to review, without you needing to learn or configure another tool. The experience of this course will show you the power of spaced repetition for building up from basic facts to pretty complicated abstract concepts - it is more motivating to experience it yourself first hand rather than just read about it.

Now that you have some understanding of the motivations, it’s time to adopt the practices for yourself. First read this essay about how to write good review prompts, and try to make prompts about it as you read through it. You can play with the note system for a while before moving on to the sequel to that essay, this recursive piece that uses spaced repetition to help you remember best practices for spaced repetition.

Good luck with your spaced repetition journey, and if you enjoy it please help us evangelize it. Raising the world’s bar for human cognition and fulfillment is such a fundamentally important goal that I cannot overstate it, and I sincerely hope that you join us on this mission.

  1. Secondary reasons include too much focus on credentials leading to too large of a course load, university assessment methods relying on homework and take home tests, and a lack of followup after classes ended. ↩

  2. Of course, sometimes you do stumble with something - you can just reset the review intervals, starting with a day again until you’ve worked back up to a year. This happens infrequently. ↩

  3. Thank you whoever in the South Park Commons learning forum introduced me to Andy’s (and by extension Michael Nielsen’s) work. ↩

  4. Basic linear algebra, complex numbers, and logic gates ↩