Some people have asked how I can learn so much from what I read. I don’t believe I do – in fact, I believe I squander most of what learning potential does exist. I’m trying to change that, and this is how. Starting back up with spaced repetition has afforded me to also read non-fiction books differently.

Before spaced repetition1¹ I.e. in practise since I started reading more heavily again, which was around the summer of 2019 I think. Thanks, Joel, for inspiring me to start reading again!, I used to:

1. Read one book at a time in one pass, making notes as I went.
2. Make use of my new knowledge immediately as I gained it.
3. A few weeks after finishing the book, review the notes.
4. A few more weeks after that, forget everything I learned from that book.

This mostly worked, but the last part is really annoying.

I have read a lot of stuff, and a lot of it has been useful knowledge. On this web page2² At the time I write this article. I have published about 300,000 words. My private reading notes currently sit at around 1.5 million words.3³ Which I happen to know is 50 % more than all seven Harry Potter books together!. If somewhat technical English prose has, to a first approximation, 6 bits of entropy per word4⁴ The Word Entropy of Natural Languages; Bentz & Alikaniotis; 2016. Available online., that means I have made notes worth just over 1 MB of raw information.5⁵ Which means it’s half a kilobyte per day on average. Crazy!

It’s a little sad that I have learned 1 MB of stuff and forgotten it again. Sure, I can usually find what I need to re-learn in my notes, and if not, at least the notes point me to roughly which part of the book I need to re-read. But looking things up in the notes or re-reading the relevant parts of a book is slow and breaks flow. It’s also a little embarrassing that I hypothetically know all these neat techniques6⁶ Like how to compute effect size (odds ratio) from a contingency table. but if someone asks me to do it on the spot, I still have to look it up.

Especially annoying is forgetting basic notation and foundational arguments presented early in the book. Usually, they are needed to understand the later parts of the book, but I have forgotten them by the time I get to them so again, I have to go back to the notes.

My method of reading is the best I’ve had so far, but I sense there’s room for improvement. I have started trying a different method of reading, inspired by Wozniak’s idea of incremental reading7⁷ Incremental Learning; Wozniak; 2013. Available online., but not going quite as far. Here are some changes I’ve made:

• I read slower. I intentionally linger on fundamental concepts, notation, embedded exercises and thought experiments. I encode them into flashcards, and after I’ve read a few sections/chapters, I do a one or two iterations of spaced repetition before I move on to the next few sections/chapters.

  This means I can only read a few sections/chapters per week, but it also seems like it allows foundational concepts to be more firmly rooted in my brain, which helps with comprehension of later ideas.

• I read multiple texts on the same subject concurrently, and mix in a few other subjects as well to allow some time to pass and the initial concepts to sink in. (Since I can only read a few sections/chapters per week and book, I might as well read multiple books at the same time to fill out the additional reading time.)

  My previous experience with this is that the texts interfere with each other, but with spaced repetition I can instead make them reinforce each other, by studying their differences and similarities.

• I’m no longer as insistent about finishing a book before I pick up the next one, because I’m more confident I will remember the early parts of the book when I pick it up again to continue, even if a few months have passed.

• Similar to the previous point, I no longer feel like it is a waste of time to read up just a little bit on a subject, because, again, I know it improves my knowledge even if only in a small dose.

  Previously it was important to me to dive deeply because it also served as memory practise to reinforce the shallow parts. Now I have a system that automatically reinforces those for me, even if I don’t dive deeper.

• I spend more time thinking about where my future self might be confused, and focus study on those things, rather than what sounds cool in the moment but might not be that useful or difficult later.

I’m sure I’ll discover more changes as I go.

Referencing This Article

• Intuition and Spaced Repetition