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I Memorize Things

Background

My family placed unusual demands on memory. We moved 16 times before I started my senior year of high school, so I had to learn 17 addresses, phone numbers, groups of kids' names, and ways home. A routine part of outings was having my dad pull over and ask me how we had got there. I wasn't allowed to say 'left', or 'right', but had to describe every turn using compass bearings.1

My uncle was a California highway patrolman and later a marshal. Annoyed that even sober people couldn't do it, he made me memorize the alphabet backwards. He himself used to casually memorize the license plate of every car he parked near (and as a kid I was terrified on behalf of the hypothetical bad drivers who might ding his truck and drive off thinking he couldn't find them).

We used to visit the jail regularly when I was a kid back in California for the summers. As a result I conceived the (I now recognize) bizarre idea that everyone eventually goes to prison. After that, I began to notice stories of political prisoners sustaining themselves in isolation with foreign languages and poems they had memorized, and this awoke an urgent desire to stock my brain for my time in solitary. (The Count of Monte Cristo especially affected me.)

She denies this now, but my mother thought I should just be able to memorize the times tables overnight when our math teacher told us to get help learning them at home. She paid me $22 in today's dollars to leave her alone and go do it on my own.

Finally, when I was 11 I found a book on memory techniques written by a magician. I learned all the techniques and started using them at school.

Applications

With that background, here are a few examples of things it seemed normal to do.

For every essay exam in college I would guess a handful of questions I thought might appear, find commonalities between pairs of questions so I could reduce them to themes, then write 3-5 essays (with citations) on those themes, then memorize the essays. I never had to answer an essay question I hadn't already written an essay for. When I told my mom the strategy I had come up with to guarantee A's, she said she had done exactly the same thing (she earned her BA and PhD in three years each while raising two kids).

Because I misunderstood a line on our syllabus, I memorized the title, recording date, and band composition for over 150 classic jazz recordings. When my roommate took music theory from the same professor a year later, the professor said he couldn't listen to any complaints about how hard it is to remember chord resolutions and gave them my example as explanation.

As a grad school TA I would memorize students's names as they introduced themselves on the first day, then repeat them back immediately and again at the end of class.

I memorized the entire argument of Plato's Republic using a memory palace and memorized Odysseus and Achilles's exchange in the underworld in ancient Greek.

When I learned in my first German class that prepositions take different cases, I extracted every preposition from the text and memorized their cases over a weekend. (A friend later taught me a couple of songs that he learned at the Goethe Institut that accomplished the same thing with way less effort.) With the help of a wonderfully patient professor, I memorized dozens of poems by Goethe, Rilke, and Heine so I had an internalized pronunciation reference.

You are a Robot, You Lack Creativity

Growing up, memorizing things seemed practical and ordinary. In the same way that you might pack a lunch when you know you're going to need a lunch, why not just pack a few things into your head whenever you think you might need them later?

Since university, though, I've regularly run into people who are philosophically opposed to memorization. These are usually engineers or scientists that I respect, so it often made me feel bad.

I observed that people who are very experienced with concepts eventually memorize them through repeated use, then work with them at a higher level of abstraction. I thought you should jump-start this fluency by memorizing up front. The contrary position was often that any memorization is 'rote memorization', which is by its nature evil, anti-creative, and evidence of a lack of true understanding. Instead of memorizing, the counterargument continued, people should derive concepts from first principles as they need them. Steve Yegge says "Having a good memory is a serious impediment to understanding. It lets you cheat your way through life."

These criticisms used to sting, but in recent years, conversations of this sort have been followed by the critics forwarding a link to Michael Nielsen's article on memorization with Anki. I am grateful that Michael wrote this, as it rebuts a lot of the arguments against memorization and makes a persuasive case for.

Techniques

Like Michael, I use Anki and SRS (and flashcards generally) to memorize things, but I also use many of the techniques that he eschews. Below I describe the non-SRS techniques I find useful, give a brief description of how they work and what they are good for, and link to an explanation or example.

TechniqueHow to use itEffort
Mnemonic LinkAssign nouns to the items you want to memorize, then link them together with action verbs. Good for memorizing long lists of concepts, especially where order matters. Short example of how to memorize the Chinese Zodiac in a few minutes.You can learn it in an hour and use it immediately.
Major SystemUse consonants to represent strings of digits, "hydrate" them with vowels to create words, then connect the words together using Mnemonic Link. Great for memorizing dates or arbitrarily long numbers.An hour to learn, but requires practice over a week or two to internalize.
Peg SystemUse a fixed set of words from the Major System as ordinal number hooks for arbitrary lists.It's an extension of the Major System, so minimal effort if you already know that.
Memory PalaceRemember items by mentally placing them in order in a well-known space.Another one that is easy to learn but takes some practice to internalize.
Anki/Spaced Repetition/Flashcards [see references]Review regularly, especially just as you're about to forget. Useful for memorizing just about anything over time.Low effort, potentially low time investment, but elapsed time can be high.

Many people at school and work have asked me to show them how to memorize things, but most are put off by the initial intricacies of the Major System (it's certainly easier to just continue writing things down).

I made a pdf cheatsheet for people who want to learn to memorize numbers and dates easily — print it out, fold it up, and carry it around while you practice. Using it will naturally encourage you to practice mnemonic link, and if you want to add a memory palace later, it will seem easy by comparison.

major system cheatsheet

Meta-Techniques

I use all of these techniques (including Anki and spaced repetition), but I find Mnemonic Link and the Major System the most routinely useful. Why use multiple systems? Why not just use flashcards and spaced repetition for everything I want to learn?

I use memorization techniques in three ways: to pin down a distraction, to build a foundation or provide context for an extended learning effort, and to reinforce curiosity so I can build momentum to learn something. For two of these approaches, how quickly I make something permanent is relevant, so these meta-techniques are better for me than flashcards. With the final meta-technique, the experience of learning is different — I'm trying to change my attitude toward something, or tie a new interest to existing interests; in these cases, again, different techniques are helpful.

Staple Gun

I'm afraid the first example of how I use these techniques vindicates the critics — I really do use them for memorizing arbitrary trivia! But if you are the kind of person who will write a script to automate a recurring task, the Staple Gun approach to memorization is the equivalent. Of course you can look up a fact or the steps of a process whenever you need to, but with training, you can pin things in memory in less time than it takes to look them up twice.

In college, my edition of Meditations on First Philosophy had a portrait of the author on the cover that made him look like a musketeer. Every time I saw it, it made me curious, but it was never important enough to pursue (and hard to google: "Why does Descartes dress like a musketeer?"). Finally, I looked up and memorized a few dates:

It turns out that Descartes had military ambitions and that lots of people dressed like musketeers when he was alive. In some sense, I may not really want to know this for its own sake! And I certainly get bored of seeing such trivial facts in my flashcards. Partly because it is trivial, when something piques my curiosity repeatedly, it's often worth a minute or two of effort to staple it in place permanently.

This is exactly the kind of rote memorization that people object to, but once you know the Major System, it takes less time to memorize something than to look it up again later. Of course that's not a good reason to memorize things! But there are two benefits: it reduces the threshold of what's worth learning, and the more dates you have welded into your brain (especially about things you are actually curious about), the easier it is to place new things in historical context, allowing your understanding to accumulate. If I read that Newton's insights into calculus occurred during the plague years, I can put that in the context of Descartes's life and consider how long it took for his analytic geometry to spread and influence other thinkers.

Most useful techniques: Major System, Mnemonic Link

Deep Foundation

One of the 16 moves our family made was to Florida, where we lived first on the Kissimmee River in the swampy interior, then later on a sailboat on Anna Maria Island. Every morning I would jump overboard and swim around the deep-sunk barnacle-covered pilings that supported the dock connecting us to the island.

A new domain can sometimes seem like a big, undifferentiated expanse of water (or swamp!). Memorizing does two things: it lets me drop pilings down into a firm foundation so I have something to build on; it also creates landmarks that help me orient myself as I learn.

As Michael notes, you usually want to work with the important abstractions. But how do you get there? You can use flashcards and build up your understanding over time, but it can be faster to choose a few things (sometimes even arbitrarily) and memorize them immediately through enhanced attention rather than over time through repeated exposure.

Those "mental pilings" will provide a foundation on which to start affixing new information to build a more elaborate structure. For example, when I read The Republic for the nth time in grad school, I first memorized the order in which the characters appeared. This gave me a framework to hang their arguments from so I could recall them in discussion, and it made all of the participants seem familiar. When my colleagues and I read Jurafsky and Martin's Natural Language Processing text, I memorized the attributes of the common activation functions — knowing what they have in common is a first step toward abstraction, and holding them all in my head lets me manipulate them mentally to identify those commonalities.

The 'landmark' use case of memory pilings is also important — whenever I read something that mentions activation functions, I now have multiple concrete examples as references. Having this background (even though it is acquired in almost random fashion) both lets me focus on new ideas, and reassures me that I am in familiar territory, giving me confidence to keep pushing forward.

This Deep Foundation approach differs from the Staple Gun approach in that you are learning or creating context, not just nailing down arbitrary facts. A common metaphor for learning is building an "edifice of knowledge" — memorizing can let you build the foundation quickly and move on to something you can inhabit or use; it can also help you feel at home right away.

Most useful technique: Memory Palace

Nerve Splicing

In the Phaedrus, Socrates tells the story of Thoth, the Ibis-headed god who 'invented numbers and arithmetic and geometry and astronomy, also draughts and dice, and, most important of all, letters'. He shared his invention of writing with the King of Egypt, praising it as 'an elixir of memory and wisdom'. The king argued that on the contrary, writing 'will produce forgetfulness in the minds of those who learn to use it, because they will not practice their memory'. Socrates makes a further objection that texts are 'like paintings' in that they can't engage with the reader.

One irony is that we only remember this text because it was written down, and another is that the argument is now reversed and we prefer writing.

The last major meta-technique I use is an idiosyncratic approach that tries to answer Socrates's objection and make that which can't speak (i.e., those metaphorical paintings) come alive.

Many texts that explain a concept, especially in math or philosophy, are intentionally terse. The goal is to communicate clearly and concisely, and any details about how the lemma was arrived at or its consequences are often 'left as an exercise for the reader'.

These dense nuggets are hard to get a grip on, and therefore hard to assimilate and incorporate into your repertoire. You need to be able to manipulate a concept in order to use it (Timothy Gowers cites Terence Tao talking about 'putting a handle on the wrecking ball'). In addition, it needs to engage your attention both so that you come back to it, and so that it starts to suggest itself as a way to solve problems.

In these cases I make an inventory of every connection I have to the concept, even remote or fanciful ones, then try to distill them into a metaphor that represents the function. If the metaphor is accurate, it ends up being a model of a model, a kind of scaffolding that can come down later once I have fully assimilated the new concept. And since the model is based on and extends my existing interests, I have a natural impulse to continue to learn about the topic and let the graft grow.

I think of this as 'Nerve Splicing', because you are grafting a new concept onto existing ones and making the new idea vibrate with interests you already have. This is especially effective if the topic is somewhat dry. If you can connect it to things you already know, or especially to existing interests, you can animate a topic for yourself, then let your natural curiosity deepen your relationship to it.

This meta-technique is by its nature idiosyncratic — an example is this exploration of XOR Swap.

Most useful techniques: Drawing (see Miscellaneous techniques below), Mind map

Miscellaneous

Many of the techniques above trick your visual or spatial apparatus into remembering things for you. Here are some non-mnemonic practices to help you "think in more memorable ways":

Why Memorize

As noted above, the most practical reason to memorize is chunking. Memorizing things lets you reach a higher level of abstraction faster.

Another benefit is efficiency. Memorization techniques don't necessarily make it easier to learn things. Learning something permanently right now often takes the same amount of mental effort as reviewing it multiple times over a couple of weeks, but the effort is compressed into a shorter elapsed time, so your efforts are more effective.

There is also a residual effect, just as with exercise. If you work out, your metabolism increases somewhat even when you're resting. It's the same with memory — if you practice paying enough attention, you start noticing and remembering things even without special effort.

This leads to another advantage: with practice, you develop a clear sense of what it feels like to concentrate hard enough to memorize something. This gives you an internal gauge of whether you are paying enough attention independently of whether you are using memory techniques.

Two more uncommon benefits:

At parties or conferences where attendees are meeting lots of new people, I often hear them capitulate, saying something like, "I'll never remember all these names." Once you gain confidence that you can remember an arbitrary number of names, it's self-reinforcing. It can even become something like a game — I used to be too shy to talk to more than a handful of strangers at a gathering; now, having the goal of "collecting" all the names makes me forget any self-consciousness.2

Finally, I think the biggest benefit is the one I learned in prison:3 Memorizing lets you assimilate things you admire and make them a permanent part of you; if you put things you care about into the "unrobbable bank" of memory, they will suggest themselves to you in meaningful situations for the rest of your life.

Resources and Inspiration


  1. This really helped me once. My first day on the job as a blacksmith's apprentice in Würzburg, Germany, the foreman asked if I could drive one of the pickups back to the warehouse. At the first intersection, he forgot I was following him and sped through a red light. I was a foreigner with no cell phone, no driver's license, no work permit, a truck I couldn't account for, and a limited vocabulary, but before I could worry about it too much, I realized I actually knew the way back. Thanks, Dad.[return]
  2. On a group trip to Ecuador a couple of years ago, 30+ people introduced themselves the first night. After, the organizer offered a beer to anyone who could repeat all the names. I said I could do it. He then asked everyone to rearrange themselves to make it more difficult. I won the beer, which gave everyone a default conversation topic ("How did you do that?").[return]
  3. As a guest, remember.[return]

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