An Introduction to Mnemonics

11 minute read

Thus far in this series, we’ve talked about how memory can be boosted with external tools, namely spaced-repetition systems like Anki. It would be a massive oversight to conclude any extended discussion of memory without touching on another, older and more fundamental, technology for boosting memory, one that requires nothing more than your brain – the wide world of mnemonic techniques.

Mnemonics is the art of reversibly substituting easy-to-remember things for difficult-to-remember ones. As I discussed in my two Human Memory By Example posts, people are much better at remembering some things than others. For instance, we can often vividly and accurately remember places we’ve been, even years later after being there only once, while long strings of meaningless numbers are nearly impossible to learn even with concerted and extended effort. What if we could memorize places instead of numbers, while still retaining the ability to produce the numbers at the end? That’s the promise of mnemonics.

If you’ve never spent much time with mnemonic techniques, this may sound like pie in the sky, but mnemonic techniques may in fact be some of the easiest cognitive skills you’ve learned. I consider it absurd that they’re not a part of any standard school curriculum I’m aware of, given their obvious application to everything else that happens in a school and the low barrier to entry. If you have normal cognitive abilities, know the tricks, and have some hours to kill, you can absolutely learn seemingly-impressive party tricks like memorizing the order of a shuffled deck of cards. (Such tricks tend to have limited application in real life, but can help you practice a variety of mnemonic and related skills and are surprisingly fun.)

This said, mnemonics are not a panacea. While they can produce stronger and longer-lasting memories, no mnemonic technique can reliably and permanently prevent forgetting unless you review regularly. Learning material with mnemonics also tends to take longer and may produce memories that don’t integrate as well with other material, since you are memorizing substitute information. Because mnemonics are powerful, using mnemonics also makes it easier to miss the fact that you’re learning information of limited value, information you don’t fully understand, or information presented in a needlessly difficult way.

For these reasons, I tend to consider the use of mnemonics a last resort as part of a global spaced-repetition-based learning strategy; most things can be adequately remembered “naturally” if you follow standard best practices for learning with an SRS. “Last resort” does not necessarily mean that you only resort to mnemonics once you’ve been struggling to learn something for weeks, though. Once you gain some familiarity with both mnemonic techniques and the kinds of things you often need to learn, you’ll develop an understanding of what things will be tricky to learn without mnemonics, and you can apply them from the start on these items.

Note: Some people dispute that mnemonics don’t allow you to remember things more or less permanently, or that they’re difficult to quickly use on some types of information, or that they make integration with other material more difficult, but I’ve noticed that most of these people seem to be selling books about mnemonics. I’m willing to believe that only people who have found mnemonics unusually helpful write books about it, but I have yet to meet anyone in real life who uses mnemonic techniques to the extent some of these authors claim to, so I’m pretty suspicious of the claims.

Things that deserve mnemonics

So what are the most effective ways to use mnemonics? Here a few things you’ve probably wanted to learn at one point or another that are intrinsically difficult to memorize and amenable to simplification by mnemonic techniques:

  • Long lists of items or instructions. Over the long term, remembering groups of more than two or three items without some kind of cognitive aid strains most people’s abilities. When we are seemingly able to do this, we typically are relying on some kind of mnemonic device without realizing it.
  • Numbers and codes of all types.
  • Root words in a foreign language that don’t show obvious resemblances to words in other languages you know. These are essentially meaningless bits of sound when the language is new to you, so they tend to be quite difficult to remember.
  • Confusingly similar pairs or sets of items – these could be anything from foreign words to technical terms to keys to highway exits. Because the items are similar by definition, it’s much easier to keep them straight after adding some extra attributes to make them look more different.

Things that probably don’t deserve mnemonics

The flip side:

  • To-do lists, calendars, and other organizational systems – in the general case. While you certainly can keep these things in your head if you want, and many people have explained how to do it, in 2020 when everyone can easily write them down or put them in their phone, it feels more like a time-consuming party trick than a useful choice. Further, some things are easier to think about on paper than in your head; your calendar or to-do list is as much a way to get an overview of things you need to do as a way of blindly storing and retrieving information. I’m sure someone has a good reason to want to memorize their calendar, but if you’re not already convinced it’s practical, I doubt it will be so for you.

    On the other hand, it’s useful in some specific cases to be able to temporarily remember a task or idea when you have no access to an appropriate tool to record it. I hope to do a whole post on techniques for this at some point.

  • When using an SRS, understandable terms in your native language, comprehension questions, or other flashcards you have no reason to believe will be difficult. Adding mnemonics is a waste of time and a distraction for most of these, when you’ll likely easily remember most of them without. And if you find yourself struggling, that’s as likely to mean that your cards are bad as that they deserve mnemonics – more on this later.

  • Material you don’t have a compelling need to know. As with Anki, it’s easy to go crazy when you learn some mnemonics and realize you can memorize things that were previously out of reach to you. But unless you expect some actual value to come out of it, spend your learning time studying useful things!

Types of mnemonics

Most mnemonic techniques involve the production of creative and memorable mental images. Exactly what form these take depends on the individual practicing the technique, but the more vivid, the more senses involved, the more unusual, and the more action or narrative thread involved, the more effective the mnemonic will be. Some techniques instead, or in addition, involve the production of meaningful words or phrases; words or phrases that can also be visualized are especially effective.

The rules about making mnemonic images more effective work somewhat like the old saw in which someone says not to think of a purple elephant: anyone listening will, of course, immediately imagine a purple elephant, and they’re also unlikely to forget the idea of not thinking about a purple elephant. A purple elephant is strange, funny, and easily understood and visualized despite not existing in real life. The image could be made even more effective if we imagined ourselves, for instance, running over and jumping on the purple elephant. The remaining problem, then, is converting ideas you want to remember into these evocative surrogate images in a way that you can reverse later to reconstruct the idea.

You can make up your own techniques for doing this, but because people have been doing this for thousands of years, you might as well start by learning a few established techniques to get a good idea of what works and what doesn’t. Here are several:

  • Often a new term or concept “sounds like” some other term; if you can make it sound like something silly and visualizable, you’re set.

  • The Major System is a popular and easy-to-learn method for memorizing numbers. Each digit is mapped to a series of related consonant sounds (for instance, the number 2 makes an n sound), and the resulting consonants can be freely interleaved with vowels to create words and phrases. In the second Human Memory By Example article, I gave the example of converting the number 14150405 to the phrase “Turtles are slow.”

  • The letters of the alphabet can be assigned concrete objects starting with those letters; for instance, the letter Q might become a queen. You can then memorize strings of letters that otherwise have no meaning (for instance, random codes or license plate numbers) as objects that can be connected into a story.

  • It’s common to need to place things in categories: what day of the week something happens on, what grammatical gender or conjugation a word in a foreign language has, and so on. You can place items of each category in arbitrary imagined locations or, especially if you have additional information to associate them with, assign each category a color and make your imagined image take on that color. For instance, things that happen on Mondays might be gray, or located in your garage, while things that happen on Wednesdays might be red, or located at the zoo.

A special problem in mnemonics is the memory of lists. Not only are lists a common and difficult-to-remember type of item in themselves, it’s often important to take other items you’ve memorized and put them in a list so you can find them later. As such, these are in some sense meta-techniques: you may apply some of the techniques listed above to memorize individual items, then link them together into lists.

  • Method of loci: This technique dates back at least to ancient Greece and was regularly taught for thousands of years, but many people today have never heard of it. To use this method, you imagine yourself walking through a place you know well, real or fictional, and mentally superimpose objects representing the ideas you want to memorize on the landscape, in specific locations (or loci). Later, you can “walk” back through the space to revisit the ideas.

    This may also be called the “memory palace” technique or simply “the art of memory.”

  • Linking: This technique is the method of loci without the imagined place. Instead of using a background location, image 1 is simply imagined interacting with image 2, then image 2 interacting with image 3, and so on. With the overlap in place, you can walk your way down the list by finding the “other” pair associated with each image. This method can be faster and easier than the method of loci, but is also riskier because forgetting one link may mean you lose track of other items as well.

  • Peg systems: This technique is helpful when you need to associate numbers with each item. You first memorize a list of items called pegs, which are arbitrary images associated with the numbers (the Major System is a popular way to make the associations of these images to their numbers memorable). Then you can memorize the number of any item by linking your mnemonic image for the item with the peg. For a system in which you can either “scan” or get the number of an item, you can combine this with the method of loci.

  • Initialisms: For items that have a strong linguistic component, you can make up silly phrases where the first letter of each word matches the first letter of each list. These have the benefit of being more easily recorded on flashcards or shared with other people, though they may not be as effective and they’re a poor choice for long lists.

The hardest part of many of these techniques is memorizing the mnemonic mappings themselves. While you can try to pick associations that have some meaning to you, often with some success, there is likely no particular reason Wednesdays should be red, or the number 2 should make an n sound. Memorizing mnemonic mappings well enough to use them effectively can admittedly be infuriating at times. If you stick with it, though, you’ll soon enough be rewarded with a personalized system that will work for the rest of your life.

In future posts in this section, we’ll look a bit deeper into several of these techniques and how you might use them with Anki. This series is not intended to be a definitive guide to mnemonics, however; while I can use mnemonics perfectly well, I’m hardly an expert and many good resources have been written already. If something in this list intrigues you, you can and should go learn about it right now!