What a mnemonic is
A mnemonic is a memory aid: a deliberately constructed hook that makes information easier to hold and retrieve. Most mnemonics work by turning something abstract or arbitrary, such as a list of unrelated terms, into something that has structure, sound, humor or a picture attached. The brain tends to hold on to meaningful and vivid material more readily than bare facts.
Mnemonics are useful for a specific job: remembering items you cannot work out by reasoning, such as a fixed order, a set of names or a vocabulary word. They are not a substitute for understanding a topic.
Acronyms
An acronym takes the first letter of each item in a list and forms a word. A familiar kind is a word made from the first letters of a sequence, which you recall as a unit and then unpack. The classic example in schools is a word for the colors of the rainbow, or the names of the Great Lakes arranged to spell a word.
Best for: short ordered or unordered lists where you only need the first letter to jog your memory.
Limitations: you still need to know what each letter stands for, and a word that spells nothing sensible is hard to use. Acronyms also stop being useful when the items themselves are unfamiliar, since a letter will not rescue a concept you never learned.
Acrostics, or phrase mnemonics
An acrostic uses the first letters of the items to build a sentence instead of a word. The sentence is easy to remember because it is meaningful, and funny or odd sentences are often the most memorable. For instance, a sentence beginning with the same letters as the planets in order, or the notes on the lines of a music staff.
Best for: longer ordered lists where a pronounceable acronym is not possible.
Limitations: you must remember the sentence and then convert it back, which adds a step. Make sure the sentence is easy to recite, and create your own when possible, since your own phrases tend to stick better than borrowed ones.
Rhymes and songs
Rhythm and rhyme give information a fixed shape, making it harder to misremember. Many people learn spelling rules, the number of days in each month, or multiplication facts through verses and tunes.
Best for: rules, sequences and facts that you want to be able to say fluently, and for younger learners.
Limitations: the rhyme preserves the words, not necessarily the meaning, and a rule recalled in rhyme can still be applied wrongly. Rhymes also exist for some rules with many exceptions, so check that the rhyme is accurate.
Imagery and vivid association
Pictures are often easier to remember than words. A basic imagery mnemonic links a new word or fact with a mental image, ideally something odd, active and detailed. If you are learning that a certain foreign word means “bread”, you might picture a loaf wearing a distinctive hat that sounds like the word.
This is sometimes called the keyword method, and it is often used for vocabulary building in a new language. It takes a bit of creativity, but the effort of inventing the image is itself a form of processing the word.
Best for: isolated pairs, such as word and meaning, name and face, or term and definition.
Limitations: it is slower to build than other types, and the sound-alike link can mislead you if the picture does not carry the real meaning. It works better for concrete things than for abstract ideas.
Chunking
Chunking groups items into smaller meaningful units. A long phone number is easier to hold as a few groups than as one string of digits. This reflects the limits of working memory: you can hold a handful of chunks, and each chunk can contain several items.
Best for: numbers, codes, formulas and long terms.
Limitations: the chunks must be meaningful to you, or they are just short, separate strings.
The method of loci and the story method
Two other techniques deserve a mention. The memory palace places items along a familiar route, and is covered in its own article. The story method links items in a chain of events, such as a short narrative in which each element appears in order. It is good for ordered lists, but a broken link can lose the rest of the chain.
Choosing the right mnemonic
| Material | Often a good fit |
|---|---|
| Short list, order not vital | Acronym |
| Longer ordered list | Acrostic or story |
| Rules and patterns | Rhyme or song |
| Word and meaning pairs | Imagery or keyword method |
| Long strings of digits | Chunking |
| Ordered list of many items | Memory palace |
Making them work
- Make your own when you can. The work of inventing it helps you learn.
- Be specific and vivid. Strange, funny or emotional associations are usually easier to recall than dull ones.
- Test yourself afterward. A mnemonic that you have not practiced retrieving may fail when needed. Combine them with active recall and review them over several days.
- Check accuracy. A mnemonic that encodes a wrong fact is worse than none.
- Learn the meaning too. Remembering the names of the planets in order is different from understanding the solar system.
Where mnemonics fall short
Mnemonics help you retrieve what you have already organized, but they do not build understanding. A student who has memorized the steps of a method through a rhyme may still not know why those steps work, and will struggle when a question changes slightly. For this reason, mnemonics are best used for the fixed pieces of a subject, while explanation, practice and discussion handle the rest.
Many learners find that a small number of well-chosen mnemonics is more useful than a large collection that is hard to keep straight. Start with the facts that are causing you the most trouble, try one technique, and notice whether it holds up a week later.