What is a mnemonic device?

A mnemonic device is any memory aid that links information that is hard to remember to something easier to remember: a word, a sentence, a rhyme, an image or a place. Common examples are acronyms such as HOMES for the Great Lakes, sentences such as “Please Excuse My Dear Aunt Sally” for the order of maths operations, and rhymes such as “In fourteen hundred and ninety-two, Columbus sailed the ocean blue”.

What are the main types of mnemonic devices?

The main types are acronyms (a word made from first letters), acrostics (a sentence whose words start with those letters), rhymes and songs, chunking (grouping items into fewer units), the keyword method (a sound-alike word plus an image, used for vocabulary), the story or link method (joining items in a story), and the method of loci or memory palace (placing items along an imagined route).

Do mnemonic devices actually work?

Yes, for the specific material they are built for. In a classic 1975 study, people learning Russian vocabulary with the keyword method scored 72% on the key test against 46% for a control group. The limits are just as well documented: a 2013 review of study techniques rated the keyword mnemonic as low utility for students because it is hard to apply to many kinds of material and its benefits were shown mainly over short intervals.

What is the difference between an acronym and an acrostic?

An acronym is a single word made from the first letters of the items, such as HOMES (Huron, Ontario, Michigan, Erie, Superior). An acrostic is a sentence in which each word starts with the first letter of an item, such as “Every Good Boy Does Fine” for the notes on the lines of the treble clef (E, G, B, D, F). Acrostics are useful when the first letters do not spell anything.

How do you make a good mnemonic?

Make it short, concrete and personal. Turn abstract items into things you can picture, keep the items in the right order if order matters, link the cue tightly to what it stands for, and then test yourself on the original material, not only on the mnemonic. A mnemonic you invent and practise is usually easier to recall than one you only read once.

Do mnemonic devices make you smarter or raise IQ?

No. They improve memory for the material you encode with them, which is valuable, but there is no good evidence that they raise general intelligence. A 2003 study of people with outstanding memory found that their advantage was not explained by exceptional intellectual ability; what set them apart was their use of a learned strategy.

Mnemonic Devices: Types & Examples

A mnemonic device is a memory aid that ties hard-to-remember information to something easier to remember, such as a word, a sentence, a rhyme, an image or a place. HOMES for the five Great Lakes, “Please Excuse My Dear Aunt Sally” for the order of operations and “thirty days hath September” are all mnemonics. They work because they give arbitrary material a structure your memory already handles well, and the research shows both how much they help and where they stop helping.

Mnemonic devices at a glance

What they do: add a retrieval cue. The mnemonic is not the information; it is a route back to it.
Best for: lists, sequences, names, vocabulary, formulas and facts that have no meaning of their own.
Weak for: understanding. A mnemonic can help you recall the steps of a method without helping you apply it.
Strongest evidence: the keyword method for foreign vocabulary and the method of loci for ordered lists.
Not a shortcut to IQ: they improve memory for what you encode, not general reasoning.

The main types of mnemonic devices, with examples

1. Acronyms

A single word built from the first letters of the items. HOMES gives Huron, Ontario, Michigan, Erie and Superior; ROY G. BIV gives the colours of the rainbow in order (red, orange, yellow, green, blue, indigo, violet). Acronyms are fast to learn but only work when the letters can be made into something pronounceable, and the cue is only a first letter: you still have to know the words.

2. Acrostics (first-letter sentences)

A sentence in which each word begins with the first letter of an item. “Please Excuse My Dear Aunt Sally” (PEMDAS) gives parentheses, exponents, multiplication, division, addition and subtraction; “Every Good Boy Does Fine” gives the notes on the lines of the treble clef (E, G, B, D, F). An acrostic keeps the order and works when the letters do not spell a word. Like an acronym, it helps you retrieve items you already know rather than teaching you new ones.

3. Rhymes, rhythm and songs

“Thirty days hath September”, “i before e except after c” and the alphabet song all use sound to hold words in place: a missing word breaks the rhythm, which tells you something is wrong. In two experiments with 100 participants each, Patricia Purnell-Webb and Craig Speelman (2008) found that rhythm, with or without a melody, helped people recall the words of a text, and that a familiar rhythm or melody helped further. Their interpretation is that rhythm provides a frame for the words to attach to.

4. Chunking

Grouping many items into a few meaningful units, the way a phone number is split into blocks. Strictly it is a way of recoding rather than a separate trick, and it is the reason a 10-digit number is manageable at all. Our article on chunking covers the research, including the student who stretched his digit span from 7 to 79 digits after more than 230 hours of practice.

5. The keyword method

Designed for vocabulary. You pick an everyday word that sounds like part of the new word (the keyword), then picture the keyword interacting with the meaning. Richard Atkinson and Michael Raugh (1975) taught Russian vocabulary this way: on the most critical test the keyword group scored 72% correct against 46% for a control group who learned however they liked. It remains one of the best-replicated mnemonic effects.

6. The story or link method

You join the items into a short, vivid story, each one triggering the next. A shopping list of milk, keys and stamps becomes a carton of milk unlocking a door with a stamp stuck to it. The story supplies the order and the images supply the cues.

7. The method of loci (memory palace)

The oldest and best-studied technique: you place an image of each item at a point along a route through a place you can picture, then walk the route to recall them. It is the method competitive memorisers use. In a 2017 study, people with no memory training who practised it for six weeks improved, and the gains were still measurable four months later. Our full guide to the memory palace explains how to build one.

Why mnemonic devices work

Most of what we struggle to remember has no structure of its own: a list of lakes, the order of operations, a word in a language you do not speak. Mnemonics borrow structure from things memory handles well:

Images: concrete, odd, interacting images are easier to recall than abstract words.
Places and order: a route or a sentence carries a fixed sequence, which protects the middle of a list (where forgetting is usually worst, as the serial position effect shows).
Sound: rhyme and rhythm constrain which words can fit.
Fewer units: chunking reduces the load on working memory, which can hold only a handful of items at once.

In every case the mnemonic adds a cue at the moment of learning that you can use again at the moment of recall. That is why it helps to create the mnemonic yourself, and why the same cue can stop working if it gets tangled with other associations.

What the research says about the limits

Benefits can fade. Alvin Wang, Margaret Thomas and Judith Ouellette (1992) ran four experiments with second-language vocabulary and compared immediate and delayed tests between groups. Long-term forgetting was consistently greater for learners using the keyword method than for learners using rote rehearsal, so the early advantage did not simply carry over.
They suit some material, not most. In a large 2013 review of ten study techniques, John Dunlosky and colleagues rated the keyword mnemonic as low utility: it is difficult to apply in some contexts and appeared to benefit students for a limited range of materials and short retention intervals. Practice testing and spreading study over time were the two techniques rated high utility.
Recall is not understanding. Knowing that PEMDAS stands for a sequence does not tell you how to handle a fraction inside a bracket. Use mnemonics for the parts of a subject that are genuinely arbitrary.

The practical upshot: build a mnemonic for the list or the vocabulary, then test yourself on the material at spaced intervals. The two work together.

How to make your own mnemonic

Decide what has to be recalled and whether order matters. If it does, use an acrostic, a story or a route.
Make it concrete. Turn each item into something you can see or hear; exaggeration and humour help.
Link the cue tightly to the item. A cue that could stand for several things will fail when you need it.
Keep it short. Several small mnemonics beat one long one.
Test yourself on the real material, not only on the mnemonic, and repeat after a gap of days.

Mnemonic devices and IQ

People sometimes assume that anyone with a remarkable memory must be highly intelligent. The best evidence says otherwise. When Eleanor Maguire and colleagues (2003) studied people known for exceptional memory feats, they reported that the advantage was not driven by exceptional intellectual ability or by differences in brain structure; what set the group apart was that they used a spatial learning strategy, the method of loci. In other words, memory champions are mostly made by technique.

The reverse also holds: learning mnemonics improves memory for what you encode with them, but there is no good evidence that it raises general intelligence. Any claim that a memorisation technique makes you smarter is a claim about transfer, and transfer is the part that usually fails, as our guide on how to increase IQ explains. IQ tests also measure much more than memory, including reasoning, pattern recognition and spatial reasoning.

Trust and scope notes

This page summarises published research for general information, with figures taken from the studies listed below. It is not medical or educational advice: memory problems that are new, worsening or worrying deserve a conversation with a doctor, and no online test can assess them. The IQ Revealed test is an online reasoning test of 40 original items for adults aged 18 and over; it is not a clinical assessment and it does not measure memory. Our guide to how IQ tests work explains what an online test can and cannot tell you.

IQ Revealed is not affiliated with, endorsed by or connected to the researchers, universities, journals or publishers named on this page. Names are used only to identify the research being described.

Mnemonic Devices: 7 Types, Examples and What the Research Shows