The Method of Loci

The method of loci, also called the memory palace, is a way of remembering things in order: you picture each one at a familiar spot along a route you know well, then walk that route in your mind and read them back. Loci is Latin for "places".

It is a 2,500-year-old technology that needs no app, no notebook and no stranger telling you to subscribe for $9.99 a month, only a building you have walked through. On the back of every door and on top of every piece of furniture inside it, you have hung the things you want to remember, and they are yours forever.

This is not a metaphor; it is the technique.

A poet, a banquet, and the roof that fell

Cicero tells the story in De Oratore, written in 55 BCE, and it is already an old story when he tells it.

A Greek poet named Simonides of Ceos has been hired to recite a victory ode at a banquet in Thessaly. He delivers his ode and is paid only half his fee: the host tells him to collect the rest from Castor and Pollux, who shared the praise in the poem. A little later he is called outside by two young men who, the messenger says, would like a word, but they are not there. While Simonides stands in the doorway looking for them, the roof of the banquet hall collapses. Everyone inside is killed, and the bodies are crushed beyond recognition.

The grieving families come to the wreckage but cannot tell which body belongs to which house, so they turn to Simonides (the only living witness to the seating arrangement) and ask him to identify the dead. And Simonides discovers something strange: he can. He closes his eyes and walks the table in his mind, seeing every guest in the order they sat, then points to the rubble at each location and says: this one is yours, that one is hers, and the one over there belongs to the house of the host.

This is the legend, and it may not be true. Cicero tells it as hearsay ("there is a story that"), and Quintilian, writing later, notes that the authorities disagreed about whom the ode honoured and where the house stood, and calls the part played by Castor and Pollux (the twin gods the young men at the door are taken to be) "purely fictitious". What matters is what happens next: Simonides realises that the organisational device of the room itself (the layout of the tables, the position of the couches, the doorway he had stood in) is what carried the memory. The faces were variables; the room was the index.

"He inferred that persons desiring to train this faculty must

select localities and form mental images of the facts they wish to

remember and store those images in the localities, with the result

that the arrangement of the localities will preserve the order of

the facts ..."

- Cicero, De Oratore, II.354 (trans. E. W. Sutton)

That last clause (the arrangement of the localities will preserve the order of the facts) is the entire technique. Two and a half millennia of mnemonics have been variations on it.

What the medieval rhetoricians did with it

For about a thousand years, the Method of Loci was the technology you used if you needed to remember a long thing: not the technology you might use, but the one you did use. Cicero, Quintilian, Aquinas, Ramon Llull, Pietro da Ravenna, Giordano Bruno: they all wrote about it, often at obsessive length, because they needed it. Print was either expensive or didn't exist; speeches went on for hours; sermons had to be delivered without notes; theological disputations could last days. If you wanted to be a public intellectual in the year 1300, you had to have somewhere to put things in your head.

The medieval treatments tend toward the elaborate. Bruno's De Umbris Idearum (1582) describes a memory-system based on celestial mansions that can, in principle, hold the entire structure of human knowledge. Llull's Ars Magna combines loci with rotating wheels of category to generate every possible argument. The Renaissance memory theatres of Giulio Camillo were physical buildings, with marked positions, that were supposed to be loadable directly into the user's mind by walking around inside them.

This is where the technique acquires its reputation as a parlour trick (something that magicians use to memorise the order of a deck, or that record holders use to recite seventy thousand digits of pi). The parlour-trick framing is unfortunate, because it obscures the more important thing about the method: it is the only memory technique we know of that scales. Lists, flashcards and mnemonics that aren't spatial all run out of room, but loci don't, because there is always another corner of the building, and after that another building.

How it actually works

Strip away the medieval wallpaper and the technique is three steps:

1. Choose a place you know cold. That means not a place you've been to once but somewhere you have lived in, walked through hundreds of times, and could draw the floor plan of from memory: your childhood home, your first apartment, or the route from your front door to your coffee shop, every turn.
2. Pick a fixed walking order through it. Whatever it is (front gate, mailbox, driveway, garage door, foyer, coat hook, kitchen counter, fridge, stove), commit to it. The order is the index, and you will refer to it the way you refer to a book's table of contents.
3. At each location ("locus"), place a vivid image of the thing you want to remember. Make it weird, funny or grotesque rather than polite or tasteful, because memory privileges what makes you flinch.

That's it. To recall, you walk the route and find the images at the loci, whose order preserves the order of the things.

As a worked example, suppose you need to remember the first six elements of the periodic table (hydrogen, helium, lithium, beryllium, boron, carbon) in order, for some reason. You walk the route from your front door to your kitchen.

• Front door: a cartoon hydrogen atom (a comically tiny ball with a single electron orbiting it like a fly) is hammering on the door, demanding to be let in.
• Coat hook: a helium balloon with teeth is eating the coats, which is unsettling enough that you will remember it.
• Hallway mirror: someone has scratched the word LITHIUM into it with a key, with a tiny battery scratched in below the word. Lithium powers your batteries; the mirror reminds you who.
• Doorway to the kitchen: a beryl crystal (look up what beryl looks like; pale green, hexagonal) is wedged into the door frame, forcing the door open. Beryl-lium.
• Kitchen counter, where the toaster is: it is full of boron, a brown-black metalloid powder, so you have ruined your toaster.
• Stove: it is, of course, on fire, with charcoal everywhere: carbon.

Now walk the route in your head: front door, hydrogen; coat hook, helium; mirror, lithium; doorway, beryllium; counter, boron; stove, carbon. The route is the order, and the images are the data.

This is, mostly, what every championship memorist alive today is doing. The geometry might be more elaborate (some use phantasmagoric palaces with twenty rooms; some use ten linked buildings in sequence) and the encoding of the data into images might be more sophisticated (PAO for cards, Major for digits, phonetic alphabets for arbitrary syllables). But the substrate (spatial loci, walked in order, with images placed deliberately on them) is unchanged from Simonides.

Building your first palace

Pick a building you know, but not the one you live in now, because you change its layout too often. Choose something fixed in time, where the geometry has stopped moving: the house you grew up in, your high school, the apartment of a college roommate. The fifty memory palace ideas guide lists more, from your commute to the supermarket, with a quick test for any of them.

Walk through it once with intent, without trying to memorise anything yet, the way you would give a stranger a tour. This is the front door. This is the coat closet to the right. The kitchen is through the second door on the left, past the bathroom. Notice which features are sticky (the things that, even after years away, you remember exactly), because those become your loci.

A reasonable first palace has 10 to 20 loci: with fewer you'll saturate quickly, and with more you'll forget loci before you forget the items. Number them, memorise the route, then test yourself: can you recall the loci in order, with your eyes closed, in under thirty seconds? If not, walk it again, because the palace has to be behind the data, not on top of it. To keep the route written down, you can build your own palace here by sketching the floor plan and marking each locus in walking order.

See the six stock palaces →

If you don't have a building you know that well, borrow one. The memory theatres of the Renaissance were, in a sense, an early acknowledgement that not everyone has a personal palace handy. We ship six "stock palaces" on Major Dictionary for exactly this reason: the Tuscan Villa, an NYC studio, an Oxford library, a seaside boardwalk, an archetypal childhood home, and a metro station. Pick the one that feels least like a stage set and most like a room you could imagine being in.

Each stock palace is twelve to sixteen loci in a fixed walking order, laid out on a simple floor plan with one photo of that kind of place, so the route is easy to picture. They are no fancier than the technique requires, since the point is the order, not the rendering.

The five things people get wrong

After two thousand years of writing about loci, the failure modes are well documented, and five keep recurring.

1. Choosing a fictional palace

It is tempting to imagine a vast and cinematic palace (Hogwarts, the Tower of Babel, a spaceship), but resist it. The palace must be a place you have physically been, so that the geometry is built into your motor memory. A fictional palace works for an hour and then dissolves, because there is no off-screen reality holding it together, while a real palace has been there for years and will continue to be there whether you visit it or not.

2. Placing tasteful images

Memory does not privilege tasteful images. The image you place at a locus has to be strange enough that you would tell someone about it. If you are encoding helium and your image is "a helium balloon, floating," that is too tasteful. The balloon needs to be eating something, or on fire, or saying something rude in a French accent. The rule is: the image should be slightly embarrassing to describe out loud. That is the dose.

3. Walking the wrong direction

Your route through the palace is one-directional: you walk it in the same order every time. If you sometimes go "front door → coat hook → kitchen" and sometimes "front door → kitchen → coat hook," you are not using one palace; you are using two, badly. Pick a direction and commit. (Most people walk left-to-right, but the direction matters less than the consistency.)

4. Reusing loci before they're empty

If you put helium on the coat hook for one task, do not put a Latin declension there an hour later. The two images will smear into each other and you will recall a Latin verb for "to balloon." The solution is either (a) to wait long enough for the first image to fade (usually a day), or (b) to keep separate palaces for separate domains. Most serious memorists use a different palace for each type of content: one for languages, one for digits, one for playing-card decks, one for whatever you happen to be reading.

5. Not testing the recall

The technique fails silently if you don't test it. The act of placing an image feels like you've memorised it; the act of walking the route to recover it is where the work is. Within an hour of placing the data, walk the route once and repair any image that has gone faint; that is part of building, not a review. Walk it again the next day, then about six days later and about sixteen days after that, then monthly for anything you want to keep. Spaced repetition explains where those gaps come from.

Variations the championship circuit uses

The simple version above is enough for almost everyone. The championship circuit pushes it in three ways.

Linked palaces. Where a single palace is 10–20 loci, linked palaces chain buildings together in a fixed order, so you walk through one and exit into the next. Top competitors keep dozens of them: Alex Mullen runs about three thousand places across roughly eighty palaces. That is what makes a deck cheap: one deck goes into a single 18-locus route, and the next deck goes into a fresh route that has never held a card, so nothing contaminates anything.

Multi-image loci. Each locus holds a triplet (a Person doing an Action with an Object) instead of a single image. PAO encoding lets you compress three cards into one locus and walk through a deck of 52 in only 18 stops. We unpack PAO in its own article. The PAO method is the canonical treatment.

Encoded substrates. Instead of the headword being the image directly, the headword is encoded into a phonetic-alphabet image (Major System, Dominic, Ben System), so the locus holds the encoded image, not the raw datum. This is what lets memorists encode 200-digit numbers in two minutes: each pair of digits becomes a peg word (via Major), each peg word goes onto a locus, and 100 loci hold 200 digits in a single walk. The Major System explains the encoding.

None of these is a new technique; each is loci with extra machinery on top.

What the research shows

In psychology the method of loci is studied as a mnemonic, and it has been tested both in randomised trials and in brain scanners. Together the studies below point to three things: ordinary people can learn it, the skill was still there four months later in the one trial that checked, and the best memorisers rely on it rather than on unusual brains or a better memory in general. The usual explanation is that human spatial and episodic memory are very large and very durable compared to the working-memory buffer where things-to-remember normally compete for space. By converting an arbitrary list into a spatial walk, you offload the sequencing problem onto a substrate (your memory of a building) that is essentially free.

It works, by a medium margin. The best single summary is a 2021 meta-analysis by Twomey and Kroneisen, which pooled 13 randomised controlled trials, most of them run at universities. The loci method beat the control conditions with a medium effect size (g = 0.65), and the effect stayed at about that size after adjusting for publication bias, the control condition used and the number of training sessions. The authors also flag a weakness: most of the trials did not report how they randomised people or concealed group allocation, so the risk of bias is high. Read it as a solid effect from imperfect studies.

It can be learned in weeks, and it lasts. In 2017 Martin Dresler's group compared 23 of the world's top-50 memory athletes with 23 controls matched for age, sex and IQ, then ran a separate training study on 51 novices. The group that practised the method of loci for forty daily half-hour sessions over six weeks went from about 26 to about 62 of 72 words, far ahead of both an active and a passive control group, and their brain connectivity shifted towards the athletes' pattern. Four months later they memorised a 72-word list again and recalled about 50, against about 30 and 27 for the two control groups (the per-group figures are from a 2021 follow-up by Wagner and colleagues). In the scanner the trained group, like the athletes, showed lower activity in lateral prefrontal cortex while memorising and in parahippocampal and retrosplenial cortex while recalling the order, which the authors read as more efficient neural coding.

The best memorisers are using it, not born with it. The strongest evidence for the spatial account comes from scanning the people who are best at it. In 2003 Eleanor Maguire and colleagues studied superior memorisers, most of them leading World Memory Championship competitors, against matched controls. The memorisers were not cleverer: they scored no higher on tests of general intellectual ability, and their brains showed no structural differences at all. What differed was strategy. Nearly all of them were using the method of loci, and while they memorised, the scans lit up spatial-memory regions including the hippocampus, which is not where you would expect a list of digits to live.

That is better news than a brain difference would have been. A structural advantage is something you either have or you don't, whereas a strategy is something you can be taught in an afternoon and then spend years getting good at. It also sets the ceiling honestly: the same study found the memorisers beat controls on digits and faces but not on abstract snowflake patterns, which are hard to walk past on a route because there is nothing in them to picture.

You are not making your memory better; you are taking a job your memory is bad at (remember this list of fifteen things in order) and transforming it into a job your memory is good at (remember a walk through your grandmother's house). The method is a translation, not a magic trick.

This is why the technique has lasted: it depends not on anyone being unusually clever but on the architecture of human memory, which is, on a long enough timeline, more reliable than fashion.

Where to start

The apartment, house or route to work that you know cold is your first palace. Pick six points along it, walk the route once with intent, then try to memorise a grocery list of six things at those six points, with images that would slightly embarrass you to describe.

Then walk the route an hour later, the next morning, and about six days after that. The grocery list will still be there, and so will the palace. You have just learned a 2,500-year-old technique that the internet cannot delete.

If you want a starter palace already laid out, the six above ship with Major Dictionary, illustrated, annotated, and free to adopt. Pick whichever one your inner eye already knows the best, then walk it without thinking. The architecture is doing the heavy lifting; you are renting the loci.

See also: The Major System for encoding numbers into peg words; Person · Action · Object for three-image loci.