The World Memory Championships were founded in 1991 by Tony Buzan and Raymond Keene. Since then, competitors have memorised thousands of random digits, hundreds of names and faces, and entire shuffled decks of playing cards — in minutes — using a technique that dates to ancient Greece.
The method of loci is not merely one technique among several at the World Memory Championships. It is the foundation of almost every competitor's system. Understanding how memory athletes use and adapt it reveals both the power and the depth of what the technique can achieve.
Maguire et al. (2003): memory champions have normal brains
The most important finding about memory champions came from a 2003 paper in Nature Neuroscience by Eleanor Maguire and colleagues at University College London.
The researchers recruited ten of the UK's top-ranked memory competitors — including participants in the World Memory Championships — and ten matched controls (same age, sex, IQ range). They scanned all 20 participants' brains using structural MRI and gave them memory tasks while monitoring brain activity with fMRI.
Structural MRI showed no significant differences between the two groups in any brain region. Memory champions do not have larger hippocampi, denser grey matter, or unusual brain architecture. Their brains are normal.
Functional MRI during the memorisation tasks told a different story. Memory champions showed greater activation in:
- The hippocampus (spatial memory and navigation)
- The medial parietal cortex (spatial imagery)
- The lateral occipital complex (visual imagery)
Controls, using their natural strategies, showed greater activation in regions associated with verbal rehearsal and working memory. Champions had simply shifted their entire encoding strategy from verbal rehearsal to spatial-visual imagery — and the brain activity reflected this.
The conclusion is direct: elite memory performance is a strategy, not a gift. The gap between a memory champion and you is a technique, not a brain.
The standard palace system at competition level
At the World Memory Championship, the principal event is the "Speed Cards" discipline: memorise one shuffled deck of 52 playing cards in the fastest possible time. The current world record is under 13 seconds. In the "Hour Cards" event, competitors memorise as many decks as possible in 60 minutes — top competitors exceed 28 decks (1,456 cards).
The system used universally at elite levels:
Step 1: Card-to-image encoding
Each card is pre-encoded as a vivid image before the competition begins. This is typically done using the Person-Action-Object (PAO) system or its variants. In PAO, every card maps to a specific person, that person's characteristic action, and a distinctive object:
- 3 of Hearts → Barack Obama (person) riding a bicycle (action) holding a clipboard (object)
- 7 of Spades → Marilyn Monroe (person) singing (action) holding a candle (object)
This system is learned over months or years and becomes automatic — the player sees "7 of Spades" and immediately sees "Marilyn Monroe singing with a candle."
Step 2: Grouping cards into palace images
Cards are processed in groups of three. Each group of three cards generates a single, compound image: the person from the first card, performing the action of the second card, using the object of the third card. Three cards become one image.
52 cards → approximately 17–18 images.
Step 3: Placing images in a palace
A 52-card palace has at least 18 stations. Each image is placed at one station. The entire deck is "stored" in 18 vivid scenes along a familiar route.
Recall is the reverse: walk the route, see each scene, decompose it into its three constituent card images. The order is preserved by the palace's spatial order.
This system — card encoding + grouping + palace placement — is why the records exist. No individual with superior innate memory is needed. The system is learnable by anyone.
Dominic O'Brien and the Dominic System
Dominic O'Brien won the World Memory Championship eight times between 1991 and 2002 and is widely credited with professionalising the discipline. His Dominic System (a number-to-person encoding system) became the template for most modern competitor systems.
In the Dominic System, each pair of digits (00–99) is assigned to a specific person using initials: 1=A, 2=B, 3=C, 4=D, 5=E, 6=S (six looks like S), 7=G, 8=H, 9=N, 0=O. So 14 → D (1) + D (4) → DD → any famous person with initials DD: Donald Duck, Doris Day. Each person has a characteristic action.
A sequence of 100 random digits becomes 50 person-action pairs, placed in 50 locations along a palace route. O'Brien walks the palace to recall them.
O'Brien has been public about his use of memory palaces throughout his career, writing several books on the technique (How to Develop a Brilliant Memory Week by Week, You Can Have an Amazing Memory). His advice for beginners: start with a single room, encode 10 items, test immediately, and expand only after consistent success.
Ed Cooke and Memrise
Ed Cooke is a two-time World Memory Championship Grand Master (the title for anyone who has memorised a deck of cards in under two minutes, 1,000 random digits in an hour, and 10 decks of cards in an hour). He is also a co-founder of Memrise, the language-learning platform that integrated memory palace principles into spaced repetition software.
Cooke is notable for making the techniques accessible — he coached journalist Joshua Foer to win the US Memory Championship, a process Foer documented in Moonwalking with Einstein (2011), one of the most widely read popular accounts of memory palace technique.
Cooke's pedagogical contribution was identifying and articulating the key encoding insight: the image must be surprising. Not merely vivid, not merely bizarre — but specifically unexpected. The cognitive load associated with surprise ("I didn't expect that") creates an enhanced encoding signal. His concept of "mem" — the minimum surprise needed to create a durable image — has influenced how the technique is taught.
Ben Pridmore and the Ben System
Ben Pridmore, three-time World Memory Champion, developed his own encoding system (now called the "Ben System") that is arguably the most sophisticated in competitive memorisation.
The Ben System encodes groups of three playing cards as a single image, using a set of 52 × 52 × 52 = 140,608 possible person-action-object combinations. Rather than using a small set of memorable figures (as in PAO), Pridmore developed unique images for the combination of all three cards simultaneously — a system that takes years to learn but allows faster encoding at elite levels.
Pridmore's palace use is intensive: for "Speed Cards," he uses a highly familiar route (the streets near his childhood home) with stations spaced exactly at well-known landmarks — his school gate, the corner shop, the church — allowing near-automatic placement.
His public description of the encoding process emphasises the importance of movement: images that move, interact, transform, and cause effects are more durable than static images. A sword resting against a wall is a prop. A sword swinging and cutting through a bookshelf, sending books flying, is a scene.
What non-champions can learn from these techniques
The memory sports community has refined the method of loci under competitive pressure over three decades. The key lessons for everyday users:
Pre-encode your subjects: Memory champions spend months learning their card-to-image system before competing. For academic use, this means building your vocabulary of images — a standard cast of vivid characters and objects — before study season begins. The pre-encoding work pays off enormously during revision.
Density is the enemy of accuracy: Champions use large palaces with well-spaced stations. The single most common beginner mistake is cramming too many items into a short route, causing stations to blur together. If a palace has 10 stations, it should cover a physical distance of at least 50–100 metres of mental walking.
Movement beats statics: Every elite competitor emphasises animated, dynamic imagery over still scenes. The action of an image is often more memorable than the image itself. When creating images, prioritise the interaction — what is the image doing to the station?
Test under pressure: Memory champions train themselves to retrieve under time pressure and audience scrutiny. This pressure-testing is itself a form of retrieval practice that strengthens the palace. For students, this means regularly testing your palace under exam-like conditions — timed, silent, without notes.
The Mind Palace Builder tool lets you practise with famous landmarks used by many memory athletes for training — the Eiffel Tower, the Colosseum, Stonehenge. The Mind Palace course covers the encoding principles used at competition level, adapted for everyday academic and professional use.
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