Spend enough time watching fictional geniuses on television and you will undoubtedly see the trope of the mind palace. Brainiacs, we are told, have mind palaces, ornate libraries that live solely in the mind, cataloguing their exceptional knowledge.
On the BBC show Sherlock, which was a popular modern reinvention of the classic character, Holmes was seen going through what the writers assumed a mind palace would look like while solving a case. Another episode had the villain of the week, another super-genius (the show was full of them), storing blackmail in his own mind palace, which was portrayed as a massive library. And who could forget Hannibal, the show about Hannibal Lecter and the people with whom he toys, in which really smart characters could escape their surroundings by spending time in meticulous, imaginary recreations of favourite places?
Mind palaces are real, but they are nothing like their depictions on screen. They can improve your memory. They can propel you to a niche form of stardom. Yet, when scientists have tested various aspects of this memory technique, they have realized that everything we thought we knew about it is probably wrong.
In the first place
The memory palace as a technique to remember things is not new; it comes from hunter-gatherer communities, although it is usually credited to the Greek poet Simonides of Ceos, who was born in approximately 556 BCE. As with all origin myths, the story which follows should be taken with a large grain of salt.
At a reception held for a nobleman, Simonides was chanting a long poem, which is what you did before the invention of the comedy roast. The nobleman was annoyed by the fact that half of the poem was dedicated to praising the gods Castor and Pollux, so he told Simonides to go and ask them for half of his performance fee. There was a knock at the door: two young men wanted to see Simonides outside (presumably the gods in disguise come to interfere in the affairs of men). Simonides left the banquet hall and its roof collapsed, killing everyone inside. The bodies were mangled beyond recognition, but Simonides remembered where they were all sitting and was able to identify the corpses. This gave him the idea for the mind palace.
Each person had been sitting at a particular place. The word “place” in Latin is locus in the singular, loci in the plural (usually pronounced “low-seye”). This is why, when trying to avoid the grandiosity of the phrase “mind palace,” we usually refer to this technique as the method of loci. It’s a simple technique. Imagine I’m going to the grocery store and I want to remember to buy a bag of apples, a loaf of bread, and a roll of aluminum foil. Importantly, I want to remember them in this order, because I know the layout of the store and I want to be efficient with my time.
I can use the method of loci to do this. The trick is to plant these items along a known path in my mind. I can visualize, for example, the path I take getting out of bed and walking into my kitchen. On this path, I identify specific places (or loci) where I will drop the items I want to remember. The first thing I see in bed is my alarm clock. That’s my first locus. I want to imagine a bag of apples near my alarm clock, although many fans of the technique will recommend you come up with a particularly bizarre image, as it’s thought to stick better in your memory. I could imagine a stack of apples on my night table, and they all have clock heads and those metal bells found on old alarm clocks. Apple clocks. That’s a striking image. Next, I get out of bed and see the door to my bedroom. That’s my second locus. I need to combine it with a loaf of bread somehow, so I imagine that my door is a giant slice of bread on hinges. The third locus is my kitchen counter, and I imagine it is covered in aluminum foil.
Once I have committed these bizarre images to memory, I go to the grocery store and I retrace these imaginary steps in my mind. As I see the apple clocks, I pick up a bag of apples in the store. I then see the bread door, so I add a loaf of bread to my basket. And when I see the aluminum paper countertop, I go to the right aisle and pick up a roll of aluminum foil.
The path I commit to memory—from my bed to the kitchen, in this case—can be any path I’m familiar with. It can be the ride from home to work. It can be my favourite running route or biking trail. It can, yes, even be an opulent Italian palace that you just so happen to know like the back of your hand because you’re Hannibal Lecter. The important thing is to create interesting places along this path on which you can pin the things you are trying to remember.
The method of loci, also called the memory journey or the mental walk, was a favourite of Ancient Greek rhetoricians, who couldn’t rely on PowerPoint slides to guide them through their speech and thus memorized the points they wanted to make using this memory trick. It is one of the oldest mnemonics, meaning a method or device designed to improve your memory. It is commonly used by mnemonists to remember very long lists of numbers or the order of a randomly shuffled deck of cards as a party trick. Many people who can remember tens of thousands of decimals for the number pi do so by using the method of loci. They first associate each digit with an image or letter, and they plant these images or letters in the right order along a mental path. The current Guinness World Records holder managed to recite the first 70,000 decimals of the number pi over the course of ten hours. (Bigger claims have been made, such as one for 100,000 decimals, but they were not verified by Guinness.)
It would be easy, especially as a TV writer, to make all sorts of assumptions about the method of loci. That only super-geniuses can harness this method to create incredible mind palaces. That using this technique requires sight, a fantastic imagination, and a great sense of orientation through space. That the method of loci necessitates a path.
It would be easy, but we would be wrong on all accounts.
An off-the-peg method
You do not need to be some writer’s idea of Sherlock Holmes to benefit from the method of loci. In fact, there’s something quite egalitarian in the technique, in that anyone can use it to better memorize lists of things given enough training. The people who win championships performing spectacular feats of memory have been studied. They’re not smarter than the average person and they don’t have unusual brains. They simply train their brain in the method of loci the same way that a professional athlete trains their body. You too can have a mind palace, although it will more likely look like the streets in your neighbourhood and less like a posh Victorian library.
As a mnemonic, the method of loci is effective. The people performing memory stunts are proof enough, but it has also been studied. A meta-analysis was recently published which summarizes the 13 randomized clinical trials dedicated to teaching participants this method and testing them to see how much better they are at committing lists to memory compared to controls. Participants in these control groups were either given no instructions on how to memorize these lists or were told to use different techniques, depending on the study. The benefit of the method of loci was clear and wasn’t small, though there were issues with the studies themselves, notably the fact that they are almost all conducted on young students getting a degree in psychology. In the elderly, a tiny number of studies have been published, and while they are promising, their size and quantity don’t allow for as much confidence. Another issue with studies of the method of loci is that both the training and testing tend to happen the same day. A 2021 study did a four-month follow-up and the results were encouraging, but the long-term benefits of training in the method of loci will need to be explored further.
Whether or not coming up with bizarre images truly gives you an advantage—what a professor once referred to as “the conscious use of artifice”—seems to be an unresolved question at the moment, with a number of studies arguing that there is no advantage to creating strange images instead of more banal ones. But surely the basic ability to visualize things in the mind is important, right? Apparently not, as people born blind can perform just as well as sighted individuals using the method of loci (as cited here). Researchers from the University of Alberta report that there is controversy right now over whether or not you need good visuospatial skills to benefit from the mind palace. This is the brain function that allows us to identify shapes and spaces in two or three dimensions, which comes in useful when assembling furniture or driving a car. Some brain imaging studies of people using the method of loci show these areas lighting up, but other findings cast doubt. I would be curious to know what goes on in the head of an aphantasic—someone who cannot visualize things in their mind easily or at all—while using the method of loci.
Equally surprising is the body of work of this same team in Alberta showing quite elegantly that the path used in the method of loci is not even necessary. In one study, they showed participants one of three virtual environments to use for the method of loci: an apartment, an open field, and a maze that looks like a sun with rays emerging from it. Differences in performance between the three environments were quite small, despite the fact that the field, for example, had no clear path between loci. In another study, some people were told to use parts of their own body as loci: that bag of apples could be linked to my left foot, with the bread tied to my thigh and the aluminum foil making a makeshift bathing suit, for example. These people did as well as the ones using the traditional method of loci, which traces a clear, one-way path through the loci. The researchers have argued that the memory benefits of using the method of loci may have little or nothing to do with the path itself and everything to do with the loci. This would make it a variant of another mnemonic, the peg method, where numbers are associated with images to create loci, which can then be combined with the items that need to be memorized. With the peg method, there is an order but there is no path, no road down which the person needs to walk in their mind.
The question I kept asking myself as I was reading these papers, though, was, “how useful is the method of loci these days?” Unless you are giving a TED Talk, you can remember your speech by relying on your slides, and a trip to the grocery store can be improved by carrying a list on your phone or on a piece of paper. Academics who study the method of loci often argue that more students should learn it and use it, but how many memorization tasks in school require learning items in a precise order? I’ve seen some suggest using the technique to memorize the order of the cranial nerves in medical school, but coming up with a memorable image for the trochlear nerve and the hypoglossal nerve is certainly going to be a bigger challenge than memorizing a grocery list. There are also quicker and easier alternatives to committing biology to memory. Phrases like “Dear King Philip Came Over For Good Sex” to remember biological taxonomy (domain, kingdom, phylum, class, order, family, genus, and species) is easier to remember that a complicated method of loci.
For now, the memory palace technique will remain a tool mostly used not by geniuses trying to solve crime but by people who want to challenge themselves and show off just how many decimals of the number pi they can fit inside their head.
Take-home message:
- The mind palace technique or the method of loci is an ancient way of helping you remember a list in a precise order
- It works by memorizing a path, like your ride to work; identifying specific and distinct places along this path; and putting the items from the list in these places, creating memorable images along the way
- Research into the method of loci has shown that even blind people can do it, that the ability to navigate through spaces in your mind may not be important to the success of the method, and that the path itself is not necessary
