Imagine the route you typically take to the grocery store. Now imagine the many identifiable landmarks that exist between your home and the store — like a specific garden, stop sign, or gas station.
Take these landmarks and associate them with things you’re trying to remember, such as the items on your grocery list. So for the garden, let’s assign mustard. For the stop sign, we’ll add ketchup, and for the gas station, we’ll use relish. Once at the grocery store, you’ll be able to recall these items simply by re-imagining your trip to the grocery store and the associated landmarks.
This mnemonic, called the “method of loci,” has been around for centuries, and it’s surprisingly effective. New research published in Science Advances on Wednesday suggests this technique is good for both short-term memory and also long-term recall. What’s more, the method of loci rewires the brain, allowing for the improved storage and retrieval of long-term memories, according to the new findings. The study was led by neuroscientist Isabella Wagner from Radboud University Medical Centre in the Netherlands.
“It is so effective that memory athletes, those who train and have superior memories, use them, too,” Jeni Pathman, an assistant professor at York University in Toronto, explained in an email, referring to the technique.
This method, which dates back to ancient Greece, works well because it allows us to use well-known places or routes that serve as a kind of “scaffolding,” as Wagner explained in an email. This lets us embed new — but completely unrelated information — onto a “structure” we already know, she said.
“Moreover, it definitely helps to form unusual, novel, or even bizarre associations that capture attention,” Wagner said. “The combination of prior knowledge and novelty is very powerful to boost memory.”
That the method of loci is good for short-term recall is well known, but its effect on longer term memories is poorly understood, as is the effect of this technique on the brain. To find out, Wagner and her colleagues recruited 17 leading memory athletes — all experts in the method of loci — and 50 non-experts. These 50 individuals were assigned to three groups, one that went through a rigorous six-week training course in the method of loci, a group that received working memory training, and a group with no memory training at all.
“We wanted to see whether novices could train the method of loci to such an extent that they would reach performance levels close to actual memory champions, and also whether their brain processes become similar to those of champions with training,” explained Wagner.
All participants were put through fMRI scanners both before and after training, which was done to assess their memory performance and study brain function.
With brain scans, scientists can “indirectly image the activity of neurons in the brain,” allowing them to identify regions that are “engaged during studying new information, during remembering, or during rest, which is important to stabilise information in the brain for a longer term,” said Wagner, to which she added: “This is also why a good night of sleep or a nap are very important!”
In terms of the memorisation task, participants were asked to memorise lists of random words. They were then shown word triplets, that is, three words at a time, and asked if the words were presented in the same or different order compared to how they appeared during training.
Four months later, the participants were administered the test to see if they were still able to recall some of the memorised words from the training sessions. The method of loci group recalled 50 words on average, the working memory group recalled around 30 words, and the untrained group just 27 words on average.
“Performance was still remarkably good after four months, showing that participants were still able to successfully utilise the method of loci to improve their memory,” said Wagner. “This was not super surprising to us, since we already hoped that training would have a long-lasting effect.”
Analysis of the brain scans showed decreased activity in the lateral prefrontal, posterior parahippocampal, and retrosplenial cortices — areas associated with task-based activation. By “task-based activation,” the scientists are referring to brain processes that are happening during the studying and remembering of random word lists. This was observed in both memory athletes and the non-experts that received training.
“We found that training led to decreased brain activation in regions that are typically engaged in (spatial) memory processing and that are important for long-term memory,” explained Wagner. “This was somewhat surprising to us, as better performance is typically associated with increased engagement of different brain regions. What we saw here is the opposite: training decreased activity in these regions so that lower brain activation leads to better memory.”
This could be interpreted as “neural efficiency,” she said, as less resources might be needed to achieve improved performance.
At the same time, the training resulted in the boosting of neural connections between the hippocampus and cortex. This helps with the storage of memories for the long term, which could explain why the participants’ recall was so good four months later.
“This study is important because, not only did it show that regular people can practice using this technique to create long-lasting memories, but it showed how it can affect their brains,” Jeni Pathman, an assistant professor at York University in Toronto, said in an email. “Those that were in the memory training group showed activity in the brain during learning and remembering that was more similar to memory athletes.”
Pathman’s only complaint was the relatively small sample size, which she said is “understandable given the nature of this work.” In terms of required future work, Pathman said it would be “important to extend this study about creating long-lasting memories to other age groups or to groups that may have more trouble with memory,” as they might be able to benefit, too.
Indeed, the method of loci could be of assistance to people with age-related cognitive decline, but future research will have to suss that out. For now, we can leverage these new findings as we garden, stop sign, and gas station our way through the grocery store.