​Learning mnemonics boosts memory and triggers lasting changes in the brain

Memorize 550 numbers in five minutes. Master a new language in a week. Recite thousands of digits of Pi, all without breaking a sweat.

Go to the profile of Shelly Xuelai Fan
Apr 10, 2017
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Memorize 550 numbers in five minutes. Master a new language in a week. Recite thousands of digits of Pi, all without breaking a sweat.

These astonishing feats of memory may seem impossible to the average Joe, but to a small handful of memory athletes, they’re all in a day’s work. Like any other type of athletes, those that compete in the annual World Memory Championships credit their success to hours of practice, often using an ancient mnemonic technique called the Method of Loci. But scientists still wondered: is it all practice, or do these memory elites have a brainy advantage?

Now, a new study published in Neuron gives all of us hope. Superior memory can be learned in as little as six weeks with diligent practice, while triggering long-lasting, wide spread changes in brain activity so that it resembles that of a memory athlete’s.

Scientists have long wondered how learning changes our brain. A previous study with London cab drivers showed an increase in the size of their hippocampi—a brain region linked to spatial memory—as they learned to navigate the city’s convoluted streets. But brain changes can also be subtle, not showing up as anatomical differences, rather as how reliably different regions communicate.

In the first experiment, the researchers recruited 23 memory athletes from the Top-50 world rankings and carefully selected control volunteers with similar age, gender and IQ. The volunteers were given some brain scans under two conditions: first, while they were relaxed and letting their minds wander, and second, while they were trying to memorize a list of 72 words.

True to their name, the memory champions missed only two words on average when recalling the list 20 minutes later, whereas their controls missed nearly half. Although the brains between the two groups weren’t noticeably different, the memory champions did show different patterns of brain connectivity under both conditions. This made the researchers wonder: can these connectivity patterns explain superior memory performance?

To dig deeper, the team randomly separated the controls into three groups: one was asked to practice the Method of Loci for half an hour every day for a total of six weeks. The method, first developed by the ancient Greeks, involves picturing yourself walking down a familiar road and depositing things you need to remember along the way. To recall, just imagine going down the same road again, “picking up”
your “anchored” memories.

Another group practiced a very challenging memory task, the dual N-back, in which they had to memorize a sequence of spoken words while paying attention to the locations of a moving square on the computer screen, and identify when a letter or position matches one that appeared earlier. The last group had it easy—they just relaxed for six weeks.

When tested right after training, only the Method of Loci group showed improved memory (at least for a list of random words). Although their brains didn’t physically change, their connectivity patterns had morphed during the course of training, becoming more similar to those of memory champions. What’s more, this shift in brain connectivity predicted their performance in the memory test—something really exciting, because it suggests that altered activation patterns might underlie their better memory.

What’s more, the changes persisted for at least four months afterwards, as did the participant’s improved memory, suggesting that the effects stuck around.

Previous studies have shown that using the Method of Loci activates brain regions involved in visual and spatial memory; namely, the hippocampus and surrounding regions. This really isn’t surprising, since the technique requires imagining moving through space. The latest study corroborates those results in both veteran memory champions and the newly minted super-memorizers.

But in addition to local changes, the study also found increased connectivity in the brain’s default mode network (DMN)—a sprawling collection of brain regions that comes online when we’re focusing on our internal thoughts, rather than the world around us (as some would say, daydreaming). This network is so enigmatic that it has been dubbed the brain’s “dark energy”, and scientists still aren’t quite sure what its functions are, although it seems to be involved in cognition and creativity. Why learning the Method of Loci—but not the mentally challenging dual N-back—stimulates the DMN remains a mystery.

This study is a jaw-dropping demonstration of our brain’s amazing plasticity, but it also raises a lot more questions. Are the brain connectivity changes specific to learning the Method of Loci, or would other mnemonics also induce the same pattern? Are these connectivity patterns also present in people born with incredible memory abilities? And why didn’t the dual N-back, an awfully challenging task, also give memory a boost?

But one thing is clear: a superior memory is accessible to all of us, given enough practice and using the right methods. Just don’t fall for any “brain training” app you see out there—you’ve got a science-approved one right here.

References:

Dresler, M., et al (2017). Mnemonic Training Reshapes Brain Networks to Support Superior Memory. Neuron, 93: 1-9.

For those interested in learning more about the Method of Loci and memory athletes, I highly recommend Moonwalking with Einstein by Joshua Foer.

For those interested in the default mode network, Ferris Jabr has a great piece on Scientific American MIND here.

Go to the profile of Shelly Xuelai Fan

Shelly Xuelai Fan

Neuroscientist, UCSF

I study how aging and exercise changes the brain.

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