Forget rote learning, one of the best ways to commit something to memory is to think of associated images – the more outlandish, the better
If you're revising for an exam, learning a new language, or just keen on maximising your memory for everyday life, here are some strategies that might help …
The brain is often likened to a muscle, the suggestion being that if you exercise it, its function will improve. A bodybuilder can strengthen his biceps by repeatedly lifting weights and so, the argument goes, you can improve your memory by repeating over and over to yourself (either out loud or sub-vocally) the information you wish to remember.
For years, researchers considered that "rehearsing" information in this way was necessary to retain it in your short-term memory and transfer it into long-term memory. This view fits with our instinct that if we want to remember something like a phone number, we say it to ourselves again and again in the hope that it "sticks". Generations of students have held fast to the principle that repeatedly reading through lecture notes and textbooks, attempting to rote learn the facts needed for exams, is the path to success.
There is evidence that the more an item is rehearsed, the greater the likelihood of long-term retention. In one study, participants were presented with a list of words and were asked to rehearse the list out loud. When asked to recall the words, memory retrieval improved as a direct function of the amount of rehearsal that was undertaken. However, in almost all circumstances, simple rote rehearsal is much less effective than strategies that involve thinking about the meaning of the information you are trying to remember.
Although many people imagine that actors memorise their lines using rote rehearsal, research conducted by the psychologist Helga Noice suggests that this is not always the case. Noice found that some actors learn their lines by focusing not on the words of the script, but on their underlying meaning and the motivations of the character who uses them. This is consistent with laboratory evidence – although rehearsing a list of words improves long-term memory for the material to some degree, a more effective strategy is so-called "elaborative" processing, which involves relating the information to associated facts and relevant knowledge. In one study, participants were asked to learn words using one of the following questions:
a) Is the word written in capital letters?
b) Does the word contain two or more syllables?
c) Does the word refer to an item of furniture?
Highest levels of recall were observed following question c, which involves deeper, more elaborative, meaning-based processing.
Another experiment involved participants learning sentences either by simply studying the sentence (eg "The doctor hated the lawyer") or by generating an elaborate continuation to the sentence (eg "The doctor hated the lawyer because of the malpractice suit"). The elaboration method improved memory for the sentence significantly, suggesting that the cognitive effort involved led to deeper encoding of the original sentence.
One study compared different kinds of elaboration to investigate which might be most useful when revising for exams. One group of participants was given topics in the form of questions to think about before reading a text, whereas another group was just asked to study the text. The researchers found that reviewing the text with relevant questions in mind improved retention and subsequent recall of the material.
Indeed, elaborative processing is such a powerful memorisation technique that it appears not to matter whether you are trying to learn the elaborated information. Researchers asked participants to carry out two tasks: checking if a word contained a particular letter, or thinking about the word's meaning. Half the participants thought the true purpose of the experiment was just to carry out the task, whereas the other half were told that they would be tested for recall. The results showed that whether or not people intend to learn is less important than how they process the information.
A visit to any bookshop will reveal myriad self-help books promoting the use of mnemonics as a means of improving your memory. The Method of Loci, perhaps the most well-known mnemonic technique, involves thinking of images that link the information you are trying to learn with familiar locations. So, when trying to remember a list of words, you might imagine walking between the various rooms in your home and in each one commit a word to memory by forming an image that combines the word with a distinguishing feature of the room. For example, if trying to remember the word "apple", you might imagine an apple bouncing on the sofa in your living room. Retrieving the list of words is achieved by mentally walking through the rooms of your house again. One study found that people using the Loci method could recall more than 90% of a list of 50 words after studying them just once.
Mnemonic strategies often lie behind the extraordinary feats of remembering achieved by memory champions such as Dominic O'Brien, the British author and eight-time winner of the World Memory Championships. O'Brien once famously spent 12 hours at a restaurant in London going through 54 packs of randomly ordered playing cards, studying each card once. He then managed to recall 2,800 of the 2,808 cards in the correct order, an astonishing level of success.
The American writer and memory champion Joshua Foer describes in his book, Moonwalking with Einstein, how he learned to use a particularly vivid form of Loci to remember playing cards. For example: "At the front door, I saw my friend Liz vivisecting a pig (two of hearts, two of diamonds, three of hearts) …" Foer's method, which allows him to associate multiple items with each mental location, led him to set a record at the 2006 US Memory Championships by memorising an entire pack of 52 cards in only 1min 40sec.
Techniques such as Loci can be readily adapted to help us remember appointments, birthdays, errands we need to run, etc. As illustrated by Foer's example, the key with mnemonics is creating the most striking visual images possible. The more ludicrous, creative and elaborative you can be, the greater the chance of success.
Evidence suggests that repeatedly testing yourself on the information you have learned can enhance retention considerably. The great memory researcher Endel Tulving was among the first to discover the merits of so-called "retrieval practice". In a number of experiments, participants learned lists of words in three conditions: standard (study, test, study, test); repeated study (study, study, study, test); and repeated test (study, test, test, test). The repeated study group had three times as much exposure to the words as the repeated test group. If learning occurs only when studying, it follows that they should have had better memory. But Tulving found equivalent immediate learning across conditions. However, if retention is measured after a one-week delay, repeated retrieval testing can lead to markedly better recall than repeated studying, even if the studying involves an elaborative learning strategy.
The importance of testing one's memory has been shown to apply to a number of everyday learning situations. The American psychologists Jeff Karpicke and Roddy Roediger investigated the most effective method for learning foreign languages. They found that repeated testing during the learning period resulted in 80% accurate vocabulary recall when examined a week later, whereas strategies used in language study guides saw success rates drop to 30%. Interestingly, when the researchers asked those who took part to predict their later performance, the participants didn't think the repeated testing method gave them any advantage.
This accords with other research indicating that when students are revising for exams, self-testing is a rarely used strategy. If students do self-test, it is often to assess what they've learned, rather than to enhance their long-term retention of the material. Perhaps the fact that repeated study feels less demanding than repeatedly testing yourself leads people to prefer the first approach. However, the evidence suggests strongly that active approaches to learning such as repeated retrieval practice can reap dividends.
• Dr Jon Simons is a cognitive neuroscientist based in the department of experimental psychology at the University of Cambridge. He leads an interdisciplinary research programme investigating the role of brain areas such as the frontal and parietal lobes in the strategic control of human memory. You can follow him on Twitter at @js_simons