Let’s try a small thought experiment. Take a minute to think back to your science classes in high school, and see how much you can recall.
Can you explain the elements that make up an atom, or the basic principles of plant biology? How about physics, or simple chemistry? Do facts and procedures come rushing back, or do you remember your teacher’s face, or the way the room smelled after an experiment?
Everyone will have a different set of memories, and they may have very little to do with what you were taught in class. You mightn’t remember anything at all. It’s extraordinary how quickly we manage to forget what we crammed during all those long hours of study. Algebra. Long division. Verbs, adverbs and relative clauses. The causes of World War I. Where did it all go, we muse, years later?
It is extraordinary that so many of the world’s education systems, which are usually based on testing how well a student can recall and apply information, should be designed without any real thought of how our memories work. Memory is perhaps the most fundamental factor in how human beings learn. It should inform all aspects of education; instead, it’s an afterthought.
Ask any teacher and they’ll tell you about a class where the students seemed to completely master a topic, and yet after a couple of weeks they had forgotten it. “But they knew it last week!” comes the cry of dismay. Curricula are often designed to repeat year on year: you do fractions in Grade 5, and then a year later in Grade 6, by which time you’ve forgotten most of what you learned the previous year.
Advances in cognitive science have huge implications for how we learn and remember things. It’s time for policymakers, educators, and anyone who wants to learn something — in other words, all of us — to start listening.
IT’S GOTTA BE IN HERE SOMEWHERE
Imagine a large, dusty storeroom that contains all the things you’ve ever learned. This is what Robert Bjork, psychology professor at Stanford, calls storage space. Your phone number, the Spanish word for cat, the route to get back home from the pub after you’ve had one too many — all these memories are kept inside the storeroom.
So when you try in vain to recall something, the problem is not that you don’t know it. It’s a question of the retrieval strength of the memory: whether you can access it or not. You can remember your current address because it has both high retrieval strength and storage strength, but might struggle to remember your old address because although you knew it well once (high storage strength), you haven’t activated that memory in years (low retrieval strength).
So if you really want to remember something, you need to have it well lodged in your storeroom, and know where to find it when you need it. A lot of research in the Bjork Learning and Forgetting Lab centers around “desirable difficulties,” the gist of which is that if something is initially difficult, you will actually learn it more deeply, and be able to recall it later on. Desirable difficulties include spacing, where you study in chunks rather than all in one go, testing rather than re-studying the same material, and varying the conditions of practice instead of keeping them constant.
WILL THIS BE ON THE TEST?
Picture the scene, the night before a big exam: coffee, notes, a faint air of panic, cramming, cramming and more cramming.
This is a perfect example of how not to learn something. One of cognitive psychology’s most robust findings, demonstrated consistently in a variety of contexts, is the importance of spaced repetition. If you want to learn something, do it in chunks over a period of time. Each time you access that memory again you are increasing its storage strength. But don’t just read over your notes: test yourself with a short quiz or try to explain what you’re learning to a friend. Frequent low-stakes testing can be really helpful as both a diagnostic tool (to check if you’ve really understood something) as well as an aid to memory.
The spacing intervals are important. Increasing the intervals between learning sessions, and thereby reducing the accessibility of information, actually fosters deeper learning. When you struggle to remember something that you learned a few days ago, you’re forced to work hard and engage with the material more. So you might study something on Monday, do some follow up on Tuesday, take a quiz on Thursday and then another quiz the following week. The gaps between study should initially be small and gradually increase. You want the memories to be difficult to access, but not impossible (there’s no benefit to studying things a year apart).
But what if time is of the essence? Bjork’s findings suggest that interleaving can actually mimic the benefits of spacing. This is where you chop and change what you’re learning. By interspersing different elements, you are effectively “reloading” each time, forcing yourself to learn new strategies to retrieve information. A random order is best.
GET IN THE CUE
Neuroscientist Daniel Willingham calls memories “residues of thought.” But simply thinking about something is not necessarily enough to create a memory. Why do we remember the things we do? You might remember a beautiful, quaint old ice cream parlor you visited last summer, but not the flavor of ice cream you had. Why would you remember one aspect but not the other?
Much of what we remember is not a result of conscious effort. We remember the aspect of an experience that we think about the most. So if you see a barking dog while going for a stroll, you might think about the sound of the bark, or how the dog looks, or you might wonder if it’s annoying for the neighbors. How you think about the experience will shape that particular memory.
Everyone has had the experience of visiting a place they knew as a child, and having memories flood back. Cues are what help us retrieve memories. The creation of specific and detailed cues is the key to remembering things, and Willingham argues that missing or ambiguous cues are a major reason why we can’t recall something. He cites an example of saying to a friend, “Here’s that $20 I owe you,” and the friend saying “You don’t owe me $20.” A better cue would offer more information, like: “Remember, we were at Macy’s and I wanted to buy that shirt, but their computer wouldn’t take my card so I had to borrow cash?”
Let’s try another little experiment. Look at the following list, and then look away and write down the items. Have a friend read the list to you, if possible.
apple, blueberry, grape, orange, raspberry, watermelon, fig.
Did you get most of them? Probably. Your mind instinctively says “This is a list of fruits that I just heard.” Now do the same for this list:
apricot, banana, peach, pear, grapefruit, blackberry, plum.
If you didn’t get as many, there’s a reason for that. The cue, “a list of fruits that I just heard,” becomes crowded with correct words (from this list) and incorrect words (from the previous list). If you do a third list of fruits, chances are you will remember even fewer of them. But this one should be easier:
Doctor, soldier, firefighter, teacher, chef, secretary.
With this list, your mind is able to form a new cue, different and unambiguous. Recall improves.
THINK OF A PARTICULAR DUCK
Willingham identifies several tricks to create good memory cues:
Have you ever studied music? If so, how do you remember the lines of the treble clef? My piano teacher taught me that Every Good Boy Deserves Fruit (E-G-B-D-F). When I get east and west mixed up, I remind myself to Never Eat Soggy Weetbix. This method is known as acrostics. Similarly, we can use acronyms, such as HOMES to indicate the great lakes (Huron, Ontario, Michigan, Erie, Superior).
Language learners tackling foreign vocabulary might want to use keywords. If we look at the Spanish word for mushrooms, champiñones, we can see it is very similar to the English word champions. To make a memory cue try visualizing a champion boxer, arms held aloft in the ring, with mushrooms on his hands instead of boxing gloves.
Music and rhymes are extremely powerful. No doubt you can recall childhood nursery rhymes and chants, and probably a few advertising jingles as well. Songs and chants are predominantly used with young children but are also very effective for adult learners.
Mnemonic associations are best for more abstract things. What if you can never remember if a school administrator is a principal or principle? Just remember that she’s your pal. If you’re learning devnagri (Hindi) script, you might think that the symbol for ja, ज, has a hook which would be a good place to hang a jacket. It’s best if these cues are personalized, bizarre, memorable, and specific. Willingham argues that if you want to create a visual image of a duck, “you must think of a particular duck. You must specify its size, proportions, coloring, posture, etc. All of these details make the duck more distinctive, and thus less likely to be confused with other ducks, and therefore a better cue to the target memory.”
Finally, here are a couple of less well known suggestions if you have to remember a list. One is using pegwords. First you make up some simple rhyming pegwords like “one is a bun, two is a shoe, three is a tree.” Then if you’re trying to memorize “onion, duck, artist,” you could picture a sad man holding a bun with only onions in it, a duck trying to climb a ladder while wearing oversized shoes, and finally an artist falling out of a tree.
Perhaps the oldest mnemonic device is the method of loci or “memory palace” technique espoused by the Greeks and Romans. This involves creating a kind of mental geography — say a walk from your front door out to the street — and using strong imagery to link certain words to key points along your “mental walk.” Again, bizarre and distinctive imagery works best.
Before you rush off to study at spaced intervals, creating clever mnemonic cues to help you with your Italian verbs, one final word of warning.
We constantly overestimate how well we know something. Feeling like you know something is not a very accurate guide: both children and adults consistently “think their learning is more complete than it really is,” according to Willingham.
His rule of thumb is to study until you know the material — and then keep studying, for about another 20% of the time you’ve already spent. In other words, because we overestimate our knowledge, we should overlearn by about 20%.
The latest in curriculum design from the UK, “mastery curriculum,” is heading in this direction. Its principles include spending more time on fewer subjects, interleaving topics so that learners encounter them early on and then are exposed to them repeatedly over time, and using frequent low-stakes testing, spaced out over varying intervals, to stimulate deeper learning and recall. Babbel and other educational apps also incorporate spaced repetition practices and short quizzes to aid memory retention.
In a world where the importance of human memory seems to be ever diminishing, our understanding of the crucial role of memory in learning is moving in quite the opposite direction.