Jim Triolo, ’35, MA ’36, remembers the score of each Big Game for the five years he was at Stanford. He remembers orchards and pastureland surrounding the campus for miles, and the smell of the sheep that clipped the athletic fields in the 1930s. He recalls planning campus political strategy among the haystacks behind the eating clubs, plotting the course that would elect him class president. With so little nightlife to be found around the Farm, he and his classmates made their own entertainment, improvising “jolly-ups”—after-dinner dances to radio music.
Triolo remembers the names of everyone in his class. Yet he sometimes forgets where he parked his car, and he struggles to come up with many names of people living in his retirement community in Cupertino.
Such is the peculiar nature of memory. Memories of the long-ago past can seem vivid and immediate, while something that happened yesterday or today can be devilishly difficult to recall. As Triolo and many others have found, our ability to form new memories and retrieve them declines as we get older. This is not dementia, but a natural part of aging.
Memory gaps can be merely a bother, or they can be so pervasive that people feel they are losing their competence or even their mind. Either way, when forgetfulness strikes, it forces us to realize how much of what we do depends on memory. That’s because, at every moment of our lives, we are navigating a sea of memories. Every time we perceive something or have a thought, the brain makes sense of it by putting it in context, comparing it to past perceptions and thoughts. In many ways, we are our memories, defined by all that has happened to us before. So, by enriching our memory, we enrich our lives.
Helping people do that is the aim of a husband-and-wife research team at Stanford. Psychiatry professor Jerome Yesavage, MD ’74, and memory-training specialist Danielle Lapp have spent more than 20 years studying memory and learning in people over age 55. They have found a striking difference between young and old: as people age, they cannot depend on the unconscious, spontaneous processes that made memory seem effortless in their youth. There’s an upside, however. Lapp and Yesavage have also discovered that most people can compensate for this by practicing conscious mental strategies as they get older. Over the years, the Stanford pair has developed a vast range of memory-training exercises. Their regimen demands effort, but Lapp and Yesavage say it can boost memory capacity by about 30 percent—the amount a person typically loses between 20 and 70 years of age.
The two researchers work together, but in very different roles. “I’m like the producer and she’s the actor,” Yesavage says. Lapp teaches all the experimental classes, devises training techniques and helps design the study protocols. She has written three popular books on improving memory skills. Yesavage, who carries major administrative responsibilities at the Palo Alto VA Medical Center, brings in the research grants and analyzes the research data.
They also differ in personal style, which may be one reason they make such an effective team. Lapp is the quintessential humanist, an elegant Frenchwoman who has a pleasing Gallic obsession with making life more aesthetic. In conversation, she is a wellspring of ideas and illustrative gestures. (Her rallying cry in class is “Make it a game!”) Raised in Paris, she absorbed Proust, Montaigne and Rousseau on her way to studying literature at the universities of Nice, Strasbourg and Paris Sorbonne.
Yesavage is the apotheosis of an American scientist—a tall, energetic man who is friendly but measured and precise. He is more reserved than Lapp, but he lights up when talking about a puzzling psychiatric case or discussing his love of trout. His interest in medicine traces to his boyhood in Kearny, N.J., when he watched his father slowly decline from Parkinson’s disease.
Yesavage began to focus on memory in 1978 after finishing medical school and starting to do research on Alzheimer’s disease. At that time, he noticed that psychology professor Gordon Bower was demonstrating certain powerful methods for helping Stanford undergraduates memorize long lists of words. Yesavage and Bower decided to try the approach with older people.
Yesavage recruited about a dozen people, all over 55 years old, to learn Bower’s techniques and to take memorization tests before and after. In order to carry out the experiment, he needed a skilled instructor who could faithfully teach Bower’s techniques to the study participants. It so happened that Yesavage was brushing up on his French, taking a Stanford course taught by a dynamic and lovely instructor—Danielle Lapp. He first asked her to help him by becoming the teacher in his study, and much later began to ask her out.
Although the relationship succeeded, the initial study failed miserably. Yesavage and Lapp spent the next two decades trying to find out why.
Around the same time, other scientists were piecing together a broad understanding of how memory works. Those findings created a context for the Stanford results, revealing a landscape of “normal” memory that was often as strange as a Dali painting.
Scientists already knew there were two kinds of memory: short-term and long-term. Short-term, or “working,” memory allows us to retain facts—like phone numbers and names—for about five seconds, giving the conscious mind time to use them before tossing them out. If we “work” these memories again and again, they move into long-term storage.
In the last two decades, researchers have discovered the processes underlying long-term memory. They have found that we store our perceptions as patterns of neurochemical changes that allow us to retrieve them hours, days or years down the road. We now know that when we look at an orange, for instance, the brain splits the overall visual image into nerve impulses that signal the color, the shape, the texture and so on. Each of these sensory elements is compared with memories of similar elements, stored in completely different parts of the brain that specialize in shape, color or texture.
When the brain weaves the sensory threads together, they form a pattern of sensations that can be compared with previous, similar patterns. The brain next completes the pattern of sensations, filling in the blanks. “Ah,” the brain says, “orange-colored sphere with dimpled skin, fits in the palm—I’ve encountered it before. That means it’s also edible, a fruit, sweet, fragrant.” The brain then reinforces the whole pattern for subsequent reference.
Scientists who study memory used to wonder if there were such a thing as a “grandmother neuron,” a single nerve cell that would light up when someone thought of a grandmother. Now they know that there is not, just as there is no single “orange neuron.” There is merely a large number of neural clusters throughout the brain, each holding the memory of one of the features that grandmothers have. When we think of a grandmother, the neural clusters holding the memories of these elements all activate at the same time, giving us the image of a grandmother.
Because each element of a memory is connected to so many other pieces of the memory, we strengthen our recall by adding in as many sensations as possible. Any part of a memory—a smell, a color, a sound—can be enough to bring back the whole experience. The more threads there are in the memory, the more points there are for accessing the whole pattern.
“That’s something we didn’t understand 20 years ago—the importance of what we call depth of processing in making memories stronger,” Yesavage says.
Other research has clarified the many ways in which memory can fail. As scientists now see it, perception is more a process of throwing things out than of storage. When we go shopping specifically for oranges, our eyes behold many fruits and vegetables in that section of the store. But with the mind focused on the sweet orange fruit that we remember deciding to buy, most of the other produce will go largely unnoticed.
Even the things we do notice can fall through the mind’s sieve without leaving a trace. Or an impression may be relegated to some memory backwater where it is almost impossible to retrieve. We believe we can reconstruct what we remember seeing, but the brain has a way of papering over flaws in our memory, filling the gaps with things that may not be true. Psychologists have found that eyewitnesses to a crime are often inaccurate in their descriptions of what happened. We think of memory as a near-perfect picture—but like a photograph under a magnifying glass, it’s actually quite grainy, and many of the fine details are never recorded at all.
It's impossible, then, to make perfect memories of everything—at any age. But with time, certain processes become even less efficient and some types of memories get even grainier than before. Yesavage and Lapp have delineated some of those changes.
Visual memory diminishes the most with age, the Stanford researchers found. Strong visualization—which comes naturally to the young—“guarantees excellent recall,” says Lapp. When it fades, the loss hits particularly hard. That’s because most of our memories are stored at least partly through visualization, the process of observing something closely and implanting a mental image of it. Visual recall is what enables us to link names with faces or to memorize long lists of words—which helps to explain why older people had such trouble with Bower’s approach.
Concentration also declines with age, making it harder to multitask or to stay focused in the face of distractions. Attention spans get shorter, and we may have some trouble organizing diverse thoughts. Reaction time slows by a few critical seconds, creating embarrassing lags in recall. And the anxiety caused by those lapses (the “tip of the tongue” phenomenon) makes remembering even harder.
Fortunately, some types of memory remain unchanged by age, including what Lapp calls recognition memory. “If you have recorded it in the first place, you usually still recognize a face or place,” she explains in Maximizing Your Memory Power (Barron’s Educational Series, 1998). Another stable process is kinesthetic memory, used for tasks like typing, hitting a backhand or dancing a tango.
And there is one aspect of recall—our verbal memory bank—that actually gets richer with age. Vocabulary range and overall facility with language increase naturally with decades of reinforcement.
This principle also applies to long-practiced skills and informed judgments. “Experience is your strong suit,” Lapp tells her aging students. “Old information, this reservoir of knowledge and experience acquired since birth, remains intact in your memory bank. Your ability to make evaluations, judgments, associations and comparisons will always be there to help you.”
These insights, and scores of inventive coping strategies, come from the dozens of studies Lapp and Yesavage have conducted since that first, failed experiment. Funded with a series of major grants from the National Institute of Mental Health, the continuing project is “one of the most systematic research programs on memory training of older people in the field [of cognitive science],” says Sherry Willis, a leading cognitive researcher based at Penn State.
For each experiment, Yesavage and Lapp recruit up to 300 men and women over age 55 and randomly assign them to one of two so-called “memory-enhancement” classes. One class gets actual memory training, while the control group simply gets tips on “positive aging”—basically, feeling good about growing older. Both groups take memory tests at the beginning of the class, at the end of the class and six months after the class ends.
Lapp and Yesavage have a favorite metaphor to describe their approach to memory training. “I like to compare our memory to a camera that is autofocus when we are younger, but demands that we switch to manual focus as we grow older,” Lapp says. Working to understand the processes of memory, and then learning to operate them “manually,” takes conscious, concerted effort, but the studies show that the payoff can be great.
What we need to do, says Lapp, is to become more selective about the kinds of things we want to remember, and to foster habits that increase our memory of those things. The very first habit—the primary rule of improving memory—is simply to pay attention. This may seem obvious for a person studying for a test or trying to learn a language. But most of us don’t realize how much of our lives we spend running on automatic pilot. “Automatic behavior is a killer,” Lapp says. “When you do something in an absentminded way, the mind is absent.”
She urges people to really take in the action, to build the kind of multisensory links that strengthen memory formation. Think of memory as the fabric made from those threads of previous sensations and memories. If you know you’re going to want to remember where you dropped your keys, or be sure that you locked the car, Lapp suggests pausing during the act and concentrating on what you are doing. Notice the feeling of the keys in your hand. Listen to the keys as they drop on the kitchen counter or turn in the lock. Even unrelated information, like a scent in the air, can reinforce the memory of the keys—if it’s noticed.
Among her many training techniques, Lapp uses art prints to teach people to look at what’s in front of them, to focus their attention and to register what they see. She holds up a postcard of a medieval painting and points out a few things. “A lot of people look at this, see a [typical] Madonna and child, and look away,” she says. “But what I say is to notice her dress, which is voluptuous and red, very unusual for a Virgin Mary. And look at the beautiful curls in her hair, which are more like something you would expect on Mary Magdalene.” As Lapp talks on, she mentions the delicate tracings of the rose vines behind the figures, the expression on the baby Jesus’ face. The portrayal, on close inspection, is anything but generic.
Whether the focal point is a painting, a key or a person’s name, Lapp urges her students to exercise their neural connections by spending more time processing the experience and forging strong sensory and emotional links as they store it as a memory. Most people’s strongest memories have a heavy emotional component, like the JFK assassination, the first lunar landing or a wedding anniversary, but it’s entirely possible to strengthen memory storage in the absence of extreme emotions, Lapp says. Simply noting how you feel at the moment can be enough to make the new memory stick.
To retrieve a memory, Lapp encourages people to let themselves follow the emotional threads that connect memories to each other. “People always talk about Proust and all that he remembers after tasting the madeleine, but look at how he does it: he allows himself to follow along a chain of memories,” Lapp says. “Most people would stop after the first association, but he lets himself get carried along from one memory to another.”
Most graduates of her “real” memory-enhancement classes say they notice a difference, Lapp says. “One student, a curator of an art museum, came and told me she had learned to look at art in a new way,” she recalls. The woman said that she had begun analyzing paintings much more systematically and that working on memory had, in fact, changed the way she saw the world.
Others report more modest gains. Denise Hammerschlag, 74, and her husband, Daniel, have a lifetime of powerful memories, some of which they might wish to forget. They lived in Belgium until the Nazis invaded in 1940, then fled into France and then to Spain one week ahead of the German army. They ended up in Argentina and had a full life there before moving to Mountain View four years ago to be closer to their grown children. That’s when Denise Hammerschlag began to notice some difficulty in recalling new information. She found that some of the simple association techniques Lapp teaches, such as consciously linking Page Mill Road with a book page and a grain mill, helped her remember street directions. “Before, I could never remember that name,” she says. The classes helped her remember people’s names as well.
While those benefits might seem small, Lapp and Yesavage point out that even little improvements can help make life manageable for people who are beginning to have trouble remembering things.
Lately, a different puzzle has drawn the pair’s attention. In study after study, about 20 percent of the participants mysteriously don’t improve, and Yesavage and Lapp want to know why. Do these individuals simply lack the motivation to perform the difficult work of changing the way they think? “When people get older, they sometimes decide that all of these techniques are too strange and difficult,” Lapp says. Or do they suffer from depression, which interferes with memory and is common among the elderly? Or might some have an early, undetected form of Alzheimer’s disease, which would prevent psychological techniques alone from improving memory skills?
To find out more, Yesavage and Lapp are recruiting volunteers for a major new study. Funded with a sizable grant from the National Institute of Mental Health, the experiment will compare two groups: one receiving the memory training plus a placebo pill, the other receiving the training while taking a recently developed drug that has been shown to safely promote memory in Alzheimer’s patients. The drug slightly increases the activity of the neurotransmitter acetylcholine, which the brain uses during memory formation.
The combined behavioral-drug approach is “truly cutting-edge,” says Willis. “To my knowledge, there are few, if any, other studies of this type.”
After all these years of peering at memory, Lapp and Yesavage say they have learned to be more respectful of its power and more tolerant of its inherent graininess. “I’ve come to see it as a miracle how much we do remember,” Lapp says.
The whole concept of memory does seem to have a metaphysical side. People often think of memory as belonging to the past, and perception as belonging to the present, but the distinction is not really all that clear. After all, memories are by definition recollections of the past. But when does the past begin? Years ago? Yesterday? A fraction of a moment ago? On some level, all thought and emotion is remembering; and consciousness itself is what Nobel laureate Gerald Edelman calls a “remembered present.”
So someone, somewhere might be trying to remember the act of locking his car door in a parking lot one summer evening when his ear records the click of the key and his eye catches the glint of a low-slanting sun. And the air carries a scent of cooling asphalt, and honeysuckle, and eucalyptus, and a certain breeze or something makes him stop for a moment and think about being alive, and maybe about boisterous evenings long ago plotting political strategy among the haystacks behind the eating clubs. At that moment, the past is brought to life and the present is transformed. At that moment, memory is as much about relishing the present as it is about treasuring the past.
Christopher Vaughan is a science writer living in Menlo Park.