It's a Jungle in There: How Competition and Cooperation in the Brain Shape the Mind (25 page)

Coordination = Competition + Cooperation

The right-hand side of the equation maps onto the subtitle of this book,
How Competition and Cooperation in the Brain Shape the Mind
. This is hardly coincidental, in my opinion. Much as von Holst saw fit to summarize all that he knew about perception and action by referring to the combination of competition and cooperation, I see fit to say that these two forces are the ultimate mediators of
all
experience. Shaped by evolutionary pressures, not just over the eons of evolution but also over the span of individual lives, competition and cooperation within the brain shape the way we act. It could not be otherwise, in my view, since the control of action is one of the most basic functions of the nervous system.

When I turn to the topic of learning and memory in the class where I first said, “It’s a jungle in there,” I show a cartoon from
The New Yorker
featuring “Mr. Total Recall,” a fictional character who seems to remember everything. In the cartoon, this figure recollects every bit of a long-past meeting with the other character in the cartoon, a puzzled-looking man who clearly is unable to remember the perfect-memory freak. The man with imperfect memory is like the rest of us. He remembers some things but not others. What he remembers matters to him. What’s unimportant to him has vanished from his mind, if it ever entered.
¹

Though perfect recall is a joke, many people crave it, spending fistfuls of dollars on memory-improvement books and other aids to help them remember names of people they’ve met, facts they think they’ll need for exams, and so on. Forgetting someone’s name can be bad for business, just as forgetting facts for exams can be bad for GPAs. In the outer jungle, forgetting what a sickening mushroom looks like can be deadly, as can forgetting that a patch of ground was quicksand.
²

While it helps to remember things in some circumstances, in others forgetting can be a boon, not a bane. If you were raped—of course I hope you weren’t, though the statistics concerning sexual abuse are all too high—you may wish you could forget that terrible event. If you were a soldier who saw a buddy blown up in battle, that horrific image may stay with you no matter how hard you try to forget it. Ironically, the more you try to forget awful experiences, the harder it is to do so. Trying to forget something specific can, ironically, increase the odds of remembering it.
³

Examples like these suggest some of the questions a theory of learning and memory should answer: Why do we remember some things but not others? What happens when we forget? When we do forget, does information vanish entirely, or does it just become hard to find? When we remember something but don’t remember it exactly, is that a worrying sign of impending senility or
just a result of normal processes? When we try to forget something but can’t, why can’t we?

Forgetting much more than you want can, of course, be a cause for concern. On the other hand, occasional lapses of memory are just what you’d expect if you thought learning and remembering reflect internal competition and cooperation among neural agents. Accordingly, I’ll argue that memory representations generally get strong when they develop friendly associations, or they get weak otherwise. Saying this another way, the chance that a memory survives depends on how well it fits its environment: The better the fit, the better its fate.
⁴

Consider a librarian who does her best to keep all the books in her library where they belong. Despite her best efforts, some books get misplaced. Absentminded readers move volumes to errant locales. Mischievous visitors hide books in secret spots. When a book can’t be located, the problem isn’t that the book has left the library. It’s that it has become buried somewhere and is hard to find.

A challenge in studying learning and memory is to determine whether forgetting is due to loss of information or to difficulty of retrieval. Like a misplaced library book, a memory may be “somewhere in your brain” but hard to locate. The challenge for all of us going about our lives is to retrieve what we want to, though some of it may be hard to find. The further challenge for memory researchers is to find out whether memories that seem to be gone forever are merely elusive.

Showing that forgotten material actually exists is a little like searching for life on other planets. Not finding it doesn’t prove it’s not there. Little green men or women could be wandering around their extraterrestrial worlds. Not spotting them doesn’t prove they don’t exist. They could be sailing their Saturnian seas or roving their Jovian jungles. They could be remembering where safe mushrooms can be found and where quicksand pits can be avoided. If they remember where strong vines can be grasped for swinging, that knowledge can help them survive. Learning the ropes, by this fanciful example, is truly a universal concern. But more to the point, not finding something doesn’t prove it doesn’t exist.

If you don’t remember something, it could be that a little librarian in your head has a hard time finding what she’s looking for. That proposal sounds
outlandish, but to some degree you may subscribe to it when you say things like, “I’m searching my memory,” or “I’m trying to remember.” When you say such things, it’s as if you’re claiming that you’re rushing around in your own head, scanning mental shelves for something you think is present. This claim is fraught with problems, of course.
You
can’t be inside
your
own head!

How can you make headway on this problem? Consider what determines whether memories can be found. Presumably, memories can be located if they’re strong, which they are if they’re powerfully activated. Memories are activated when relevant cues come along, and the activation is powerful when it doesn’t take much cuing for the memories to sally forth. Having many reliable friends can help memories achieve this status. Having few adversaries can help as well.

To make more sense of how this works, consider some methods that have been used to bring memories to the fore. One is electrical stimulation of the brain. This method has been used in neurosurgery. It was pursued most famously by the Canadian neurosurgeon, Wilder Penfield, whose medical achievements became so influential that a boulevard was named for him in Montreal, the city where he practiced.
⁵

Penfield treated epileptic patients for whom drugs were ineffective. To help his patients, Penfield performed brain surgery on them, attempting to deactivate the sources of the seizures or at least to retard their spread. Penfield wanted to make sure he didn’t cut nerve tracts that were crucial for basic functions like moving or talking, so he used electrodes to record from brain sites in the patients. The other technique he used was to stimulate those sites to determine what roles they played. His patients volunteered for the procedure, were awake while it was performed, and felt no pain from the brain treatment itself.
⁶

Penfield found that electrical stimulation of the brain elicited long-lost memories. Patients who had not thought of events for years reported re-experiencing those events when their brains were stimulated. Based on the apparent release of seemingly lost memories, Penfield suggested that more information is stored in the brain than is evident from ordinary recall. He even hypothesized that everything we experience is retained.
⁷

Hypothesizing that nothing is forgotten is a strong claim, of course. It may be too strong, for if
some
memories can be activated by electrifying the brain, it doesn’t follow that
all
memories can be reignited.
⁸
Nevertheless, the hypothesis is intriguing. Penfield was surely correct in suggesting that more is available in memory than might be imagined at first.

Trying to revive long-lost memories through electrical stimulation of the brain isn’t the most practical means of reawakening memories in everyday life. Another way is to rely on recognition rather than recall. In recognition, you indicate whether you’ve encountered something before. In recall, you reveal what you remember by recounting your experience, typically by describing what you saw or heard.

Recognition is generally easier than recall. A famous demonstration of this truism was provided in a study of memory for former high-school classmates.
⁹
Healthy people of various ages were asked to recall the names of people with whom they went to high school. In another condition, they were asked to recognize faces in yearbooks. Some yearbooks were from the participants’ own high schools. Other yearbooks were from other high schools whose student populations had similar demographics.

The older the participants, the worse their recall, a result that is understandable from the standpoint that older people may have poorer recall abilities than younger people. Alternatively, it could be that older people had to go farther back in time than the younger ones. Young people don’t have classmates from 50 years ago. Senior citizens do. Older folks also have more stuff to remember. An 80-year-old has roughly 4 times as much experience as a 20-year-old, assuming experiences—however they might be defined—come at a roughly constant rate.

The most striking result of the study was that, no matter how old the participants their recognition remained steady and very high (close to 90%), even 50 years hence. So people who had graduated from high school half a century before could recognize pictures of their classmates, even though they could not recall those people when asked simply to say who their classmates were.

This remarkable finding shows that recognition can be extremely durable though recall may slip. Another lesson from this study is that basing appraisals of memory on free recall can lead to underestimates of how much is stored. Relying on recognition shows that more is there than might at first be apparent.

Why is recognition generally easier than recall? To pursue this question, imagine an elderly lady looking at a picture of a teenage boy in a yearbook
photo. The boy is dressed and coiffed as teenage boys were back in her day. The senior-citizen subject has a vague feeling she recognizes the boy, but she’s not sure. Then she’s given a cue. “School orchestra,” the experimenter whispers. Suddenly she recognizes the youth. He played the trumpet in the high school orchestra. She played the French horn. The verbal cue boosts her memory enough to move her from a vague feeling of knowing to a surety of knowing. Now she recognizes the boy and recalls something about him. He once arrived late to a rehearsal and the teacher scolded him. What was the boy’s name again? She can’t quite remember, but other facts come back to her in a flood—what the room looked like, what it felt like to hold her French horn, and the memory that her friend Bea told her she thought the boy was cute.

What all this shows—though the anecdote is fictional—is that memories have aspects. For the lady looking at the yearbook, some of those aspects were activated by sight of the boy. When an extra cue was given to her (“school orchestra”), other aspects were activated. The result of the refresher was more vivid recollection.
¹⁰

Here’s another demonstration of the way cuing can help. The demonstration concerns bringing people from a state of not being able to recall to a state of being able to recall. I use the demonstration in my cognitive psychology class. First, I read aloud a list of words, and then I ask the students to recall as many words as possible. Here’s a typical list:

yacht, canoe, raft

celery, carrot, cucumber

skunk, raccoon, squirrel

Pabst, Sam Adams, Budweiser

salmon, trout, flounder

Poland, Germany, France

psychiatrist, dermatologist, cardiologist

plum, peach, grapefruit

Colorado, Idaho, Wyoming

elbow, shoulder, neck

Of the thirty items in the list, the students typically recall half of them. After the students have written down as many words as they can, I call out a cue word and ask the students to write down any additional words they can think of. If I say “fish”—the category name for a triplet on the list (“salmon, trout, flounder”)—a few students write down those words if they omitted them. If I say “beer”—the category name for another triplet on the list (“Pabst,
Sam Adams, Budweiser”)—some students write down beer terms they may have left out. Apparently, with a little help from their friends, memory items can be “brought to the surface.”

Notice that the cues that helped in the demonstration were words that conveyed the meaning of a
set
of words in the list. Even though the word “fish” was not in the list, three of the words were “fishy enough” that the “fish” cue triggered recall of the fish words. From this you can infer that memory demons whose niches included the fish concept were turned on by other memory demons whose niches included particular fishes. Once the fish cue activated those demons, it became possible to recall the relevant terms.

Cues that enable recall needn’t be names of semantic categories. They can be words that sound like words to be remembered, tunes associated with words to be recalled, strokes on the cheek that relate to words to be remembered, olfactory stimuli (smells), and so on.

Smells, it turns out, are especially evocative, perhaps owing to their ties to primordial needs like eating, drinking, and nuzzling up to mommy. A famous account of odor-based cuing came from the nineteenth-century French author, Marcel Proust, whose novel,
À la recherche du temps perdu (In Search of Lost Time
), which he wrote between 1909 and 1922, described the awakening of childhood memories by the smell of a cake. In the incident, the adult character in the novel smells something he hasn’t smelled since childhood—a cake baked by his aunt when he was a little boy. The smell of the cake—
le petit madeleine
—released memories pent up in his mind. Suddenly, upon smelling le petit madeleine, he remembers experiences that, ostensibly, had been lost forever.