How We Learn (26 page)

The study had the feel of a card trick. After displaying the “target” doodle for five seconds, the experimenters slipped it into a deck of thirty-four similar flashcards. “Some of the items in the pack are exact replicas, tell me which ones,” they said, and then began showing each card, one at a time, for three seconds. In fact, the deck contained four exact replicas, and thirty near-replicas:

The skill the Gibsons were measuring is the same one we use to learn a new alphabet, at any age, whether Chinese characters, chemistry shorthand, or music notation. To read even a simple melody, you have to be able to distinguish an A from a B-flat on the clef. Mandarin is chicken scratch until you can discriminate between hundreds of similar figures. We’ve all made these distinctions expertly, most obviously when learning letters in our native tongue as young children. After that happens and we begin reading words and sentences—after we began “chunking,” in the same way the chess masters do—we forget how hard it was to learn all those letters in the first place, never mind linking them to their corresponding sounds and blending them together into words and ideas.

In their doodle experiment, the Gibsons gave the participants no feedback, no “you-got-its” or “try-agains.” They were interested purely in whether the eye was learning. And so it was. The adults in the experiment needed about three times through, on average, to score perfectly, identifying all four of the exact replicas without making
a single error. The older children, between nine and eleven years old, needed five (to get close to perfect); the younger ones, between six and eight years old, needed seven. These people weren’t making S-R associations, in the way that psychologists assumed that most learning happened. Nor were their brains—as the English philosopher John Locke famously argued in the seventeenth century—empty vessels, passively accumulating sensations. No, their brains came equipped with evolved modules to make important, subtle discriminations, and to put those differing symbols into categories.

“Let us consider the possibility of rejecting Locke’s assumption altogether,” the Gibsons wrote. “Perhaps all knowledge comes through the senses in an even simpler way than John Locke was able to conceive—by way of variations, shadings, and
subtleties of energy.”

That is, the brain doesn’t solely learn to perceive by picking up on tiny differences in what it sees, hears, smells, or feels. In this experiment and a series of subsequent ones—with mice, cats, children, and adults—Gibson showed that it also
perceives to learn
. It takes the differences it has detected between similar-looking notes or letters or figures, and uses those to help decipher new, previously unseen material. Once you’ve got middle-C nailed on the treble clef, you use it as a benchmark for nearby notes; when you nail the A an octave higher, you use that to read its neighbors; and so on. This “discrimination learning” builds on itself, the brain hoarding the benchmarks and signatures it eventually uses to read larger and larger chunks of information.

In 1969, Eleanor Gibson published
Principles of Perceptual Learning and Development
, a book that brought together all her work and established a new branch of psychology: perceptual learning. Perceptual learning, she wrote, “is not a passive absorption, but an active process, in the sense that exploring and searching for perception itself is active. We do not just see, we look; we do not just hear, we listen. Perceptual learning is self-regulated, in the sense that modification
occurs without the necessity of external reinforcement. It is stimulus oriented, with the goal of extracting and reducing the information simulation. Discovery of distinctive features and structure in the world is fundamental in the
achievement of this goal.”

This quote is so packed with information that we need to stop and read closely to catch it all.

Perceptual learning is active. Our eyes (or ears, or other senses) are searching for the right clues. Automatically, no external reinforcement or help required. We have to pay attention, of course, but we don’t need to turn it on or tune it in. It’s self-correcting—it tunes itself. The system works to find the most critical perceptual signatures and filter out the rest. Baseball players see only the flares of motion that are relevant to judging a pitch’s trajectory—nothing else. The masters in Chase and Simon’s chess study considered fewer moves than the novices, because they’d developed such a good eye that it instantly pared down their choices, making it easier to find the most effective parry. And these are just visual examples. Gibson’s conception of perceptual learning applied to
all
the senses, hearing, smell, taste, and feel, as well as vision.

Only in the past decade or so have scientists begun to exploit Gibson’s findings—for the benefit of the rest of us.

• • •

The flying conditions above Martha’s Vineyard can change on a dime. Even when clouds are sparse, a haze often settles over the island that, after nightfall, can disorient an inexperienced pilot. That’s apparently what happened just after 9:40
P.M.
on July 16, 1999, when John Kennedy Jr. crashed his Piper Saratoga into the ocean seven miles offshore, killing himself, his wife, and her sister. “There was no horizon and no light,” said another pilot who’d flown over the island that night. “I turned left toward the Vineyard to see if it was visible but could see no lights of any kind nor any evidence of the island. I
thought the island might have suffered a power failure.” The official investigation into the crash found that Kennedy had fifty-five hours of experience flying at night, and that he didn’t have an instrument rating at all. In pilot’s language, that means he was still learning and not yet certified to fly in zero visibility, using only the plane’s
instrument panel as a guide.

The instruments on small aircraft traditionally include six main dials. One tracks altitude, another speed through the air. A third, the directional gyro, is like a compass; a fourth measures vertical speed (climb or descent). Two others depict a miniature airplane and show banking of the plane and its turning rate
through space, respectively (newer models have five, no banking dial).

Learning to read any one of them is easy, even if you’ve never seen an instrument panel before. It’s harder, however, to read them all in one sweep and to make the right call on what they mean collectively. Are you descending? Are you level? This is tricky for amateur pilots to do on a clear day, never mind in zero visibility. Add in communicating with the tower via radio, reading aviation charts, checking fuel levels, preparing landing gear, and other vital tasks—it’s a multitasking adventure you don’t want to have, not without a lot of training.

This point was not lost on Philip Kellman, a cognitive scientist at Bryn Mawr College, when he was learning to fly in the 1980s. As he moved through his training, studying for aviation tests—practicing on instrument simulators, logging air time with instructors—it struck him that flying was mostly about perception and action. Reflexes. Once in the air, his instructors could see patterns that he could not. “Coming in for landing, an instructor may say to the student, ‘You’re too high!’ ” Kellman, who’s now at UCLA, told me. “The instructor is actually seeing an angle between the aircraft and the intended landing point, which is formed by the flight path and the ground. The student can’t see this at all. In many perceptual situations like
this one, the novice is essentially blind to patterns that the expert has come to see at a glance.”

That glance took into account
all
of the instruments at once, as well as the view out the windshield. To hone that ability, it took hundreds of hours of flying time, and Kellman saw that the skill was not as straightforward as it seemed on the ground. Sometimes a dial would stick, or swing back and forth, creating a confusing picture. Were you level, as one dial indicated, or in a banking turn, like another suggested? Here’s how Kellman describes the experience of learning to read all this data at once with an instructor: “While flying in the clouds, the trainee in the left seat struggles as each gauge seems to have a mind of its own. One by one, he laboriously fixates on each one. After a few seconds on one gauge, he comprehends how it has strayed and corrects, perhaps with a jerk guaranteed to set up the next fluctuation. Yawning, the instructor in the right seat looks over at the panel and sees at a glance that the student has wandered off of the assigned altitude by two hundred feet but at least has not yet turned the plane upside down.”

Kellman is an expert in visual perception. This was his territory. He began to wonder if there was a quicker way for students to at least get a feel for the instrument panel before trying to do everything at once at a thousand feet. If you developed a gut instinct for the panel, then the experience in the air might not be so stressful. You’d know what the instruments were saying and could concentrate on other things, like communicating with the tower. The training shortcut Kellman developed is what he calls a perceptual learning module,
or PLM. It’s a computer program that gives instrument panel lessons—a videogame, basically, but with a specific purpose. The student sees a display of the six dials and has to decide quickly what those dials are saying collectively. There are seven choices: “Straight & Level,” “Straight Climb,” “Descending Turn,” “Level Turn,” “Climbing Turn,” “Straight Descent,” and the worrisome “Instrument Conflict,” when one dial is stuck.

In a 1994 test run of the module, he and Mary K. Kaiser of the NASA Ames Research Center brought in ten beginners with zero training and four pilots with flying experience ranging from 500 to 2,500 hours. Each participant received a brief introduction to the instruments, and then the training began: nine sessions, twenty-four presentations on the same module, with short breaks in between. The participants saw, on the screen, an instrument panel, below which were the seven choices. If the participant chose the wrong answer—which novices tend to do at the beginning—the screen burped and provided the right one. The correct answer elicited a chime. Then the next screen popped up: another set of dials, with the same set of seven choices.

After one hour, even the experienced pilots had improved, becoming faster and more accurate in their reading. The novices’ scores took off: After one hour, they could read the panels as well as pilots with an average of one thousand flying hours. They’d built the same reading skill, at least on ground, in 1/1,000th of the time. Kellman and Kaiser performed a similar experiment with a module designed to improve visual navigation using aviation charts—and achieved
similar results. “A striking outcome of both PLMs is that naïve subjects after training performed as accurately and reliably
faster
than pilots before training,” they wrote. “The large improvements attained after modest amounts of training in these aviation PLMs suggest that the approach has promise for accelerating the acquisition of skills in aviation and
other training contexts.”

Those contexts include any field of study or expertise that involves making distinctions. Is that a rhombus or a trapezoid? An oak tree or a maple? The Chinese symbol for “family” or “house”? A positive sloping line or a negative sloping one? Computer PLMs as Kellman and others have designed them are visual, fast-paced, and focused on classifying images (do the elevated bumps in that rash show shingles, eczema, or psoriasis?) or problems rather than solving them outright (does that graph match x—3y = 8, or x + 12 y + 32?). The modules are intended to sharpen snap judgments—perceptual skills—so that you “know” what you’re looking at without having to explain why, at least not right away.

In effect, the PLMs build perceptual intuition—when they work. And they have, mostly, in several recent studies. In one, at the University of Virginia, researchers used a perceptual learning module to train medical students studying gallbladder removal. For most of the twentieth century, doctors had removed gallbladders by making a long cut in the abdomen and performing open surgery. But since the 1980s many doctors have been doing the surgery with a laparoscope, a slender tube that can be threaded into the abdominal cavity through a small incision. The scope is equipped with a tiny camera, and the surgeon must navigate through the cavity based on the images the scope transmits. All sorts of injuries can occur if the doctor misreads those images, and it usually takes hundreds of observed surgeries to master the skill. In the experiment, half the students practiced on a computer module that showed short videos from real surgeries and had to decide quickly which stage of the surgery was pictured. The other half—the control group—studied the same videos
as they pleased, rewinding if they wanted. The practice session lasted about thirty minutes. On a final test, the perceptual learning group trounced their equally experienced peers, scoring
four times higher.