A big idea—if true.
It might have been a fluke, given the strangeness of the task: blind beanbag tossing. Not that it mattered at the time, in part because no one was paying attention. The beanbag experiment was as obscure as they come. (So much so that it disappeared entirely from the website of the journal in which it originally appeared, Perceptual and Motor Skills; it took editors weeks to find it when I asked.) Yet even if the study had made the nightly news, it’s not likely to have changed many minds, certainly not among the academics studying memory. Kinetics and cognitive psychology are worlds apart in culture and in status. One is closer to brain science, the other to gym class. A beanbag study with a bunch of eight-year-olds and twelve-year-olds wasn’t about to alter centuries of assumptions about how the brain acquires new skills. At least not right away.
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Psychologists who study learning tend to fall into one of two camps: the motor/movement, or the verbal/academic. The former focuses on how the brain sees, hears, feels, develops reflexes, and acquires more advanced physical abilities, like playing sports or an instrument. The latter investigates conceptual learning of various kinds: language, abstract ideas, and problem solving. Each camp has its own vocabulary, its own experimental paradigms, its own set of theories. In college, they are often taught separately, in different courses: “Motor and Perceptual Skills” and “Cognition and Memory.”
This distinction is not an arbitrary one. Before we go any further, let’s revisit, briefly, the story of Henry Molaison, the Hartford man whose 1953 surgery for epilepsy severely damaged his ability to form new memories. After the surgery, Molaison’s brain could not hold on to any describable memories, such as names, faces, facts, and personal experiences. The surgeon had removed the hippocampus from both hemispheres of his brain; without those, Molaison could not move short-term memories into long-term storage. He could, however, form new motor memories. In one of the experiments described in chapter 1, Molaison learned to trace a star while watching his drawing hand in a mirror. He became more and more adept at this skill over time, even though he had no memory of ever practicing it.
A major implication of the Molaison studies was that the brain must have at least two biological systems for handling memory. One, for declarative memories, is dependent on a functioning hippocampus. The other, for motor memories, is based in different brain organs; no hippocampus required. The two systems are biologically distinct, so it stood to reason that they’re functionally distinct, too, in how they develop, strengthen, and fade. Picking up Spanish is not the same as picking up Spanish guitar, and so psychology has a separate tradition to characterize each.
In the early 1990s, a pair of colleagues at UCLA decided to try something radical: They would combine the two traditions—motor and verbal—into a single graduate seminar, which they called “Principles of Motor and Verbal Learning.” The two researchers—Richard A. Schmidt, a motor-learning specialist, and the ever-present Robert Bjork, a verbal-learning expert—thought students would gain a better understanding of the main distinctions between their respective fields and how each type of learning is best taught. “Dick and I just assumed we’d lay out what the differences were between motor and verbal, nothing more than that,” Bjork told me. “But as we got deeper into it, the whole project changed course.”
An odd signal echoed down through the literature, they saw. For starters, they stumbled upon the neglected beanbag study, and took its conclusions at face value, as valid. They then searched the literature to see if they could find other studies in which mixed or interrupted practice sessions led to better performance over time than focused ones. If the beanbag result was solid, and Kerr and Booth were correct in arguing that it revealed a general principle of learning, then it should show up in other experiments comparing different practice techniques.
And so it did, in papers by researchers who weren’t familiar with Kerr and Booth’s work at all. In 1986, for instance, researchers at Louisiana State University tested how well thirty young women learned three common badminton serves. The short serve, the long, and the drive each has a distinct trajectory and takes some practice to hit well. To make a short serve, the player has to hit the shuttlecock just over the net (no more than fifty centimeters, or a foot and a half) so that it lands in the front third of the opposing court. A long serve passes at least two and half meters (about eight feet) above the net and lands in the back third of the opposite court. A drive splits the difference and darts downward to the midline on the other side. The researchers—Sinah Goode and Richard Magill—judged the serves by two criteria: where they landed and where they passed over the net. They split the women into three groups of ten, each of which practiced according to the same schedule, for three days a week over three weeks, thirty-six serves at a time. The sessions themselves were different, however. Group A performed blocked practice, rehearsing only one type of serve per session: doing thirty-six short ones on one day, for instance, thirty-six long ones the next session, and thirty-six drives the next. Group B performed serial practice, trying the serves in a given order—short, then long, then drive—repeatedly. Group C practiced randomly, trying any serve they wanted but no more than two of the same ones in a row.
By the end of the three weeks, each participant had practiced each serve the same number of times, give or take a few for those in the random group.
Goode and Magill wanted not only to compare the relative effectiveness of each type of practice schedule. They also wanted to measure how well the participants’ skills transferred to a new condition. Transfer is what learning is all about, really. It’s the ability to extract the essence of a skill or a formula or word problem and apply it in another context, to another problem that may not look the same, at least superficially. If you’ve truly mastered a skill, you “carry it with you,” so to speak. Goode and Magill measured transfer in a subtle, clever way. On their final test of skill, they made one small adjustment: The participants served from the left side of the court, even though they’d practiced only on the right. During the test, the examiner called out one skill after another: “Hit me a drive … Okay, now a short serve … Now give me a long one.” Each participant hit each serve the same number of times on the final test—six—though never two of the same kind in a row. Goode and Magill then rated each serve, according to its arc and placement, on a scale from 0 to 24.
The winner? Team Random, by a long shot. It scored an average of 18, followed by the serial group, at 14. The blocked practicers, who’d focused on one serve at a time, did the worst, with an average of 12—and this despite having appeared, for most of the three weeks, to be improving the most. They were leading the pack going into Week 3, but come game time, they collapsed.
The authors weren’t entirely sure what caused such a dramatic reversal. Yet they had a hunch. Interfering with concentrated or repetitive practice forces people to make continual adjustments, they reasoned, building a general dexterity that, in turn, sharpens each specific skill. Which, by the way, is exactly what the beanbag study concluded. But Goode and Magill then took it one step further. All that adjusting during a mixed-practice session, they wrote, also enhances transfer. Not only is each skill sharper; it’s performed well regardless of context, whether indoors or out, from the right side of the court or the left. “The general goal of practice is to transfer to a game,” the pair concluded. “A game situation varies from event to event, making random testing the best condition to appraise the effectiveness of practice.”
Schmidt and Bjork knew that this experiment, like the beanbag toss, proved nothing on its own; it was just one study. But there was a scattering of still others—of keyboard ability, of videogame skills, of precise arm movements—and they all had one thing in common: Whenever researchers scrambled practice sessions, in one form or another, people improved more over time than if their practice was focused and uninterrupted.
One way to think about this is in terms of practice versus performance. Duri
ng practice we have a measure of control. We can block out or avoid distractions, we can slow down if needed, and most important, we decide which skill or move or formula we want to rehearse before actually doing it. We’re in charge. Performance is another story. Growing up, all of us knew kids who were exceptional in practice but only mediocre come game time. And vice versa, kids who looked awkward in drills and then came alive when it mattered, during competition, or performing in front of an audience. You can practice the step-over soccer move a thousand times in your front yard, but doing it at full speed with two opposing players running at you is much harder. It’s no longer a single move anymore, practiced in isolation, but one step in an ever-changing, fast-paced dance.
The incorporation of these random demands is what made Kerr and Booth’s observation plausible, and Schmidt and Bjork knew well enough that the principle wasn’t only applicable to physical skills. Digging out verbal memories on a dime requires a mental—if not physical—suppleness that doesn’t develop in repetitive practice as fast as it could. In one previous experiment, Bjork and T. K. Landauer of Bell Laboratories had students try to memorize a list of fifty names. Some of the names were presented for study and then tested several times in succession; other names were presented once and tested—but the test came after the study session was interrupted (the students were given other items to study during the interruption). In other words, each student studied one set of names in an unperturbed session and the other set in an interrupted one. Yet thirty minutes later, on subsequent tests, they recalled about 10 percent more of the names they’d studied on the interrupted schedule. Focused, un-harried practice held them back.
“It has generally been understood that any variation in practice that makes the information more immediate, more accurate, more frequent, or more useful will contribute to learning,” Schmidt and Bjork wrote. “Recent evidence, however, suggests that this generalization must be qualified.”
“Qualified” was a polite way to say “reconsidered” and possibly abandoned altogether.
It’s not that repetitive practice is bad. We all need a certain amount of it to become familiar with any new skill or material. But repetition creates a powerful illusion. Skills improve quickly and then plateau. By contrast, varied practice produces a slower apparent rate of improvement in each single practice session but a greater accumulation of skill and learning over time. In the long term, repeated practice on one skill slows us down.
Psychologists had been familiar with many of these findings, as isolated results, for years. But it was Schmidt and Bjork’s paper, “New Conceptualizations of Practice,” published in 1992, that arranged this constellation of disparate pieces into a general principle that can be applied to all practice—motor and verbal, academic as well as athletic. Their joint class turned out not to be devoted to contrasts, after all, but to identifying key similarities. “We are struck by the common features that underlie these counterintuitive phenomena in such a wide range of skill-learning situations,” they concluded. “At the most superficial level, it appears that systematically altering practice so as to encourage additional, or at least different, information processing activities can degrade performance during practice, but can at the same time have the effect of generating greater performance capabilities.”
Which activities are those? We’ve already discussed one example, in chapter 4: the spacing effect. Breaking up study time is a form of interference, and it deepens learning without the learner investing more overall time or effort. Another example, explored in chapter 3, is context change. Mixing up study locations, taking the books outside or to a coffee shop, boosts retention. Each of these techniques scrambles focused practice, also causing some degree of forgetting between sessions. In their Forget to Learn theory, Robert and Elizabeth Bjork called any technique that causes forgetting a “desirable difficulty,” in that it forces the brain to work harder to dig up a memory or skill—and that added work intensifies subsequent retrieval and storage strength (learning).
But there’s another technique, and it goes right back to the long-lost beanbag study. Remember, the kids who did best on the final test hadn’t practiced on the three-foot target at all. They weren’t continually aiming at the same target, like their peers, doing a hundred A-minor scales in a row. Nor were they spacing their practice, or changing rooms, or being interrupted by some psychologist in a lab coat. They were simply alternating targets. It was a small variation, only a couple of feet, but that alteration represents a large idea, and one that has become the focus of intense study at all levels of education.
• • •
Let’s leave the beanbags and badminton behind for now and talk about something that’s more likely to impress friends, strangers, and potential mates: art. I’m not talking about creating art, I’m talking about appreciating it. One of the first steps in passing oneself off as an urbane figure (so I’m told) is having some idea who actually created the painting you’re staring at. Remarking on Manet’s use of light while standing in front of a Matisse can blow your cover quickly—and force a stinging retreat to the information desk for some instructional headphones.
Yet learning to identify an artist’s individual touch, especially one who has experimented across genres and is not among history’s celebrities, a van Gogh or a Picasso or an O’Keeffe, is not so easy. The challenge is to somehow feel the presence of the artist in the painting, and there’s no simple recipe for doing so. What’s the difference between a Vermeer, a de Heem, and a van Everdingen, for example? I couldn’t pick any one of these Dutch masters out of a lineup, never mind identify the creative signatures that separate one from the others. “The different subjects chosen by Vermeer and de Heem and van der Heyden and van Everdingen are at once different ways of depicting life in 17th-Century Holland and different ways of expressing its domestic quality,” wrote the American philosopher Nelson Goodman in one of his essays on artistic style. “Sometimes features of what is exemplified, such as color organizations, are ways of exemplifying other features, such as spatial patterns.”
Got all that? Me neither.
Goodman famously argued that the more elusive and cryptic an artist’s style, the more rewarding it was for the viewer: “An obvious style, easily identified by some superficial quirk, is properly decried as a mere mannerism. A complex and subtle style, like a trenchant metaphor, resists reduction to a literal formula.” And there’s the rub. Art appreciation is a world removed from biology, playing music, German 101, and the epic poets. There are no word pairs or chemical bonds to study, no arpeggios or verses or other basic facts, no obvious verbal or motor “tasks” to measure. The ability contains an element of witchcraft, frankly, and learning scientists had traditionally left the study of artistic styles to the likes of academics like Goodman.
That all changed in 2006, when Robert Bjork and postdoctoral student Nate Kornell, now at Williams College, decided to test whether a form of interrupted study affected aesthetic judgment in addition to retention. The idea came from a story that one of Bjork’s colleagues had told him, about taking a trip to Italy with her teenage daughter. She—the mother—was excited by the opportunity to visit great museums, such as the Uffizi and Accademia in Florence, the National and Borghese in Rome, as well as the vast Vatican collection, but she worried that the experience would be lost on her daughter, if not actively resisted. She told Bjork that she knew her daughter would get so much more out of the trip if she learned to identify Italian painters’ styles—and had devised a flashcard game that taught her to do just that.
Kornell and Bjork did essentially the same thing in their experiment. They chose a collection of paintings by twelve landscape artists, some of them familiar (Braque, Seurat), but most by artists unfamiliar to the participants, like Marilyn Mylrea, YeiMei, and Henri-Edmond Cross. They then had a group of seventy-two undergraduates study the paintings on a computer screen. Half of the students studied the artists one at a time. For example: They saw one Cross after anoth
er for three seconds each, with the name of the painter below the image:
After six Crosses, they saw (let’s say) six works by Braque, again for three seconds each with the artist’s name below; then six by YeiMei; and so on. Kornell and Bjork called this blocked practice, because the students studied each artist’s works in a set.
The other half of the participants studied the same paintings for the same amount of time (three seconds per piece), also with the artist’s name below. But in their case, the paintings were not grouped together by artist; they were mixed up:
Both groups studied a total of six paintings from each of the twelve artists. Which group would have a better handle on the styles at the end?
Kornell and Bjork had the participants count backward from 547 by threes after studying—a distraction that acted as a palette cleanser, a way to clear short-term memory and mark a clean break between the study phase and the final test. And that test—to count as a true measure of performance—could not include any of the paintings just studied. Remember, the participants in this study were trying to learn painting styles, not memorize specific paintings. If you “know” Braque, you should be able to identify his touch in a painting of his you’ve never seen before. So Kornell and Bjork had the students view forty-eight un-studied landscapes, one at a time, and try to match each one to its creator, by clicking on one of the twelve names. The researchers weren’t sure what to expect but had reason to suspect that blocked study would be better. For one thing, no one understands exactly how people distinguish artistic styles. For another, similar studies back in the 1950s, having subjects try to learn the names of abstract drawings, found no differences. People studying the figures in blocked sets did every bit as well as those studying mixed sets.
How We Learn Page 16