How We Learn (20 page)

Lewin was a charismatic, open-minded man who attracted a loyal following of younger students, whom he often met, after hours, at a café near campus. It was a less formal setting than his office, a place to brainstorm over coffee or beer, and one afternoon he noticed something curious. Lewin was meeting with a student of his, Bluma Zeigarnik, a young Lithuanian in search of a research project. On that afternoon one of the two—accounts vary—noticed something about the café’s waiters: They never wrote down orders. They kept them in their head, adding items mentally—… another espresso … a cup of tea … a slice of kuchen …—
until the bill was paid.

Yet once the bill was paid—if,
after
paying, you questioned what was on the tab—they’d have forgotten the entire order. No recollection at all. It was as if, once that order was settled, the waiter’s mind checked off the box and moved on, dropping the entire experience from memory. Lewin and Zeigarnik both knew that this wasn’t a matter of orders falling out of what scientists call short-term memory,
the thirty seconds or so during which we can hold, say, a phone number in mind. The waiters could remember orders for a half hour, sometimes longer.

What was going on here mentally?

Lewin and Zeigarnik came up with a hypothesis: Perhaps unfinished jobs or goals linger in memory longer than finished ones. If nothing else, Zeigarnik now had her research project. She put the question more specifically: What’s the difference in memory between an interrupted activity and an uninterrupted one?

She recruited 164 students, teachers, and children to take part in an experiment and told them they’d be given a series of assignments “to complete
as rapidly and correctly as possible.” The assignments came one at a time and consisted of tasks like making a box out of a sheet of cardboard, sculpting a dog out of clay, or solving a word puzzle. Most of the subjects could complete them in three to five minutes—when allowed to, that is. Zeigarnik periodically interrupted their work, stopping them in the middle of an assignment and giving them another one to work on instead. The interruptions were random, and without explanation.

At the end—after eighteen to twenty-two assignments, some interrupted and left unfinished and some not—Zeigarnik asked the test subjects to write down as many of those assignments as they could remember. Those lists told the story: On average, participants remembered 90 percent more of the interrupted and unfinished assignments than the ones they’d completed. Not only that, the interrupted and unfinished jobs were at the top of their lists—the first ones they wrote down. The completed ones, if remembered at all, came at the end. “So far as amount of time is concerned, the advantage
should
lie with completed tasks, since a subject who completed a task naturally spent a longer time with it than one who did not,” Zeigarnik wrote.

Was it possible, she wondered, that the “shock” of being interrupted makes an experience more memorable?

Zeigarnik performed another version of the study on a new group of participants. This time every assignment the subjects worked on was interrupted. Some of the assignments were completed, after a short break; others were not. The results, however, were nearly identical in one characteristic to the first experiment: People remembered about 90 percent more of the small jobs they
hadn’t
finished. Running still more trials, Zeigarnik found that she could maximize the effect of interruption on memory by stopping people at the moment when they were most engrossed in their work. Interestingly, being interrupted at the “worst” time seemed to extend memory the longest. “As everyone knows,” Zeigarnik wrote, “it is far more disturbing to be interrupted just before finishing a letter than when one has only begun.”

Once people become absorbed in an assignment, they feel an urge to finish, and that urge builds as the job moves closer to completion. “The desire to complete the task may at first have been only a quasi-need,” she concluded, “but later, through losing oneself in the task,
a genuine need arises.”

In 1931, soon after publishing her work on interruption, Zeigarnik moved to Moscow with her husband, Albert, who had taken a position at the Soviet Ministry of Foreign Trade. She secured a job at the prestigious Institute of Higher Nervous Activity. Their good fortune didn’t last, however. In 1940, Albert was arrested on charges of spying for Germany and sent to a prison camp in Lubyanka, leaving Bluma in Moscow to manage a job and two young children. She continued to work as a psychologist, gradually cut off ties with Western colleagues to avoid any taint of suspicion, and died in 1988, leaving behind virtually no trace of her research. (A relative, A. V. Zeigarnik, believes she
destroyed her papers.)

Yet the implications of her work survived, and then some. The Zeigarnik effect, as it’s now known, became a foundational contribution to the study of goals and goal formation.

When we think about goals, we tend to think in terms of dreams.
Restoring a classic car. Living abroad. Starting a business. Writing a novel. Running a marathon. Being a better dad. Finding a stable relationship. For psychologists, however, a goal isn’t nearly so grand. A goal is anything we want to possess or achieve and haven’t yet, whether it’s short-term or long-term, getting a Ph.D. or getting dressed. According to that definition, our heads are full of goals every waking minute, and they’re all competing for our attention. Should we walk the dog, or make coffee first? Help Junior pack for camp, or catch up on some work? Go to the gym, or practice Spanish?

Zeigarnik’s studies on interruption revealed a couple of the mind’s intrinsic biases, or built-in instincts, when it comes to goals. The first is that the act of starting work on an assignment often gives that job the psychological weight of a goal, even if it’s meaningless. (The people in her studies were doing things like sculpting a dog from a lump of clay, for heaven’s sake; they got nothing out of it but the satisfaction of finishing.) The second is that interrupting yourself when absorbed in an assignment extends its life in memory and—according to her experiments—pushes it to the top of your mental to-do list.

Most interruptions are annoying—especially if it’s a busybody neighbor, or the cat needing to be let out, or a telemarketer calling when you’re in the middle of an important work assignment. But deliberate
self
-interruption is something else altogether. It’s what Dickens did so well in his novels, with cliff-hanger endings for each chapter. Or what TV writers do when closing out one season and priming the audience for the next. The final episode ends with a scream, footsteps in a dark corridor, a relationship unexpectedly soured or kindled.

This kind of interruption creates suspense and, according to the Zeigarnik effect, pushes the unfinished episode, chapter, or project to the top of our minds, leaving us to wonder what comes next. Which is exactly where we want it to be if we’re working on something long-term and demanding.

The first element of percolation, then, is that supposed enemy of learning—interruption.

• • •

The Bisaldrop Dubbel Zoute is a Dutch black licorice drop the size of a plug nickel. Bisaldrops are an acquired taste, slightly sweet and very salty, and best served with a cool glass of water. For our purposes, the important thing to know is that Bisals make you thirsty—and fast—which is why a group of scientists in the Netherlands used them in a 2001 experiment to measure
the effect of goals on perception. The group, led by the psychologist Henk Aarts at Leiden University, began their trial the way so many scientists do: by lying. Researchers often attempt to disguise a study’s true purpose so participants don’t just play along or deliberately undermine the results. In this case, Aarts recruited eighty-four undergraduates for what he described as a study of, get this, “how well people can detect letters with their tongue under different taste conditions.”

The students were divided into two groups. One group got three Bisaldrops, each branded with a letter. They had a minute to eat each candy and try to name the letter printed on it. The other group—the control group—received no candy at all; they were given instructions to trace three simple figures on paper, a form of busywork that had nothing to do with the study’s aim. Afterward, the experimenter led the participants, one at a time, into a room he described as his office, to fill out a one-minute questionnaire on unrelated topics (“What is your favorite activity to relax?” and the like). The questions had nothing to do with the aim of the study, either. The room itself did. It looked like your standard academic office: a small space with a chair and desk, papers, books, pencils, a stack of folders, and a computer. Scattered about were several drink-related items, too—a water bottle, a glass, cups, an empty soda can. After finishing the questionnaire, each participant sat in that office, by him-or herself, for four minutes.

The experimenter then returned and brought the person back to the lab room for a surprise quiz. Each participant was given four minutes to write down as many objects in the office as he or she could remember. By this time, the participants must have been wondering what on earth this had to do with detecting letters with their tongues—let alone science—but they did as they were told. Some recalled only one item, and others a half dozen. Nothing surprising there; some participants were likely daydreaming for those four minutes and others scanning the bookshelves. It was
what
they wrote down that the psychologists were interested in, and that’s where a significant difference became clear: The group that had been given the Bisaldrops remembered twice as many drink-related items as the control group. They were thirsty, and that influenced what they noticed in the office and remembered later, even if they weren’t aware
why
they recalled those things.

The experiment was a clever demonstration of a fairly straightforward principle of social psychology: Having a goal foremost in mind (in this case, a drink), tunes our perceptions to fulfilling it. And that tuning determines, to some extent, where we look and what we notice. “The results suggest that basic needs and motives cause a heightened perceptual readiness to register environmental cues that are instrumental to satisfying those needs,” the authors concluded. “It can foster the reduction of thirst by helping us to detect a can of Coke or a cool glass of beer that would go unnoticed
under other circumstances.”

On the surface, this is common sense, right? Of
course
we look for a drinking fountain when we’re thirsty, or a snack machine when hungry. Keep in mind, though, that the thirsty students in this study were more likely than the others to notice not just bottles of water or cans of soda but
anything
in the room that was drink-related—a cup, a saucer, a bottle cap. Whether they were aware of it or not, their thirst activated a mental network that was scavenging the landscape for anything linked to liquid.

In dozens of studies going back decades, psychologists have shown that this principle of tuned perception applies not only to elemental needs like thirst, but to any goal we hold foremost in mind. This is a familiar experience, too. As soon as we decide to buy a certain brand of handbag or model of smartphone or style of jeans, we begin seeing that product far more often than we had before, in stores, at the mall, walking down the street. I remember the first time this phenomenon occurred to me. I was eleven years old, and I’d just bought my first pair of Converse All-Stars, which were standard issue, way back when, for boys my age. But I didn’t want the usual colors, white or black; no, the ones I wanted were green. Bright kelly green. I remember bringing them home and putting them on and going out into the world, and suddenly feeling like, hey, wait a minute: Those sneakers were
everywhere
. I must have counted a half dozen pairs of green ones the first day I wore them. Not only that, I started to notice other, more exotic colors, as well as different styles and laces. Within weeks, I had a detailed mental map of a particular subculture: preteen Converse wearers in 1971 suburban Chicago, a subtle, intricate universe that was previously invisible to me. And I did this without “studying” at all—at least, not in the usual sense.

What does this have to do with finishing a research paper on, say, the Emancipation Proclamation? Everything, actually. Academic pursuits are goals, too, and they can tune our perceptions in the same way that a powerful thirst or a new pair of sneakers can. When we’re
in the middle of that paper, for example, we’re far more attuned to race references all around us. A story about race riots or affirmative action in the media. An offhand comment by a friend. A review of a Lincoln biography in the newspaper. Even the way people of different races arrange themselves at a bar, or on a subway car. “Once a goal becomes activated, it trumps all others and begins to drive our perceptions, our thoughts, our attitudes,” as John Bargh, a psychologist at Yale University, told me.

So the question is: How, then, do we most effectively activate that goal?

By interrupting work on it at an important and difficult moment—propelling the assignment, via the Zeigarnik effect, to the top of our mind.