The Marshmallow Test and self-control

 INTRODUCTION

AS BOTH MY STUDENTS and my children can testify, self-control does not come naturally to me. I have been known to call my students in the middle of the night to ask how the latest data analysis was going, though it began only that evening. At dinners with friends, to my embarrassment my plate is often the first to be clean, when others are far from done. My own impatience, and the discovery that self-control strategies can be learned, has kept me studying those strategies for a lifetime.

The basic idea that drove my work and motivated me to write this book was my belief, and the findings, that the ability to delay immediate gratification for the sake of future consequences is an acquirable cognitive skill. In studies initiated half a century ago, and still ongoing today, we’ve shown that this skill set is visible and measurable early in life and has profound long-term consequences for people’s welfare and mental and physical health over the life span. Most important, and exciting for its educational and child-rearing implications, it is a skill open to modification, and it can be enhanced through specific cognitive strategies that have now been identified.

The Marshmallow Test and the experiments that have followed over the last fifty years have helped stimulate a remarkable wave of research on self-control, with a fivefold increase in the number of scientific publications just within the first decade of this century. In this book I tell the story of this research, how it is illuminating the mechanisms that enable self-control, and how these mechanisms can be harnessed constructively in everyday life.

It began in the 1960s with preschoolers at Stanford University’s Bing Nursery School, in a simple study that challenged them with a tough dilemma. My students and I gave the children a choice between one reward (for example, a marshmallow) that they could have immediately, and a larger reward (two marshmallows) for which they would have to wait, alone, for up to 20 minutes. We let the children select the rewards they wanted most from an assortment that included marshmallows, cookies, little pretzels, mints, and so on. “Amy,” for example, chose marshmallows. She sat alone at a table facing the one marshmallow that she could have immediately, as well as the two marshmallows that she could have if she waited. Next to the treats was a desk bell she could ring at any time to call back the researcher and eat the one marshmallow. Or she could wait for the researcher to return, and if Amy hadn’t left her chair or started to eat the marshmallow, she could have both. The struggles we observed as these children tried to restrain themselves from ringing the bell could bring tears to your eyes, have you applauding their creativeness and cheering them on, and give you fresh hope for the potential of even young children to resist temptation and persevere for their delayed rewards.

What the preschoolers did as they tried to keep waiting, and how they did or didn’t manage to delay gratification, unexpectedly turned out to predict much about their future lives. The more seconds they waited at age four or five, the higher their SAT scores and the better their rated social and cognitive functioning in adolescence. At age 27–32, those who had waited longer during the Marshmallow Test in preschool had a lower body mass index and a better sense of self-worth, pursued their goals more effectively, and coped more adaptively with frustration and stress. At midlife, those who could consistently wait (“high delay”), versus those who couldn’t (“low delay”), were characterized by distinctively different brain scans in areas linked to addictions and obesity.

What does the Marshmallow Test really show? Is the ability to delay gratification prewired? How can it be taught? What is its downside? This book speaks to these questions, and the answers are often surprising. In The Marshmallow Test, I discuss what “willpower” is and what it is not, the conditions that undo it, the cognitive skills and motivations that enable it, and the consequences of having it and using it. I examine the implications of these findings for rethinking who we are; what we can be; how our minds work; how we can—and can’t—control our impulses, emotions, and dispositions; how we can change; and how we can raise and educate our children.

Everybody is eager to know how willpower works, and everybody would like to have more of it, and with less effort, for themselves, their children, and their relatives puffing on cigarettes. The ability to delay gratification and resist temptations has been a fundamental challenge since the dawn of civilization. It is central to the Genesis story of Adam and Eve’s temptation in the Garden of Eden, and a subject of the ancient Greek philosophers, who named the weakness of the will akrasia. Over the millennia, willpower was considered an immutable trait—you either had it or you didn’t—making those low in willpower victims of their biological and social histories and the forces of the momentary situation. Self-control is crucial for the successful pursuit of long-term goals. It is equally essential for developing the self-restraint and empathy needed to build caring and mutually supportive relationships. It can help people avoid becoming entrapped early in life, dropping out of school, becoming impervious to consequences, or getting stuck in jobs they hate. It is the “master aptitude” underlying emotional intelligence, essential for constructing a fulfilling life. And yet, despite its evident importance, it was excluded from serious scientific study until my students and I demystified the concept, created a method to study it, showed its critical role for adaptive functioning, and parsed the psychological processes that enable it.

Public attention to the Marshmallow Test increased early in this century and keeps escalating. In 2006, David Brooks devoted an editorial to it in the Sunday New York Times, and years later in an interview he conducted with President Obama, the president asked Brooks if he wanted to talk about marshmallows. The test was featured in The New Yorker in a 2009 Department of Science article, and the research is widely presented in television programs, magazines, and newspapers throughout the world. It is even guiding the efforts of Sesame Street’s Cookie Monster to master his impulse to voraciously devour cookies so that he may join the Cookie Connoisseurs Club. The marshmallow research is influencing the curriculum in many schools that teach a wide range of children, from those living in poverty to those attending elite private academies. International investment companies use it to encourage retirement planning. And a picture of a marshmallow has become an immediately understood opener to launch discussions of delay of gratification with almost any audience. In New York City, I see kids coming home from school wearing T-shirts that say Don’t Eat the Marshmallows and large metal buttons declaring I Passed the Marshmallow Test. Fortunately, as the public interest in the topic of willpower increases, so does the amount and depth of scientific information on how delay of gratification and self-control are enabled, both psychologically and biologically.

In order to understand self-control and the ability to delay gratification, we need to grasp not only what enables it but also what undoes it. As in the parable of Adam and Eve, we see headline after headline that reveals the latest celebrity—a president, a governor, another governor, a revered judge and moral pillar of society, an international financial and political wizard, a sports hero, a film star—who blew it with a young intern, a housekeeper, or an illegal drug. These people are smart, and not just in their IQ intelligence but emotional and social intelligence as well—otherwise they could not have achieved their eminence. Then why do they act so stupid? And why do they have so much company in the many men and women who never make it into the headlines?

I draw on findings at the vanguard of science to try to make sense of this. At the heart of the story are two closely interacting systems within the human brain, one “hot”—emotional, reflexive, unconscious—and the other “cool”—cognitive, reflective, slower, and effortful. The ways in which these two systems interact in the face of strong temptations underlie how preschoolers deal with marshmallows and how willpower works, or doesn’t. What I learned changed my long-held assumptions about who we are, the nature and expressions of character, and the possibilities for self-generated change.

Part I, Delay Ability: Enabling Self-Control, tells the story of the Marshmallow Test and the experiments that showed preschool children doing what Adam and Eve could not do in the Garden of Eden. The results identified the mental processes and strategies through which we can cool hot temptations, delay gratification, and achieve self-control. They also pointed to possible brain mechanisms that enable these achievements. Decades later, a flood of brain research is using cutting-edge imaging techniques to probe the mind-brain connections and help us understand what the preschooler managed to do.

The marshmallow findings inevitably lead to the question “Is self-control prewired?” Recent discoveries in the science of genetics are providing fresh answers to that question. They are revealing the surprising plasticity of our brains and transforming how we think about the role of nurture and DNA, environment and heredity, and the malleability of human nature. The implications go far beyond the science lab and contradict widely shared beliefs about who we are.

Part I leaves us with a mystery: why does the preschooler’s ability to wait for more treats, rather than ring the bell and settle for less, predict so much about future success and well-being? I answer that question in Part II, From Marshmallows in Pre-K to Money in 401(k), where I look at how self-control ability influences the journey from preschool to retirement planning, how it paves the way to creating successful experiences and positive expectations—an “I think I can!” mind-set and a sense of self-worth. While not guaranteeing success and a rosy future, self-control ability greatly improves the chances, helping us make the tough choices and sustain the effort needed to reach our goals. How well it works depends not just on skills but on internalizing goals and values that direct the journey, and on motivation that is strong enough to overcome the setbacks along the route. How self-control can be harnessed to build such a life by making willpower less effortful and increasingly automatic and rewarding is the story of Part II, and like life itself it unfolds in unexpected ways. I discuss not just resistance to temptation but diverse other self-control challenges, from cooling painful emotions, overcoming heartbreak, and avoiding depression to making important decisions that take future consequences into account. And while Part II shows the benefits of self-control, it makes its limits equally clear: a life with too much of it can be as unfulfilling as one with too little.

In Part III, From Lab to Life, I look at the implications of the research for public policy, focusing on how recent educational interventions beginning in preschool are incorporating lessons on self-control in order to give those children living under conditions of toxic stress a chance to build better lives. I then summarize the concepts and strategies examined throughout this book that can help with everyday self-control struggles. The final chapter considers how findings about self-control, genetics, and brain plasticity change the conception of human nature, and the understanding of who we are and what we can be.

In writing The Marshmallow Test, I imagined myself having a leisurely conversation with you, the reader, much like the many I have had with friends and new acquaintances, sparked by the question “What’s the latest in the marshmallow work?” Soon we veer off into how the findings relate to aspects of our own lives, from child rearing, hiring new staff, and avoiding unwise business and personal decisions to overcoming heartbreak, quitting smoking, controlling weight, reforming education, and understanding our own vulnerabilities and strengths. I have written the book for those of you who, like me, have struggled with self-control. I’ve also written it for those who simply would like to understand more deeply how our minds work. I hope The Marshmallow Test will start some new conversations for you.

***

When we designed the experiment in the 1960s we did not film the children. But twenty years later, to record the Marshmallow Test procedure and to illustrate the diverse strategies children use as they try to wait for their treats, my former postdoc Monica L. Rodriguez filmed five-to six-year-olds with a hidden camera in a public school in Chile. Monica followed the same procedure we had used in the original experiments. First up was “Inez,” an adorable little first grader with a serious expression but a twinkle in her eye. Monica seated Inez at a small table in the school’s barren research room. Inez had chosen Oreo cookies as her treats. On the table were a desk bell and a plastic tray the size of a dinner plate, with two cookies in one corner of the tray and one in the other corner. Both the immediate and the delayed rewards were left with the children, to increase their trust that the treats would materialize if they waited for them as well as to intensify their conflict. Nothing else was on the table, and no toys or interesting objects were available in the room to distract the children while they waited.

Inez was eager to get two cookies rather than just one when given the choice. She understood that Monica had to go out of the room to do some work but that she could call her back at any time by ringing the bell. Monica let Inez try ringing it a couple of times, to demonstrate that each time she rang Monica would immediately come back in the room. Monica then explained the contingency. If Inez waited for her to come back by herself, she got the two cookies. If she did not want to wait, she could ring the bell at any time. But if she rang the bell, or began to eat the treat, or left the chair, she’d get only the single cookie. To be sure that Inez understood the instructions fully, she was asked to repeat them.

When Monica exited, Inez suffered for an agonizing few moments with an increasingly sad face and visible discomfort until she seemed about to burst into tears. She then peeked down at the treats and stared hard at them for more than ten seconds, deep in thought. Suddenly her arm shot out toward the bell but just as her hand got to it, she stopped herself abruptly. Gingerly, tentatively, her index finger hovered above the bell’s ringer, almost but not quite touching it, over and over, as if to tease herself. But then she jerked her head away from the tray and the bell, and burst out laughing, as if she had done something terribly funny, sticking her fist into her mouth to prevent herself from roaring aloud, her face beaming with a self-congratulatory smile. No audience has watched this video without oohing and laughing along with Inez in empathic delight. As soon as she stopped giggling, she repeated her teasing play with the bell, but now she alternately used her index finger to shush herself and stuck her hand in front of her carefully closed lips, whispering “No, no” as if to stop herself from doing what she had been about to do. After 20 minutes had passed, Monica returned “by herself,” but instead of eating the treats right away, Inez marched off triumphantly with her two cookies in a bag because she wanted to take them home to show her mother what she had managed to do.

“Enrico,” large for his age and dressed in a colorful T-shirt, with a handsome face topped by neatly cut blond bangs, waited patiently. He tipped his chair far back against the wall behind him, banging it nonstop, while staring up at the ceiling with a bored, resigned look, breathing hard, seemingly enjoying the loud crashing sounds he made. He kept banging until Monica returned, and he got his two cookies.

“Blanca” kept herself busy with a mimed silent conversation—like a Charlie Chaplin monologue—in which she seemed to be carefully instructing herself on what to do and what to avoid while waiting for her treats. She even mimed smelling the imagined goodies by pressing her empty hand against her nose.

“Javier,” who had intense, penetrating eyes and an intelligent face, spent the waiting time completely absorbed in what appeared to be a cautious science experiment. Maintaining an expression of total concentration, he seemed to be testing how slowly he could manage to raise and move the bell without ringing it. He elevated it high above his head and, squinting at it intently, transported the bell as far away from himself as possible on the desktop, stretching the journey to make it as long and slow as he could. It was an awesome feat of psychomotor control and imagination from what looked like a budding scientist.

Monica gave the same instructions to “Roberto,” a neatly dressed six-year-old with a beige school jacket, dark necktie on his white shirt, and perfectly combed hair. As soon as she left the room he cast a quick look at the door to be sure it was tightly shut. He then rapidly surveyed the cookie tray, licked his lips, and grabbed the closest treat. He cautiously opened the cookie to expose the white cream filling in its middle, and, with bent head and busy tongue, he began to lick the cream meticulously, pausing for only a second to smilingly approve his work. After licking the cookie clean, he skillfully put the two sides back together with even more obvious delight and carefully returned the filling-free cookie to the tray. He then hurried at top speed to give the remaining two cookies the identical treatment. After devouring their insides, Roberto arranged the remaining pieces on the tray to restore them to their exact original positions, and checked the scene around him, scanning the door to be sure that all was well. Like a skilled method actor, he then slowly sank his head to place his tilted chin and cheek on the open palm of his right hand, elbow resting on the desktop. He transformed his face into a look of utter innocence, his wide, trusting eyes staring expectantly at the door in childlike innocent wonder.

Roberto’s performance invariably gets the most cheers and the loudest laughter and applause from every audience, including, once, a congratulatory shout from the esteemed provost of one of America’s top private universities to “get him a scholarship when he’s ready to come here!” I don’t think he was joking.

***

Self-control skills are essential for pursuing our goals successfully, but it is the goals themselves that give us direction and motivation. They are important determinants of life satisfaction, and those we select early in life have striking effects both on the later goals that we reach and the satisfaction we feel about our lives. No matter how they are formed, the goals that drive our life stories are as important as the EF we need to try to reach them.

Self-control, especially when it is labeled “effortful control,” can sound as if it demands a grim commitment to very tough, trying labor—a voluntary entry into a work-driven life of self-denial, of living for the future and missing the pleasures of the moment. An acquaintance told me about a recent dinner he had with friends in Manhattan during which the topic turned to the Marshmallow Test. One of his friends, a novelist who lived in Greenwich Village, was contrasting his own life with that of his brother, a very wealthy and successful investment banker living the pinstriped-suit-with-Hermès-necktie life. The brother had long been married and had children who were all doing well. The writer had published five novels but they had had little impact and few sales. He described himself nevertheless as having a great time, spending his days writing and living the bachelor life at night, going from one short-term relationship to the next. He speculated that his solemn, straight-laced brother probably would have waited forever for his marshmallows, whereas he would have been an early bell ringer.

In fact, the novelist could not have published those five books without a great deal of self-control, and he probably also needs it when trying to maintain his fun relationships while staying uncommitted. Nor did he manage to make it through an elite liberal arts college that emphasizes creative writing without having more than enough self-control to do so. You need EF as much for a creative life in the arts as for a successful life in anything else; it’s just the goals that differ. Without EF, the chance to find and pursue your goals is lost. That’s what the kids in the South Bronx faced if they lost in the KIPP lottery. But without compelling goals and drive, EF can leave us competent but aimless.

ALTERNATIVE VIEWS OF WHO WE ARE

Your reactions to the research findings on brain plasticity and the malleability of behavior in this book depend importantly on your own beliefs about how much people can really control and change what they become. There are two conflicting ways to interpret what these findings tell us in the larger context of who we are and what we can be. It is worth using your cool system to think about what the results mean to you before coming to firm conclusions that your hot system has probably already reached.

The answer to the question of whether human nature is, at its core, malleable or fixed has been an enduring concern of not just scientists but, more important, each of us in our everyday lives. Some people see self-control ability, willpower, intelligence, and other characteristics as fixed, unchangeable traits from the very start of life. They read the experimental evidence that executive function and self-control improve after educational interventions and interpret that as short-term effects unlikely to make a long-term difference, just little tricks that don’t change inborn traits. These people differ from those who see the evidence as supporting the view that we are open to change and able to alter how we think and behave, that we can craft our own lives rather than being either the winners or the losers in the DNA lottery.

If we allow the evidence to make a difference to our personal theories, the discovery of the plasticity of the brain tells us that human nature is more flexible and open to change than has long been assumed. We do not come into the world with a bundle of fixed, stable traits that determine who we become. We develop in continuous interactions with our social and biological environments. These interactions shape our expectations, the goals and values that drive us, the ways we interpret stimuli and experience, and the life stories we construct.

To reiterate from the nature-nurture discussion (Chapter 7), as Kaufer and Francis point out, “Environments can be as deterministic as we once believed only genes could be, and… the genome can be as malleable as we once believed only environments could be.” And the basic message of this book has been that there is substantial evidence that we can be active agents who in part control how those interactions play out. That leaves us with a view of human nature in which we potentially have more choice, and more responsibility, than in the purely deterministic scientific views of the past century. Those views attributed the causes of our behavior to the environment, DNA, the unconscious, bad parenting, or evolution, plus chance. The story this book tells acknowledges all these sources as influences. But ultimately, at the end of that causal chain, it is the individual who is the agent of the action and decides when to ring the bell.

Walter Mischel 

When I am asked to summarize the fundamental message from research on self-control, I recall Descartes’s famous dictum cogito, ergo sum—“I think, therefore I am.” What has been discovered about mind, brain, and self-control lets us move from his proposition to “I think, therefore I can change what I am.” Because by changing how we think, we can change what we feel, do, and become. If that leads to the question “But can I really change?,” I reply with what George Kelly said to his therapy clients when they kept asking him if they could get control of their lives. He looked straight into their eyes and said, “Would you like to?”