Chapter 10: What the Marshmallow Test Really Showed

A Father's Worry

Tiago is thirty-eight and works as an electrician. His son, Nuno, is five. One evening, Tiago read an article online about a famous psychology experiment. In the experiment, the article said, young children were offered a choice: they could eat one sweet now, or wait alone in a room for a while and receive two sweets. The article claimed that children who waited longer went on to do better in life: better at school, healthier and more successful as adults. The article ended by suggesting that parents could test their own children at home.

Tiago was curious, and a little worried. The next day, he sat Nuno at the kitchen table with a biscuit in front of him and explained that if Nuno waited until Tiago came back, he could have two biscuits. Then Tiago left the room. Through the gap in the door, he watched. Nuno looked at the biscuit, touched it, smelled it, licked it and, after about two minutes, ate it. When Tiago came back, Nuno looked guilty and said, "I was hungry."

That evening, Tiago could not stop thinking about it. Two minutes. The article had said that children who waited longer did better in life. Did this mean that Nuno would struggle at school? That he lacked self-control? That his future was already decided? Tiago felt a knot of anxiety in his stomach. He began to imagine all the ways his son's inability to wait for a biscuit might shape his life.

When Tiago mentioned his worry to his sister, who teaches young children, she laughed gently. "That article is very out of date," she said. "And a five-year-old eating a biscuit when his father leaves the room tells you very little. Did you know that the same researchers found that children could wait much longer if they were shown how? And that later studies found the link with later life was much smaller than people thought?"

The experiment Tiago read about is one of the most famous in the history of psychology. It is often called the marshmallow test, because marshmallows were among the treats used. It has been described in countless books and articles, often as proof that self-control is a fixed trait that decides our future. This chapter looks at what the research actually found, and why the full story is much more interesting, and much more hopeful, than the popular version.

The Original Studies

The original studies were carried out in the late 1960s and early 1970s at a preschool connected with a university. Young children, mostly around four or five years old, were shown a treat, such as a marshmallow, a biscuit or a pretzel. They were told that they could eat one treat now, or wait until the researcher returned and receive two. The researcher then left the room. If the child rang a bell, the researcher would return, and the child could eat one treat. If the child waited without ringing until the researcher returned after a set time, the child received two.

An important point, often forgotten in popular accounts, is that these studies were mainly about how children manage to wait, not about predicting their future. The researchers tried many variations. In some, the treat was visible. In others, it was covered. In some, children were given suggestions about what to think about while waiting. The findings were clear. Children waited much longer when the treat was hidden from view. They waited longer when they distracted themselves, for example by singing, playing with their hands or covering their eyes. And they waited longer when they were encouraged to think about the treat in a different way, for example imagining a marshmallow as a fluffy white cloud rather than as something sweet and delicious to eat.

In other words, the original studies showed that waiting was not simply a matter of a child having or not having self-control. It depended heavily on the situation and on the strategies the child used. A child who stared at the marshmallow and thought about how delicious it was found waiting very hard. The same child, with the marshmallow hidden or with a strategy for thinking about something else, could often wait much longer.

This connects directly with what we have learned in earlier chapters. The marshmallow on the table is a powerful cue, like the biscuit tin in Matilde's kitchen or the phone in Florin's hand. Hiding it reduces the cue. Distraction moves attention away from it. Thinking about it differently changes its pull. These are the same strategies that help adults with their habits: changing the environment, redirecting attention and changing how we see the temptation.

So the first lesson of the marshmallow research is not that some children are doomed. It is that self-control can be supported by the situation and by learnable strategies. This is a far more useful lesson for parents, teachers and anyone trying to change their own habits.

The Follow-Up and the Later Questions

Years later, the researchers contacted some of the children who had taken part in the original studies, by then teenagers and later adults. They found that, on average, children who had waited longer as preschoolers tended to do somewhat better on various measures later in life, such as school test scores and ratings of how well they coped with stress. These follow-up findings received enormous attention and became the basis of the popular story that Tiago read.

But there were reasons for caution. The original groups of children were fairly small, and they came mostly from families connected with one university, who were not typical of the wider population. Many of the children could not be contacted later, so the follow-up included only some of them. And the studies could show a link between waiting and later outcomes, but not what caused that link.

Much later, a team of researchers carried out a larger study with a more varied group of children, from many different family backgrounds. They also gave children a version of the waiting task and looked at how they were doing years later. They found that there was still a link between waiting and later achievement, but it was much smaller than the earlier follow-ups had suggested. And when they took into account the children's family backgrounds and their early abilities, such as language and attention, the link became smaller still. Much of what had looked like the effect of self-control seemed to be explained by these other factors.

Another study added a different kind of insight. Before the waiting task, some children were given an experience with a researcher who was unreliable: the researcher promised them better art materials and did not deliver. Other children were given an experience with a researcher who kept their promises. Afterwards, in the waiting task, children who had experienced the unreliable researcher waited much less, on average, than those who had experienced the reliable one. This suggests that waiting depends partly on whether children believe the promised reward will actually come.

This last finding is important. For a child who has learned that adults keep their promises, waiting for a second marshmallow makes sense. For a child who has learned that promises are often broken, or that food and other good things may disappear if not taken quickly, eating the marshmallow now is a reasonable choice, not a failure of self-control. The research suggests that what looks like impulsiveness may sometimes be a sensible response to an unreliable world.

It is worth noticing how the story of the marshmallow research changed over time. The early studies were careful and interesting. The follow-ups were intriguing but based on small groups. Popular accounts then simplified them into a dramatic claim about destiny. Later research, with larger and more varied groups, made the claim much more modest. This pattern, from early excitement to later correction, is common in science, and it is one reason to treat dramatic popular claims with some caution, especially when they concern children.

Tiago Looks Again

After talking with his sister and reading more carefully about the research, Tiago felt his anxiety ease. He realized that his home test had told him almost nothing. Nuno had been hungry, the biscuit had been right in front of him, he had no strategy for waiting and he had no particular reason to think that waiting was important. Like most five-year-olds in that situation, he had eaten the biscuit.

Tiago also felt a little embarrassed about how quickly he had jumped from one biscuit to a whole future. He realized that the article had played on a very natural fear that many parents share: the fear that some small sign in childhood reveals a hidden problem that will shape everything. Understanding the research more fully did not remove his wish to help Nuno grow. But it replaced fear with practical ideas, which felt much better.

Tiago also realized that, if he wanted to help Nuno learn to wait, the research suggested practical ways to do it. He could make waiting easier by removing temptations from view. He could teach Nuno simple strategies for waiting, such as singing a song, playing a game or thinking about something else. And, perhaps most importantly, he could make sure that when he promised something, he kept his promise, so that Nuno learned that waiting was worthwhile.

Tiago began to use these ideas in small ways. When Nuno wanted a treat before dinner, Tiago put the treat on a high shelf, out of sight, and suggested that they play a game while dinner cooked. When Nuno had to wait for something, Tiago sang silly songs with him or asked him to count red cars out of the window. And Tiago made a point of keeping his small promises: if he said they would go to the park after lunch, they went.

Over the following months, Tiago noticed that Nuno became better at waiting in everyday situations. It was not that his son had suddenly gained more self-control. It was that the situations had become easier, he had learned some strategies and he trusted that waiting would be rewarded. "I was ready to decide his whole future from one biscuit," Tiago says. "Now I know that waiting is something you can learn, and something the people around you can help with."

Tiago's story is a reminder to be careful with simplified accounts of famous research. The popular version of the marshmallow test told a story of fixed traits and predetermined futures. The fuller research tells a story of strategies, environments and trust, all of which can be changed.

Akosua and the Long Course

Akosua is twenty-six and works in a call centre. She wants to become a qualified laboratory technician, which requires completing a two-year evening course while she continues working. The rewards of the course, a better job and more interesting work, are far in the future. The costs, tired evenings, less free time and less money for treats, are immediate. Several times, she has nearly given up.

Akosua's challenge is a grown-up version of the marshmallow test: choosing a larger reward later over smaller pleasures now. When she read about the original studies, she was struck by the strategies the children had used. Could she use them too? She decided to try.

First, she reduced the visibility of the immediate temptations, as the children did when the marshmallow was hidden. She stopped walking past her friends' favourite bar on her way to her evening classes, taking a different route. She kept her study materials, not her television remote, on her table at home. Second, she found ways to distract herself during the hardest moments, such as the tired walk to class, by listening to music she loved.

Third, and most powerfully, she changed how she thought about the future reward. Instead of seeing it as something vague and distant, she made it vivid and concrete. She visited a laboratory where technicians worked and talked with them about their jobs. She put a photograph of a laboratory on her fridge. She also broke the long course into small parts, celebrating the end of each term with a small treat, so that rewards came more often. This made the long wait feel more like a series of shorter waits.

Akosua is now in her second year of the course. She still has tired evenings when she wants to give up. But she has learned that waiting is not simply a matter of forcing herself to endure. "The children in those studies did not wait by staring at the marshmallow," she says. "They waited by thinking about something else, or seeing it differently. That is what I do now." Her story shows that the strategies found in the original research apply to adults as well as children.

Hakan and the Reliable Workplace

Hakan is forty-five and recently started a new job in the maintenance department of a large hospital. In his previous job, at a company that had gone through many reorganizations, he had learned not to plan far ahead. Promised training never happened. Promised promotions were cancelled. Projects he worked hard on were dropped halfway. He had developed a habit of focusing only on the immediate: doing what was needed today, without investing in the future.

In his new job, Hakan's manager suggested that he take a course to learn about the hospital's new heating and ventilation systems, which would lead to a more senior role in a year. Hakan was reluctant. His experience told him that such promises were rarely kept, and that effort invested in the future was usually wasted. He preferred to do his daily work well and not think about the rest.

When Hakan read about the study in which children waited less after experiencing an unreliable adult, he recognized himself. His reluctance to invest in the future was not laziness or lack of ambition. It was a reasonable response to years of broken promises. Like the children, he had learned that waiting for a larger reward was risky, because the reward might never come.

Hakan decided to test whether his new workplace was different. He talked openly with his manager about his past experience and asked for specific details about the course and the senior role. His manager gave him clear information and showed him examples of colleagues who had followed the same path. Over the following months, Hakan saw that promises in his new workplace were usually kept. Slowly, his trust grew, and he enrolled in the course.

"I thought something was wrong with me," Hakan says. "I could not make myself plan ahead. But I had just learned, very well, that planning ahead was pointless. When I found a place where it was not pointless, I could do it again." Hakan's story shows that our willingness to wait for future rewards depends partly on our experience of whether those rewards arrive. Reliable environments make patience possible.

Hakan's experience also has a lesson for people who lead others. Managers, teachers and parents often wonder why the people they lead do not invest in the future: why staff do not take up training, why pupils do not work toward long-term goals, why children grab what they can. Sometimes the answer lies partly in the past reliability of the people and systems around them. Keeping promises, following through on plans and being consistent can, over time, make it reasonable for others to wait and to invest.

Practical Steps: Learning to Wait

The first step is to hide the marshmallow. If you are trying to choose a larger reward later over a smaller one now, reduce the visibility of the immediate temptation. Keep it out of sight, out of reach or off your usual route. The original research found that hiding the treat was one of the most powerful ways to help children wait.

The second step is to distract yourself during the hardest moments. When the pull of the immediate reward is strongest, turn your attention to something else: music, conversation, a game, a walk, a task that absorbs you. Distraction is not weakness. It is one of the strategies that helped children wait longest.

The third step is to change how you see the temptation. Like the children who imagined marshmallows as clouds, try thinking about the immediate temptation in a less appealing way, or focusing on its less attractive features. At the same time, make the future reward more vivid and concrete, as Akosua did with her photograph and her visit to a laboratory.

The fourth step is to break long waits into shorter ones. Long delays are hard. Breaking them into stages, with small rewards along the way, can make them more manageable. Celebrate the end of each stage, so that rewards come more often.

The fifth step is to build trust in your own promises. If you often promise yourself rewards that you do not give, or make plans that you abandon, you may teach yourself that waiting is not worthwhile. Try to keep the promises you make to yourself, especially small ones. This builds a sense that future rewards are real.

The sixth step is to notice when your environment is unreliable. If you find it hard to invest in the future, ask whether your experience has taught you that future rewards often fail to come. If so, your difficulty may be a reasonable response, not a personal failing. Look for reliable environments and people, and, if you lead or care for others, try to be reliable for them.

Self-Control Is Not Destiny

The most important lesson of the full marshmallow research is that a child's ability to wait at four years old does not fix their future. The later, larger study found that the link between waiting and later achievement was much smaller than first thought, and was largely explained by family background and early abilities. Waiting depended on situations, strategies and trust, all of which can change. Children who find waiting hard at four are not doomed, and adults who find delay difficult are not condemned to fail.

It is also important to be careful about testing children at home, as Tiago did, and drawing conclusions. A single test, in an informal setting, with a hungry child, tells us very little. Labelling children as having good or poor self-control can be harmful, because children may come to believe the label. It is far more helpful to create supportive situations, teach strategies and be reliable.

Finally, the research reminds us that circumstances matter. Children, and adults, who live with uncertainty, poverty or unreliable support may reasonably choose immediate rewards, because experience has taught them that future rewards are uncertain. Blaming them for lack of self-control misses the point. The more useful response is to make their circumstances more reliable and supportive. This is true for families, schools, workplaces and whole communities.

And as always, if difficulties with impulsive behaviour are severe, persistent and harmful, in a child or an adult, it may be helpful to seek advice from a doctor or another qualified professional, who can look at the whole picture and suggest appropriate support.

A Short Exercise: Your Waiting Toolkit

This exercise helps you prepare strategies for a situation in which you want to choose a larger reward later over a smaller one now. It takes about fifteen minutes.

At the top of a page, write the larger, later reward you want: for example, "finishing my course", "being fitter by summer", "having a calm evening instead of an argument". Below it, write the smaller, immediate temptation that tends to get in the way: "going out with friends on class nights", "skipping exercise to watch television", "replying sharply when I am annoyed".

Then write four headings, one for each of the strategies from the research. Under "Hide", write one way to make the immediate temptation less visible or less easy to reach. Under "Distract", write one activity you could turn to during the hardest moments. Under "See differently", write one way of making the temptation less appealing and one way of making the future reward more vivid. Under "Shorter waits", write one way of breaking the long wait into stages, with a small reward at each stage.

Finally, write one sentence about trust: a promise you will make to yourself and keep, to show that waiting is worthwhile. For example: "When I finish this term, I will take a weekend trip, and I will actually take it." Keep the page and look at it when the immediate temptation is strong.

Akosua did this exercise in the first term of her course. Under "Hide", she wrote "different route, past the library instead of the bar". Under "Distract", she wrote "my favourite music on the walk to class". Under "See differently", she wrote "photograph of a laboratory on the fridge". Under "Shorter waits", she wrote "a small treat at the end of each term". Her promise was: "A day at the seaside when I pass the first year." She kept it.

Chapter Summary

The marshmallow test is a famous series of studies, begun in the late 1960s and early 1970s, in which young children could eat one treat now or wait to receive two. The original studies were mainly about how children manage to wait, and found that hiding the treat, distracting themselves and thinking about it differently helped them wait much longer. Later follow-ups linked longer waiting to some later outcomes, but a later, larger and more varied study found the link much smaller and largely explained by family background and early abilities. Another study found that children waited less after experiencing an unreliable adult.

Tiago and his worried test of his son, Akosua and her long course and Hakan in a reliable new workplace all found that waiting is not a fixed trait but depends on situations, strategies and trust, all of which can be changed. Self-control is not destiny. Simplified accounts of famous research can mislead, testing and labelling children is unwise and difficult circumstances can make immediate rewards a reasonable choice.

In the next chapter, we will look at another practical approach to building habits: starting with changes so small that they seem almost too easy.