Psychology says children who fail the marshmallow test may be showing more about their home life than their willpower

Imagine placing one marshmallow in front of a four-year-old and telling them they can eat it now or wait until an adult returns to receive a second one. Some children wait patiently. Others reach for the treat almost immediately. This simple experiment, known as the marshmallow test, became one of psychology’s best-known ways of studying delayed gratification, or the ability to resist an immediate reward for a larger one later.For years, the test was widely discussed as a measure of a child’s self-control and even as a possible clue to future success. But later research has added an important dimension to the conversation: a child’s decision may also reflect what they have learnt about the world around them. If promises are not always kept or circumstances are unpredictable, waiting may not seem like a sensible choice. In other words, eating the marshmallow does not automatically mean a child lacks discipline. It may tell us something about the situation in which the child is growing up.

The experiment that made one marshmallow famous

The original research was conducted by psychologist Walter Mischel and his colleagues at Stanford University in the 1960s and 1970s. Preschool children were offered a choice between a smaller reward immediately and a larger reward if they could wait until the researcher returned. Researchers later followed some of the children and reported links between their ability to wait and outcomes such as academic performance and behaviour. These findings helped turn the experiment into a popular lesson about patience, willpower and long-term achievement.However, the original follow-up studies involved relatively small and selective groups. This meant their findings could not automatically be applied to every child or family. The test also measures behaviour in one particular situation. A child’s response can be influenced by their age, understanding of the instructions, mood, hunger and whether they feel comfortable with the adult conducting the experiment. It cannot provide a complete picture of a child’s personality or abilities.

What happens when a child does not trust the promise?

A particularly interesting study by researchers Celeste Kidd, Holly Palmeri and Richard Aslin, published in the journal Cognition in 2013, examined whether children’s decisions were influenced by how reliable their surroundings appeared to be. Before the marshmallow test, children experienced an interaction in which an adult either kept a promise or failed to deliver what had been promised. The researchers then observed how long the children waited for the larger reward.The difference was striking. Children who experienced a reliable adult waited considerably longer than those who had experienced an unreliable one. The findings suggested that children were not simply struggling to control an impulse. They were also responding to what they had learnt about whether waiting would actually be worthwhile.Think about it from a child’s perspective. If an adult repeatedly promises something and does not follow through, taking the available reward may seem more practical than trusting another promise. What looks like impatience to an observer may be a response to uncertainty. This does not mean every child who eats the marshmallow has experienced an unreliable home. It shows that the behaviour can be shaped by the immediate environment, not just by an internal ability to exercise self-control.

Why family background changes the interpretation

A major 2018 study by Tyler Watts, Greg Duncan and Haonan Quan revisited the long-term claims associated with the marshmallow test. Published in Psychological Science, it examined a larger and more diverse group of children than the original follow-up research. The researchers found that the relationship between waiting time and later academic achievement became much smaller after they accounted for factors such as family background, early cognitive ability and the home environment. The associations with later behavioural outcomes were also much weaker than earlier research had suggested.This does not mean self-control is unimportant. Rather, it suggests that a child’s ability to wait should not be treated as an isolated quality that determines their future. Their experiences, opportunities and the support available to them also matter. A 2020 analysis by Laura E. Michaelson and Yuko Munakata offered another perspective. It found that some links between early delay of gratification and later behaviour were better explained by social support than by self-control alone. Together, these studies encourage a broader understanding of children’s development.

What parents can take away from the marshmallow test

The most useful lesson for parents is not to train children to wait for longer simply to prove they have willpower. It is to create everyday experiences that help them feel secure, understand expectations and practise self-regulation. Parents can begin with small, age-appropriate activities. Taking turns during a game, waiting briefly for a snack, completing a simple puzzle or following a two-step instruction can give children opportunities to practise patience and problem-solving.Keeping promises also matters. If a parent tells a child they will play together after dinner, following through whenever possible helps build trust. When plans have to change, explaining the reason can help children understand that a delay does not mean a promise has been forgotten. It is equally important not to compare siblings or label a child as impatient because they struggle with one task. Young children are still developing the ability to manage emotions and impulses, and their responses can vary from day to day.The marshmallow test began as an experiment about waiting for a sweet. Its larger lesson is about looking beyond a single action before judging a child. Sometimes, understanding why a child makes a choice tells us far more than the choice itself.