In 1968, a psychologist named Walter Mischel set up a small table in a room at Stanford’s Bing Nursery School. On it, he placed a single marshmallow. Then he brought in a four-year-old and made a simple offer.
You can eat this marshmallow now. Or, if you wait until I come back, you can have two.
Then Mischel left the room. And the hidden cameras started rolling.
What happened next became one of the most famous experiments in the history of psychology. Some kids ate the marshmallow before the door even closed. Others squirmed, sat on their hands, sang to themselves, or turned away from the treat. A few waited the full 15 minutes.
Over the next several years, Mischel and his colleagues tested more than 600 children at the Bing School. The original studies ran from 1968 to 1974, generating a rich dataset on how preschoolers handle temptation.
But the study didn’t become legendary until the follow-ups.
The SAT Bombshell
In 1990, Mischel’s colleague Yuichi Shoda published a follow-up that tracked down some of the original marshmallow kids, now teenagers. The results were stunning. Children who had waited longer at age four scored an average of 210 points higher on the SAT than those who grabbed the treat immediately.
The correlations were enormous — r = .57 for math, r = .42 for verbal. In behavioral science, those numbers are jaw-dropping. Mischel later wrote in his book The Marshmallow Test that the ability to delay gratification was “a protective buffer against the development of all kinds of vulnerabilities later in life.”
Parents panicked. Preschool teachers started running their own marshmallow tests. The message seemed clear: if your kid grabs the marshmallow, they’re doomed.
But here’s where the story gets more interesting — and more useful.
The Replication That Changed Everything
In 2018, Tyler Watts at New York University and Greg Duncan at UC Irvine decided to rerun the marshmallow test with a much larger, more diverse sample. Their study, published in Psychological Science, included over 900 children — far more than Mischel’s original group.
The results? Complicated.
Yes, kids who waited longer did score slightly better on achievement tests at age 15. But the effect was roughly half the size Mischel had found. And when Watts and Duncan controlled for family background, early cognitive ability, and home environment, the correlation shrank by two-thirds.
“The association between delay ability and later outcomes was largely explained by the child’s social and economic background,” Watts told The Atlantic. In other words, it wasn’t willpower predicting success. It was privilege.
Think about it from a four-year-old’s perspective. If you grow up in a home where promises get broken — where the second marshmallow never actually arrives — why would you wait? The kids who grabbed the treat weren’t failing a willpower test. They were making a rational decision based on their experience of the world.
What Mischel Actually Discovered (That Everyone Ignores)
Here’s what’s fascinating. Mischel himself never believed willpower was a fixed trait. His original research was actually about strategies. He spent years studying what the successful waiters did differently.
The kids who waited didn’t just white-knuckle it. They used specific techniques. They covered their eyes. They turned the marshmallow into something abstract — pretending it was a cloud, or a picture in a frame. They distracted themselves with songs or games.
Mischel called this “cognitive reappraisal.” And he showed that you could teach it. When researchers coached the impulsive kids to use these strategies, their wait times skyrocketed. The trait that looked fixed was actually a skill.
“The key insight from the marshmallow test is not that some children have willpower and others don’t,” Mischel said in a Long Now Foundation lecture. “It’s that the ability to delay gratification is a set of cognitive skills that can be taught.”
This matters enormously for how you think about yourself and your team.
The Management Mistake
Here’s where most managers get this wrong. They see self-control as a character trait. Someone either has discipline or they don’t. The employee who misses deadlines lacks willpower. The one who procrastinates needs more motivation.
But Mischel’s research — all of it, including the complicated replications — points to a different conclusion. Self-control is less about internal fortitude and more about environment design.
The kids who waited for the marshmallow weren’t tougher. They were better at changing their environment. They turned away from the treat. They sang songs. They created systems that made waiting easier.
You can do the same thing at work. Instead of relying on willpower to ignore your inbox, close the app. Instead of muscling through distractions in an open office, find a quiet room. Instead of expecting your team to resist the urge to context-switch, redesign their workflow so the temptation disappears.
This is exactly what James Clear writes about in Atomic Habits — the idea that small environmental changes beat willpower every time. Mischel’s marshmallow data was the scientific foundation for that insight decades before Clear popularized it.
The Real Lesson of the Marshmallow
The marshmallow test isn’t a story about born winners and born losers. It’s a story about strategy.
Celeste Kidd, a researcher at UC Berkeley who studies child cognition, published a 2013 study showing that children’s willingness to wait was heavily influenced by whether they trusted the environment. When researchers broke promises before the marshmallow test, wait times plummeted. When they kept promises, wait times soared.
“Rational decision-making about the future requires a reliable environment,” Kidd told PBS. “If you have reason to believe the second marshmallow isn’t coming, eating the first one is the smart move.”
That finding has massive implications for leadership. If your team doesn’t trust that delayed rewards will actually arrive — that the promotion will come, that the hard project will be recognized, that the bonus will materialize — they’re not going to wait. And that’s not a character flaw. That’s rational behavior.
What to Do With This
If you manage people, stop thinking about self-control as something your team either has or lacks. Start thinking about three things instead.
First, teach the strategies. Mischel showed that cognitive reappraisal works. Help your team reframe boring tasks, break big goals into smaller pieces, and create mental distance from temptations. These are coachable skills, not personality traits.
Second, design the environment. Remove the marshmallows. If you want deep work, create conditions for it. If you want people to stop checking Slack every three minutes, give them permission to go dark. The best managers don’t rely on their team’s willpower. They make the right behavior the easy behavior.
Third, keep your promises. Kidd’s trust research is the most underrated finding in this entire body of work. If you want people to invest in long-term outcomes, you have to prove — repeatedly — that the payoff is real. Every broken promise is a signal that says: eat the marshmallow now.
Mischel spent 50 years studying delayed gratification. The popular version of his story says willpower is destiny. The actual research says something far more hopeful: the ability to wait is a skill, shaped by strategy and environment, and you can get better at it starting today.
That’s the real marshmallow test. And most of us are still learning how to pass it.