How a simple marshmallow can predict your future

A child's ability to delay gratification for 15 minutes pays educational dividends years later, studies find

Mon Nov 02 2009

In the Marshmallow Test, a child can have one treat immediately, or two if he can wait 15 minutes. The ability to wait is called "executive function."




It's called the Marshmallow Test. And some neuroscientists believe it is a critical first step needed to improve schooling.

"It's going to be huge," says Martin Westwell, a neuroscientist at Flinders University in Adelaide, Australia, adding that many studies show it foretells success in life more accurately than how well a child can read or do math.

The Marshmallow Test got its name from an experiment at Stanford University in the 1960s on 4-year-old nursery school pupils. Researchers told children that they could have one thing they really wanted right away a marshmallow, or a candy or a cookie, for example but if they could wait while the researcher left the room and came back about 15 minutes later, they could have two.


Neuroscientists are getting a better understanding of executive function by seeing what is happening biologically inside the brain.

York University professor Stuart Shanker uses electroencephalographs (EEGs) that look at the dorsal and ventral sides of the anterior cingulate cortex (ACC) of the child's brain.

These EEGs show that in children who are not managing anxiety or fear, the ventral part of the ACC is really firing, spurred by the primitive limbic, or reptilian, system of the brain.

In children who are showing strong self-regulation, the dorsal part of the ACC is firing instead, controlling responses from the more primitive part of the brain.

"You can literally see whether children are controlling anxious responses," Shanker says.


It was designed to test self-control. The researchers, led by psychologist Walter Mischel, found only about 30 per cent of more than 600 children tested could hold out.

That's as far as it went until the early 1980s, when Mischel followed up and discovered the children who had been able to wait for two marshmallows were also doing better academically.

Jonah Lehrer, in a recent New Yorker magazine article, reports those children who waited 15 minutes averaged 210 points higher more than 10 per cent on college entrance exams than did those who could wait only 30 seconds.

Collectively, the brain skills needed to wait for marshmallows are known as "executive function" or, more broadly, as "self-regulation." They include inhibiting impulses, sustaining attention, planning, prioritizing, and finding and carrying out strategies to stick to your plan.

In kid-friendly language, it means you can "rise to the challenge."

Here's the really exciting thing: Like math and reading, these skills can be taught and learned. They are not genetic. We can all learn how to get more marshmallows.

Indeed, teachers could learn to teach the ability to self-regulate, says Stuart Shanker, research professor of psychology and philosophy at York University and a leading figure in neuroeducation.

His research on children shows that learning self-regulation is a primary task of newborns. But the later years matter greatly. Shanker is amused when he reads about a 5-year-old who has strong executive function skills. It doesn't mean that child will have them at 6 or 16 or even 66. Those more complex executive function skills must be learned as you age.

When a baby is born, he says, it has a relatively undeveloped brain and primitive emotional circuits fear, rage, love and curiosity but no ability to control them. To do that, he argues, the baby must learn from the higher-level brain of its parent or caregiver, laying down pathways of neural connections through one-on-one stimulus and response between the two. That's what a parent is doing by teaching the baby to calm itself, for example.

"By being regulated, a baby acquires the ability to regulate," Shanker says.

Sometimes, though, that process is interrupted by stress, hunger, environment or the caregiver's inadequate responses. And that creates problems for the child at school, for the schools and, ultimately, for society.

Shanker says perhaps as many as half of North American children have poor self-regulation by the time they get to school, citing a study of nearly 3,600 teachers in the U.S. in 2000. It manifests in high rates of attention-deficit disorder or hyperactivity, among many other problems.

He and others trace some of this to the increase in neurotoxins such as mercury, air pollution and now-banned PCBs passing through the umbilical cords, making some children hypersensitive (and others not sensitive enough) to touch, sound or sight.

That, in turn, interferes with the child's ability to learn self-regulation from a caregiver. Their nerves jangle (or remain numb) at the slightest stimulation. In sheer self-protection, the supersensitive shut down that sense.

Shanker remembers a child at a school in New Zealand where he was doing research who was considered uncontrollable. Did she have a disorder, the teachers wondered. Should she be on drugs?

Shanker talked with her in her classroom. He wasn't getting anywhere. So he asked: "What's going on?" She said: "I can't pay attention to you when the fan's going."

He looked around the room, trying to find the fan. Straining his ears, he could hear a faint whir in a ceiling vent. He turned it off and the child calmed immediately.

"The message to teachers is that they need to be a bit of a scientist too," says Shanker. "What we want teachers to understand is that there's no such thing as a lazy child or a bad child. There's always a biological story. The key is to ask why, why, why?"

Is that realistic for a teacher who has 30 kids in a classroom?

"We don't have a choice," says Shanker. "We have to ask ourselves, `What was the goal of universal education?' ... Realistically, if the goal of education is to help each child maximize potential and we are nowhere close to achieving it, then what do we change?"

For example, Shanker has looked at the phenomenon of children doing well in school only to fall off the cliff, academically, at about 13, a phenomenon evident in high school dropout rates as children hit a more complex environment and don't know how to cope.

"Even if a kid comes into school with poor self-regulation, there's something we can do. And if a kid's got good self-regulation, we can grow it," he says.

He points to the work of the Russian psychologist Lev Vygotsky, who died in 1934. Vygotsky developed tools outlined in the modern book Tools of the Mind by Elena Bodrova and Deborah Leong that children can use to learn in a deliberate fashion.

A simple example is asking a child to hold a drawing of an ear while she's listening to another child read a story. This helps the listening child remember what her goal is.

The old game "Simon Says" is a perfect example of an early-school activity that can help a child improve attention, motor control and control of impulses. So is having toys just far enough away from a small child so the child has to get up and get the toy, play with it and put it back before getting another.

Teaching executive function skills to older students might involve teaching them how their brains work, explicitly teaching them strategies to accomplish their goals (including practice and showing them how), and helping them understand what their goals and motivations are, says Lynn Meltzer, a Massachusetts-based psychologist.

Shanker stresses that learning executive function skills is not the same as complying with someone's orders. Self-regulation comes from within. It is self-directed.

"Compliance is a terrible indicator of success," he says, adding an authoritarian stance at home or at school is a doomed policy. "Zero-tolerance? Are you insane?"

Ideally, says Shanker, it's not only the pupils who have good self-regulation. It's also the teachers, the principals, the community leaders. "Students do well with teachers who self-regulate. And teachers do well with principals who self-regulate."

Zachary Stein, 28, is a PhD candidate in human education and development at Harvard University's graduate school of education and a graduate student of Kurt Fischer, one of the giants of neuroeducation. He has a word of caution about the rage for executive function.

It's not a quick fix that can be taught in isolation from other aspects of neuroscience, such as the need to understand that emotion is a critical part of decision-making and learning, or that part of the way the brain learns is to relearn.

By the way, Stein took a later version of the marshmallow test, involving candies, when he was in first or second grade and living in New Jersey.

He withstood temptation. How? By dancing on his chair and eventually pushing tiles out of the test room ceiling to distract himself.

"Basically, I misbehaved," he says, chuckling.