The marshmallow test: Delayed gratification isn't just a matter of willpower

© 2018 Gwen Dewar, Ph.D., all rights reserved

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Sometimes the smart thing is to reject an immediate reward in order to wait for something better. But this isn’t always the case, and delayed gratification isn’t always a matter of willpower.

Studies show that children’s choices depend a lot on our own behavior. When adults appear unreliable – or downright untrustworthy – kids choose instant rewards over future benefits. Here are the details.

If you’ve read about self-control and delayed gratification in children, you’ve probably
heard of the marshmallow test. Sit a child down at a table, offer him
a marshmallow, and make the following promise:

“You can eat this now if you want, but if you wait 15 minutes
until I come back, and I see you haven’t eaten it, I will give you
another one. You’ll end up with two marshmallows."

What do kids do? Some show great powers of delayed gratification,
not touching that marshmallow for the entire 15 minutes. Others give
in to temptation after only a few minutes.

And it seems to matter. When researchers have followed up on the
preschoolers who’d participated in the first marshmallow
experiments of the 1970s, they have found that a child’s
performance on the test was a predictor of many later outcomes.

Kids who’d waited the longest went on to score higher on
scholastic achievement tests. They were also more likely to finish
college and end up with lower body mass indices, or BMIs.

So the marshmallow test has gotten a lot of attention as a measure
of self-control and a predictor of life success.

But is it really? Can we assume that kids who do poorly on the
marshmallow test – and real-world equivalents of the marshmallow
test– are suffering from a special deficit of self-control? Or is
it possible that these seemingly “impulsive" kids are responding
to the cues around them and making smart choices?

Some kids have learned hard lessons about the world. The adults
they know don’t keep promises, and nobody seems to enforce
fairness. When these kids get something nice, they know that somebody
bigger may come along and take it away.

That’s what struck Celeste Kidd in 2012, when she was a student
earning her Ph.D. in Brain and Cognitive Sciences at the University
of Rochester.

She was watching children at a homeless shelter– children who lived in a dog-eat-dog environment, where theft was
common, and adults rarely intervened.

How would these kids behave in a marshmallow test? The answer seemed clear. "All of
these kids would eat the marshmallow right away."

So she designed a clever new version of the marshmallow experiment, and got some astonishing results. If you manipulate a child’s trust in the adult, you radically change his or her performance on the marshmallow test (Kidd et al 2013).

Learning when to wait

The experiment worked this way:

Before introducing any
marshmallows, Kidd and her colleagues had preschoolers work on an art
project. Each child was seated at a table in an “art project room"
where there was a tightly sealed jar of used crayons. A friendly
adult told the child she could use those crayons now, or she could
wait until the adult returned with some nicer, brand-new crayons.

And then one of two things happened:

  • In the reliable condition, the adult returned after a couple
    of minutes with the new crayons.
  • In the unreliable condition, the adult came back
    empty-handed and apologized. “I’m sorry, but I made a mistake. We
    don’t have any other art supplies after all…"

This was repeated a second time with a promise of fancy stickers.
Again, some kids were rewarded for waiting. Other kids waited only to
get an apology that the stickers couldn’t be found.

After this warm-up, the kids were finally offered the marshmallow
and given the choice. Eat one now, or wait and get two later.

And the results were remarkable.

Children in the reliable condition – who had previously received the promised rewards – waited four times as long their counterparts did.

Moreover, kids in the reliable condition were more likely to wait
the full 15 minutes. Nine of the 14 children in the reliable
condition waited the full 15 minutes, but only 1 of the 14 kids in
the unreliable condition did so.

As coauthor Richard Aslin notes, these are dramatic differences
for an experiment of this kind. Usually when researchers report
they’ve found an effect, the effect is statistically significant,
but rather small. Here we have a quite a big difference – and one
resulting from a brief intervention.

What must things be like for
children who are exposed to unreliable conditions day after day? At
home or elsewhere?

As Kidd and her colleagues noted, children must be experiencing
radically different views of the world depending on their home life. A child living with parents who “reliably promise and
deliver small motivational treats" is going to have reason to wait
for her marshmallow. But for a child “accustomed to stolen
possessions and broken promises, the only guaranteed treats are the
ones you’ve already swallowed."

But it doesn’t end there.

Kidd’s experiment shows us that children adjust their strategies based on their direct experiences with adults. What about indirect experiences? Might children learn by observing how adults treat other people?

An experiment in dishonesty

Maybe kids don’t have to wait for an adult to let them down
personally. To lose faith – and give up on long-term rewards –
maybe it’s enough to catch the adult lying to someone else.

That was the guiding hypothesis of Laura Michaelson and Yuko
Manakata. So they conducted their own marshmallow experiment on preschoolers in Colorado, this time replacing promises of art supplies and stickers
with an opportunity to observe an adult behaving dishonestly towards another person (Michaelson and Manakata 2016).

It went like this.

Each participating preschooler began the experiment with a
friendly adult – an artist – seated at a table with some modeling
clay. The two of them created clay sculptures together while a second
adult watched with interest.

Then, when the artist had completed a sculpture of a bird, she
left the room for a minute. And what happened next varied by group

  • Kids randomly assigned to the trustworthy condition saw the adult
    observer accidentally damage the artist’s sculpture. When the
    artist returned and asked for an explanation, the observer confessed
    and apologized.
  • Kids randomly assigned to the untrustworthy condition saw the
    adult observer break the sculpture on purpose. Then, when the artist
    returned, the observer lied to the artist, saying “No, I didn’t
    break your bird. I don’t know how it got broken."

Thus, half the children in this experiment witnessed an adult misbehave
and lie to another person. Would these observations have an impact on
their willingness to delay gratification?

To answer this question, the researchers had the adult observer administer the marshmallow test. The adult observer gave kids the standard choice: Eat one marshmallow now, or
wait and receive two marshmallows later.
And children's responses depended on
what they had seen the adult do earlier.

Children who’d previously observed the adult behaving honestly were much more inclined to delay gratification. They waited three times longer than the kids who’d
seen the adult misbehave and tell a lie.

So preschoolers don't merely remember and respond to our broken promises. They are also capable of observing our bad behavior toward third
parties and inferring, this person can’t be trusted. I’d better
cut my losses, and go for whatever immediate rewards I can secure
right now.

To be sure, there are other factors. It isn't just our personal behavior that influences a child's willingness to wait.

Delayed gratification also appears to depend on the development of brain structures in the frontal cortex — structures that help us weigh benefits, predict outcomes, and override our impulses (Achterberg et al 2016).

And research in China suggests that kids vary in their willingness to wait as a function of their general outlook on humanity: Kids who express more trust toward people overall tend to wait longer in delayed gratification tests (Ma et al 2018).

But the implications are clear. Delayed gratification is only partly a question of willpower. It's also heavily dependent on a child's environment, and we adults play a crucial role in shaping that environment.

More reading

We can reinforce delayed gratification by behaving in ways that are reliable and trustworthy. What else can we do to help children develop self-control? See these evidence based tips.

References: Delayed gratification and the marshmallow test

Achterberg M, Peper JS, van
Duijvenvoorde AC, Mandl RC, Crone EA.
Frontostriatal White
Matter Integrity Predicts Development of Delay of Gratification: A
Longitudinal Study. J Neurosci. 36(6):1954-61.

Kidd C, Palmeri H, Aslin RN.
2013. Rational snacking: young children's decision-making on the
marshmallow task is moderated by beliefs about environmental
reliability. Cognition. 126(1):109-14.

Ma F, Chen B, Xu F, Lee K, Heyman GD. 2018. Generalized trust predicts young children's willingness to delay gratification. J Exp Child Psychol. 169:118-125.

Michaelson LE and Munakata Y. 2016. .Trust matters: Seeing how an
adult treats another person influences preschoolers' willingness to
delay gratification. Dev Sci. 19(6):1011-1019.

Portions of this article appeared in a previous publication, "Kids fail the marshmallow test when adults are unreliable," written by the same author for BabyCenter in 2012.

title image of waiting toddler by Eduardo Merille /flickr

Original Article