Published: May 3, 2018 By
A girl eats a marshmallow.

How a child鈥檚 social groups behave can significantly influence his or her ability to practice self-control and could have lasting impacts on development of this critical skill, according to a new CU 麻豆影院 study of 100 preschoolers.

Key takeaways
  • Preschoolers who thought their "in-group"听waited to have two marshmallows, instead of eating one immediately, waited significantly longer themselves
  • If they thought their "in-group"听displayed self-control, they later tended to think kids who had self-control were nicer and preferred them as playmates
  • Self-control鈥攁 key predictor of employment, health, and academic success鈥攊s critically shaped by childhood social groups

罢丑别听, published in the journal听Psychological Science, found that when kids between 3 and 5 years old were told that members of their 鈥渋n-group鈥 opted to wait to receive two marshmallows, rather than getting one immediately, they were twice as likely to wait themselves. They also grew to perceive other kids who delayed gratification as 鈥渘icer.鈥

The findings run counter to prevailing assumptions that self-control鈥攁 key predictor of employment, academic success and health in adulthood鈥攊s primarily shaped by neurocognitive or psychological factors. The research suggests that much can be done to cultivate it in children and even adults, the study authors said

鈥淭ypically, self-control has been thought of as a trait that a child has or doesn鈥檛 have,鈥 said lead author Sabine Doebel, a postdoctoral researcher in the Department of Psychology and Neuroscience. 鈥淥urs is the first study to show that group behavior and group norms influence self-control in children.鈥

For the study, Doebel and co-author Yuko Munakata, a psychology professor at CU 麻豆影院鈥檚 Institute of Cognitive Science, recruited 100 Colorado preschoolers and had them complete a variation of the 鈥渕arshmallow test鈥 a classic test of self-control.

While a video camera rolled, each child entered a room where they found a marshmallow and a colored T-shirt. A researcher told the child to put the T-shirt on, showed them pictures of kids wearing the same color and then told them they got to be in that group. They also showed them pictures of kids in different colored shirts, a.k.a. 鈥渢he out group.鈥

The child was offered a choice: They could eat one marshmallow now or wait until the researcher went to get more and receive two. 鈥淢ost children really want that second marshmallow so they say, 鈥業鈥檒l wait,鈥欌 said Doebel.

Child doing the marshmallow test

A child takes the "marshmallow test"鈥攁 classic measure of self-control. (Credit: CU 麻豆影院)

One group was then told that their in-group waited and their out-group didn鈥檛. Another was told their in-group didn鈥檛 wait and out-group did. After the experimenter left the room, the听group that believed their in-group waited tended to wait longer, with half the children waiting as long as 15 minutes.

鈥淚t is extremely hard for kids this age to sit there that long, but just knowing their in-group waited seemed to make it easier,鈥 said Munakata.

In a second experiment, the first test was repeated. Then children were shown photos of other children not affiliated with the in- or out-group and told whether those children waited or didn鈥檛 wait. When asked who they would rather play with the kids whose in-group had waited picked the kids who had waited.

鈥淭his suggests that they were not just copying their group in the moment, but that what their group did actually shaped the way they felt about self-control later,鈥 said Doebel.

Practicing self-control in key developmental years is not only important for safety reasons (resisting the temptation to touch a hot stove or chase a ball into the street, for example), but may also have long-term consequences by strengthening neural connections associated with the skill and making it easier to practice throughout life.

鈥淎 child鈥檚 level of self-control predicts all kinds of important life outcomes, from what they earn to what their health looks like to how likely it is that they will end up in jail,鈥 said Munakata.

The authors stressed that while preschool is an ideal time to do so, it鈥檚 never too late to cultivate self-control. They advise exposing kids to good role models鈥攊n books, shows, and real life鈥攚ho exhibit it and value it. The same holds true for adults. 鈥淪tudies have shown that adults are more likely to lose weight, quit smoking or achieve other goals that require self-control if their friends or friends of friends do,鈥 said Munakata. 鈥淪o choose your friends accordingly.鈥