New twist on marshmallow test: Kids depend on each other for self control

They described their findings in a recent paper in Psychological Science.

As we previously reported, Mischel’s landmark behavioral study involved 600 kids between the ages of four and six, all culled from Stanford University’s Bing Nursery School. He would give each child a marshmallow and give them the option of eating it immediately if they chose. But if they could wait 15 minutes, they would get a second marshmallow as a reward. Then Mischel would leave the room, and a hidden video camera would tape what happened next.

Some kids just ate the marshmallow right away. Others found a handy distraction: covering their eyes, kicking the desk, or poking at the marshmallow with their fingers. Some smelled it, licked it, or took tiny nibbles around the edges. Roughly one-third of the kids held out long enough to earn a second marshmallow. Several years later, Mischel noticed a strong correlation between the success of some of those kids later in life (better grades, higher self-confidence) and their ability to delay gratification in nursery school. Mischel’s follow-up study confirmed the correlation.

Mischel himself cautioned against over-interpreting the results, emphasizing that children who simply can’t hold out for that second marshmallow are not necessarily doomed to a life of failure. A more nuanced picture was offered by a 2018 study that replicated the marshmallow test with preschoolers. It found the same correlation between later achievement and the ability to resist temptation in preschool, but that correlation was much less significant after the researchers factored in such aspects as family background, home environment, and so forth. 

Attentiveness might be yet another contributing factor. As we reported last year, kindergarten children whose teachers rate them as being highly inattentive tend to earn less in their 30s than classmates who are rated highly “pro-social,” according to a 2019 paper in JAMA Psychiatry. In fact, inattention could prove to be a better predictor of future educational and occupational success than the marshmallow test. A single teacher’s assessment may be sufficient to identify at-risk children.

Still, the ability to delay gratification is definitely a desirable quality. Among other benefits, it helps facilitate cooperation with others. (Mischel’s interest stemmed from his own three-pack-a-day smoking habit; he kept trying, and failing, to quit.) For this latest study, scientists at the Max Planck Institute for Evolutionary Anthropology designed a slightly different version of the marshmallow test to explore the cooperative benefits of self-control.

“For instance, for people to share their food with others—for which they might earn a good reputation or reap long-term reciprocal benefits—they must resist the immediate temptation to eat the food themselves,” the authors wrote. “Likewise, a researcher aiming to contribute to a collaborative project must withstand the urge to watch entertaining videos on the Internet.”

The 200 subjects were all five- and six-year-old children from two distinct cultures: Germany and the Kikuyu tribe of Kenya. The experiments were conducted in a lab in Germany and in local schools in Kenya. Prior to the experiments, the children played a collaborative game of balloon toss as a warm-up exercise.

There were three experimental setups. In the “solo condition,” two children were each given a cookie—an Oreo for the German children, a vanilla cookie for the Kikuyu children—and told that if they could wait to eat it, they would receive another cookie. This is essentially the classic marshmallow test, since the result for both children was not in any way affected by what their partner did. For the “interdependence condition,” both children were given cookies and told that if they both successfully waited to eat it, both would get a second cookie. But if one child couldn’t delay his or her gratification, neither child would receive a second cookie.

Finally, for the “dependence condition,” both children were given a cookie. Each child was told that if they could refrain from eating it, both they and their partner would get a second cookie. However, each child thought that their decision would not be affected by whatever their partner decided. In other words, they thought their partner depended on them, but they did not depend on their partner.

The researchers found that the Kikuyu children were a little more likely to wait it out in general than the German children, which they attribute in part to cultural factors. But in both groups, there were significantly more children who chose to delay gratification in the interdependence condition than in the solo condition—evidence that children begin developing a sense of social obligation to others at a young age. In other words, “children are more willing to delay gratification for cooperative than for individual goals,” the authors wrote. However, there was no clear difference between the solo and dependence conditions. Interdependence is the key.

Nor was this a rational calculation, i.e., weighing the cost of holding out with how much value the second cookie held for the child. If that were the case, the authors suggest, kids would have been less likely to delay gratification in the riskier interdependence scenario. Instead,  “Children may have been motivated to delay gratification because they felt they shouldn’t let their partner down,” said co-author Rebecca Koomen, “and that if they did, their partner would have had the right to hold them accountable.”

“The fact that we obtained these findings even though children could not see or communicate with each other attests to the strong motivational consequences that simply being in a cooperative context has for children from early on in development,” said co-author Sebastian Grueneisen.

DOI: , 2020. 10.1177/0956797619894205  (About DOIs).