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. For example, when adults appear unreliable – or downright untrustworthy – kids choose instant rewards over future benefits. And children show an increased willingness to wait if they believe their peers will do the same. 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 the kid 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 within seconds. 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. So the marshmallow tells us which kids possess the willpower needed for lifetime success. But does 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 back 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? As Kidd notes in a university press release, 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. The experiment went like this. A child is seated at a table in “art project room” where there is a tightly-sealed jar of used crayons, and a friendly adult presents the child with a choice: Either use these crayons now, or wait until the adult returns with some nicer, brand-new crayons. Next, 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. And then — finally — kids were offered the marshmallow and given the choice. Eat one now, or wait and get two later. The results? Children varied in their responses, and adult reliability made a big difference. 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 has remarked, 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 dramatic 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. Each participating preschooler began the experiment the same way: The child was seated at a table with some modeling clay, accompanied by a friendly adult. The two of them created clay sculptures together while a second adult watched with interest. Then, when the adult artist had completed a sculpture of a bird, she left the room for a minute. And what happened next varied by group assignment. 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 seen 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. And research suggests that kids vary in their willingness to wait as a function of their general outlook on humanity: Children who express more trust toward people overall tend to wait longer.