In 2017 my family and I moved from Boulder, Colo., to live in Kyoto, Japan. My kids immediately noticed many cultural differences. Japanese homes typically do not have central heating, for one. We arrived during an unusually cold February, so my older child would curl up under the kotatsu—a low dining table with a heater affixed underneath—to get warm. After enrolling in the neighborhood elementary school, my kids saw how their peers cleaned classrooms and served food, unlike in the U.S., where specialized workers handle each task.
One of their most memorable lessons occurred during their first school lunch. They lined up with their classmates to be served, carried their lunch tray to their seat and started eating. The other students quickly began shaking their head and waving their hands. My children didn’t speak Japanese, but the message was clear; they stopped eating. After every student in the classroom sat down with their food, the students called out in unison, “Itadakimasu”—literally “I humbly receive” and akin to “bon appétit.” Then they began eating together. The next day, my kids waited to eat along with all their classmates.
When my children described this situation, it got me thinking. Many studies have looked at the ability to delay a snack as a measure of self-control—and found that such delayed gratification foretells a brighter future. Was it possible that children in Japan had a special advantage?
The incident inspired me, as a psychologist, to reexamine a classic experiment involving delayed gratification for a food reward. What I learned would shift how I think about self-control, individual differences, human development, equity in science and my heritage.
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The classic marshmallow test, invented by the late psychologist Walter Mischel, involves presenting a child with one marshmallow and explaining that they can have it now or they can have two later if they wait until the marshmallow giver returns. Children sit alone in a room with the tempting treat. Psychologists have generally viewed the length of time kids resist the sweet as a measure of their self-control: how effectively they can inhibit impulsive behaviors and work toward longer-term goals. Some studies have found that better performance on that marshmallow test in childhood predicts better outcomes in school, relationships and health later in life.
Together with Satoru Saito of Kyoto University and Kaichi Yanaoka of the University of Tokyo, my research team revisited this test with a few twists. We worked with 144 children in both the U.S. and Japan. We first ensured that all of these four- and five-year-olds had eaten marshmallows before. We asked parents how often their children waited to eat until others were served and how well their children could suppress impulsive behaviors.
Then the kids faced the classic test: Did they want one marshmallow now or two later? Most children in the U.S. waited less than four minutes before tasting the one marshmallow. Most children in Japan waited for two marshmallows for the maximum possible time—15 minutes!
If we had stopped there, we might have simply concluded that Japanese kids have better self-control. But we conducted another test. We presented children with a wrapped gift and told them that they could open it now or they could have two gifts if they waited. The pattern flipped. Most children in Japan waited less than five minutes before unwrapping the gift, while most children in the U.S. waited the maximum 15 minutes or close to it.
What was going on? It seems that with repeated experiences delaying gratification, children can develop habits that make it easier to wait in the future. According to the reports from their parents, the Japanese children had stronger habits of waiting to eat than the U.S. children. The stronger these habits, the longer the children waited for two marshmallows. But when it comes to opening gifts, children in the U.S. likely experience waiting more consistently. Birthday presents can sit on a table, unopened, until the end of a party. Christmas presents may sit under a tree for days before they can be unwrapped on December 25. In Japan, people give gifts year-round on simple occasions that do not involve traditions of waiting.
Not only did children wait longer when our test of delaying gratification aligned with their cultural experiences, they seemed to rely on different skills. We assessed how sensitive children were to social conventions about how they should behave. The greater their sensitivity, the longer they waited to open the gift in the U.S. and the longer they waited to eat the marshmallow in Japan. How well they could suppress impulsive behaviors no longer mattered.
These findings suggest that delaying gratification isn’t just about self-control. Cultural routines—and how sensitive we are to them—make a difference in how long we wait. These routines can vary not just between cultures but within a culture, based on heritage, socioeconomic status and geographical area. So when a child waits for two marshmallows and goes on to succeed in school and life, this may partially reflect their experiences and habits around delaying gratification. These habits may actually supplement their self-control, helping them delay gratification in ways that serve them well in school and beyond. Children learn how to navigate social situations, attend to elders and tackle chores or homework in culturally specific ways that may help them later—if their habits align with the demands they face.
This research also raises big-picture questions for my field. Our study demonstrates how the results from psychology and other sciences sometimes capture cultural nuances that scientists may not even recognize. If we had conducted our study in just one country or with just one reward, we would have reached very different conclusions. How many other studies of human behavior reflect narrow cultural lenses? For that matter, how often has our research and academic culture privileged just a subset of voices and experiences? Without meaning to do so, we as researchers may be comparing people without considering how cultural norms, years of practice and social scaffolding make a particular task significantly harder or easier for some than others.
Fortunately, we can take steps to address this problem. Centering historically marginalized voices in our science can address research misconceptions and gaps. It can also give us a deeper and more equitable understanding of human behavior.
My family and I are living in the U.S. again. Thanks to this study, we now share knowing looks when it comes to dessert. If my husband suggests getting ice cream—as he often does—I tend to propose we hold off and do something to earn it first. I used to think we just differed in self-control. But my parents immigrated to the U.S. from Japan only a few years before I was born, and they raised my sisters and me in their traditions. Delaying gratification for ice cream doesn’t feel effortful to me. I see now how old habits run deep.
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This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.