Did the marshmallow test prove anything at all?

Back in the Dark Ages when I was "doing" psychology as an extra in my biology/English literature degree, tests that had used children as guinea pigs were popular.  And they all seemed to be based on choices in diet.  And then came the marshmallow test, with a video that was fun to watch.  These kids were shut one at a time in a room with a marshmallow set temptingly before them.  They were told that if they could wait 15 minutes before eating it, they were rewarded with a second marshmallow.

It was an exercise in delaying self-gratification in order to reap profit.  The kids who passed the test were supposed to be brighter, get better academic scores and so forth and so on.  We saw the sense in it, because students all around us were playing instead of studying, getting drunk instead of passing papers.  And, as I said, the video was fun to watch.

But now, according to The Smithsonian, the experimental results depended on socioeconomic status:

If you give a kid a marshmallow, she’s going to ask for a graham cracker. And maybe some milk. Eventually, she’ll want another marshmallow. (Or so the popular children’s book goes.) But if you ask a kid to wait 15 minutes before eating that marshmallow, promising a second if she holds out, she’s going to have a hard time complying.

This dilemma, commonly known as the marshmallow test, has dominated research on children’s willpower since 1990, when Stanford psychologist Walter Mischel and his colleagues published their groundbreaking study on the topic. Overall, they found that those who stop themselves from eating the first marshmallow in order to obtain the second ostensibly exhibit better self-control, a characteristic they linked with later academic and career success.

But according to a new study published in Psychological Science, the marshmallow test is not as decisive as previous research suggests. Instead, results vary based on background factors including socioeconomic status, home environment, and early cognitive ability.

During the 1960s and ’70s, Mischel and his colleagues conducted the marshmallow test on about 90 children enrolled in a local Stanford preschool. Decades later, the team revisited their test subjects to examine the correlation between an early ability to delay gratification (as represented by holding out for the second marshmallow) and later success. As Quartz’s Sarah Todd reports, the positive outcomes exhibited by those who resisted temptation included higher SAT scores and lower body mass index.

The new study, led by New York University’s Tyler Watts and the University of California-Irvine’s Greg Duncan and Haonan Quan, features a revamped version of the original test. Researchers increased the sample size to more than 900 children and included a more diverse array of individuals with a range of ethnicities, income and education levels. They also analyzed results while considering background factors.

“Our results show that once background characteristics of the child and their environment are taken into account, differences in the ability to delay gratification do not necessarily translate into meaningful differences later in life,” Watts tells The Guardian’s Richard Adams. “So, if you looked at our results, you probably would decide that you should not put too much stock in a child’s ability to delay at an early age.”

Amongst participants whose mothers had college degrees, high standardized test scores and reports of good behavior were not significantly associated with whether one held out for the second marshmallow. The same proved true for children whose mothers did not have a college education, at least once household income and home environment were factored into the equation.

Instead, the study suggests that children’s ability to wait for the second marshmallow is shaped by their social and economic background, The Atlantic’s Jessica McCrory Calarco reports, which in turn shapes their chances of long-term success. Those who hold out for the second marshmallow may come from more affluent households, and their future success is based on this economic advantage rather than sheer willpower.

The latest study also hints at why children from lower socioeconomic backgrounds may be quicker to eat that first marshmallow. As Calarco writes:

“For them, daily life holds fewer guarantees: There might be food in the pantry today, but there might not be tomorrow, so there is a risk that comes with waiting. … Meanwhile, for kids who come from households headed by parents who are better educated and earn more money, it’s typically easier to delay gratification: Experience tends to tell them that adults have the resources and financial stability to keep the pantry well stocked.”

Makes sense to me.