In behavioral sciences, one of our most excellent tools is pattern recognition. We then use patterns of current behavior to make predictions about future behavior. On the other hand, perhaps the most significant thing science does is correct itself when new information shows that an old conclusion is wrong, as in the case of the Marshmallow Test.
With research initially published more than half a century ago, this little experiment was once thought to be an excellent way to predict a person’s success as an adult, and the test could be performed. Conclusions were drawn before the individual was even old enough to start school.
How The Test Works
Plop a four-year-old child in a chair at a table. Show them a marshmallow and explain the rule. If they can sit for 5 minutes without eating the marshmallow, they can have a second one. Leave the room for the promised period, and then return to see whether they’ve devoured the small treat.
For the child, it’s a conundrum. He can have a small or slightly bigger treat now if he can wait five minutes. Since he’s four, he doesn’t really know how long five minutes is, but he knows that if he can be patient and deprive himself for some time, he can have more treats.
What Researchers Thought It Would Predict
This is a skill we use as adults, although in a far more abstract way that we might not even recognize. For example, you could buy yourself a small treat with this week’s paycheck- that new purse, fancy coffees, or a night out- or save that money and use it towards something larger later.
However, psychologists thought the test could predict a more overarching trait: willpower. Willpower isn’t just denying yourself a night at the movies to save for a down payment on a house, it’s also denying yourself a night of partying so that you can make it to work in the morning, and choosing an evening of studying over an evening of video gaming.
Adult success relies heavily on choices like these, and researchers thought that the Marshmallow Test, at age four, would indicate a child’s future ability to make them responsibly.
Spoiler: It Doesn’t
Numerous criticisms of the Marshmallow Test over the years and multiple studies have challenged the premise, but the latest one is particularly damaging. Published in Child Development, this study followed children from age 4 1/2 (54 months) into their mid-twenties and found no real correlation. Their conclusion:
“Using a preregistered analysis, Marshmallow Test performance was not strongly predictive of adult achievement, health, or behavior…No clear pattern of moderation was detected between delay of gratification and either socioeconomic status or sex. Results indicate that Marshmallow Test performance does not reliably predict adult outcomes.”
No Link Between Marshmallow Urgency & Adult Behavior
This isn’t the first study to find no correlation. The original study has been criticized for factors including that all the children originally tested were taken from the Stanford Preschool class, and the sample size of only 90 children.
No researcher has been able to replicate the outcome. However, an effort in 2018 using a larger sample group (900 participants) across a wider variety of socioeconomic backgrounds did find a smaller correlation. However, according to Medium, the correlation was attributable not to lack of willpower but to another factor: socioeconomics.
Kids from poorer households are less able to wait for a marshmallow and more likely to have poorer test scores later in life. Who could have guessed?
What About Other Predictions?
The original Marshmallow Test also purported to show a link between the ability to delay gratification and BMI later in life, and researchers have suggested a link between this exhibition of self-control and behavioral problems in children.
Again, nope.
According to Big Think, Tyler Watts, the lead author in the 2018 study, cited the lack of behavioral link as one of the most unexpected outcomes. He said:
“We found virtually no correlation between performance on the marshmallow test and a host of adolescent behavioral outcomes. I thought that this was the most surprising finding of the paper.”
The new study found only a “modest” association between performance on the Marshmallow Test and BMI.
What Do We Take From This?
So many factors go into children’s success as they grow into adults.
For instance, the 2018 study noticed a link between later performance and whether or not the child’s mother held a college degree. Socioeconomic factors have repeatedly been suggested as a more likely contributor.
The clearest takeaway from this latest study is that if your child isn’t showing signs of great self-control and restraint at age four, it doesn’t mean he’s doomed to a lack of success as an adult. There are years yet to practice this skill, and other factors, like access to education and nutrition, are likely to be much more critical.