If a 4-year-old passes the marshmallow test—resisting the urge to immediately eat a marshmallow for the promise of a second one later—then they are destined for academic success. At least that’s what many parents think, based on a famous psychology study published in 1990. But a new version of the study, which looked at a larger and more diverse group of children, is calling the original findings into question, according to The Atlantic. Researchers found that the marshmallow test wasn’t very useful in predicting a child’s future academic success at age 15, once social and economic background were taken into account. The findings, reported in Psychological Science, hold an important lesson for parents: Don’t fret if your child fails the marshmallow test.