“The Marshmallow Test does not reliably predict adult functioning”

We’ve all likely heard about the Marshmallow Test. Kids are given an option of a marshmallow now, or more marshmallows later. And, supposedly, the kids who resist eating the marshmallow now do better in life. Delayed gratification is, we were told, a key indicator of various success measures later in life. I was never totally convinced about this to be honest. And it appears to have now been debunked:

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.