But here’s the thing. These prescriptions are unwarranted, because we don’t actually have strong evidence that the ability to delay gratification causes subsequent success. When a research team went back and attempted to replicate the original marshmallow studies with a larger sample size and additional controls, they found only a fraction of the original effect. Moreover, there was a single factor that seemed responsible both for a child’s ability to delay gratification and for success during adolescence: the parents’ socioeconomic status.*7
