Let them eat marshmallows! It turns out the famous marshmallow test of willpower – the association between how long preschoolers can resist one marshmallow now for the promise of two later and higher test scores and earnings – did not replicate. Once the sample expanded beyond Stanford’s faculty daycare, and controls for parental social class and child characteristics were included, the effect of delayed gratification was much reduced.
But why did people take such psychological ideas so seriously in the first place?
At the outset, it is important to clarify that the recent replication failure does not tell us that willpower does not “matter.” It tells us specifically that willpower or delayed gratification measured in childhood doesn’t matter to academic attainment independently of parental social class and other factors. But it is the underappreciation of these other factors that led to a popular, yet misleading, narrative tying willpower to desert.
To understand how this began, let’s look at how Walter Mischel, the man behind the marshmallow test, got started in 1960s Stanford. Mischel set a model for today’s bestselling celebrity-psychologists, such as Angela Duckworth, by publishing popular books that combined simple summaries of their research with personal memoirs and how-to guides.