Calling Bullshit: The Art of Skepticism in a Data-Driven World

by Carl T. Bergstrom

One of the hallmark discoveries of social psychology is the role that delayed gratification plays in a successful life. At the heart of delayed gratification theory is an experiment known as the marshmallow test. A four-year-old is presented with alternative rewards: one marshmallow or two marshmallows. He is told that he can have a single marshmallow anytime—but if he can wait for a while, he can have two marshmallows. The experimenter then leaves the room and measures the amount of time until the child says screw it, and takes the single marshmallow. (After fifteen minutes of open-ended waiting, a child who has not yet given up receives the two-marshmallow reward. But seriously—do you remember how long fifteen minutes seemed at that age?) A number of studies have shown that children who can wait longer at age four have higher SAT scores in high school, and are rated by their parents as better-adjusted during adolescence. The authors of the original studies were careful to explain that their results demonstrated correlation: Delayed gratification is predictive of later academic success and emotional well-being. They did not demonstrate causation: The ability to delay gratification does not necessarily cause later success and well-being.*6 But as these results filtered through the popular press, the line between correlation and causation became blurred. The results of the marshmallow test and other related studies were reported as evidence that ability to delay gratificati...