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The Stanford marshmallow experiment (wiki) refers to a series of studies on delayed gratification in the late 1960s and early 1970s led by psychologist Walter Mischel, then a professor at Stanford University. In these studies, a child was offered a choice between one small reward (sometimes a marshmallow, but often a cookie or a pretzel, etc.) provided immediately or two small rewards if he or she waited until the experimenter returned (after an absence of approximately 15 minutes). In follow-up studies, the researchers found that children who were able to wait longer for the preferred rewards tended to have better life outcomes, as measured by SAT scores, educational attainment, body mass index (BMI)  and other life measures.  However, recent work calls into question whether self-control, as opposed to strategic reasoning, determines children's behaviour.
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<a href="https://en.wikipedia.org/wiki/Stanford_marshmallow_experiment">https://en.wikipedia.org/wiki/Stanford_marshmallow_experiment</a>
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