Irwin: Incentives, rewards and expectations

Over 50 years ago, a Stanford psychologist designed and conducted the “Marshmallow Experiment” study on delayed gratification. In it, children were offered an immediate reward (the aforementioned marshmallow) or a larger reward (more marshmallows) if they were willing to wait. Follow-up studies found that those children who could delay gratification had better life outcomes as measured by SAT scores, educational achievement, and body mass index. In other words, they seemed smarter, healthier, and more successful. This study has been repeated, reworked, and cited many times over the years. Other factors — wealth, living environment, etc. — it turns out, have an impact on the predictive power of the experiment.