The Marshmallow Test is a psychological experiment designed to study self-control and delayed gratification in children. In the test, a child is given a choice: they can eat one marshmallow immediately or wait a short period to receive two marshmallows later. The experiment measures how long the child can resist the temptation of the immediate reward. Conducted in the late 1960s by psychologist Walter Mischel, the test has been influential in understanding the relationship between self-control and future success. Follow-up studies suggested that children who waited longer tended to have better life outcomes, including higher academic achievement and healthier lifestyles.