The document discusses the marshmallow experiment which studied children's ability to delay gratification. In the experiment, children were given a marshmallow and told they could eat it, but if they waited without eating it while the researcher stepped away, they would get an extra marshmallow. The experiment showed that children's ability to delay gratification, known as self-control, can be improved through strategies like imagination, distraction, self-talk, exercise, and breaking down complex tasks into smaller steps.