Final answer:
The marshmallow experiment involved offering children a choice between an immediate reward or delaying gratification for a bigger reward.
Step-by-step explanation:
In the marshmallow experiment, a preschool child was placed in a room with one marshmallow on the table. They were given the choice to eat the marshmallow right away or wait until the researcher returned to the room to receive two marshmallows as a reward. The study found that children who were able to delay gratification and wait for the bigger reward showed higher levels of self-control and went on to have better outcomes in high school, such as higher SAT scores, positive peer relationships, and fewer behavioral issues.