Infant expectations of instant or delayed gratification.

Choices between immediate gratification and long-term (but larger) gains are prevalent in human life, which is why the decision-making processes to delay gratification have been studied extensively throughout different developmental ages. Children's delay-of-gratification behaviors have been examined in the well-known "marshmallow test," in which 3- to 5-year-olds are given a marshmallow and told by an experimenter that they can eat it immediately or wait for an unspecified duration of time (which can be capped at 15 min) until the experimenter returns so that they can receive another marshmallow. Children's wait time has been viewed as a good indicator of their later development. Here we show that a group of 22-month-old infants (N = 32) already held expectations about others' choices in a violation-of-expectation looking-time task modeled after the marshmallow test. The infants expected an agent to defer gratification based on a speaker's promise of the second marshmallow available in the future, but to eat the currently attainable marshmallow when the speaker made no such promise. Our findings indicate an early-emerging understanding of others' choices of delayed or instant gratification and shed new light on the development of delay-of-gratification behaviors.