(25 boys and 25 girls) from the Bing Nursery School at Stanford University. They ranged in age from 3 years 6 months to 5 years 6 months. The mean age was 4 years 6 months. Six subjects were eliminated because they failed to comprehend the instructions given by the experimenters. Experiment 1 procedures The procedures were conducted by one male and one female experimenter. During the test conditions the male experimenter conducted his session with 3 male and 2 female participants, while the female experimenter conducted her session with 3 female and 2 male participants. The small room where the tests were conducted contained a table equipped with a barrier between the experimenter and the child. On the table, behind the barrier, was a slinky toy along with an opaque cake tin that held a small marshmallow and pretzel stick. Next to the table equipped with the barrier there was another table that contained a box of battery- and hand-operated toys, which were visible to the child. Against one wall of the small room there was a chair, another table, and a desk bell. In experiment 1 the children were tested under the conditions of (1) waiting for delayed reward with an external distractor (toy), (2) waiting for delayed reward with an internal distractor (ideation), (3) waiting for a delayed reward (no distractor), (4) external distractor (toy) without delay-of-reward waiting contingency, and (5) internal distractor (ideation) without delay of reward contingency. Experiment 2 participants The participants consisted of 32 children from the Bing Nursery School of Stanford University. They ranged in age from 3 years 9 months to 5 years 3 months. The mean age was 4 years and 9 months. Six of the subjects were eliminated from the study because they failed to comprehend the instructions or because they ate one of the reward objects while waiting for the experimenter. Experiment 2 procedures Experiment 2 focused on how the substantive content of cognitions can affect subsequent delay behavior. The conditions in Experiment 2 were the same as in Experiment 1, with the exception that after the three comprehension questions were asked of the children the experimenter suggested ideas to think about while they were waiting. These suggestions are referred to as "think food rewards" instructions in the study. They were intended to induce in the subject various types of ideation during the delay-of-gratification period. Experiment 3 participants The participants