The Stanford marshmallow experiment was a study on delayed gratification in 1972 led by psychologist Walter Mischel, a professor at Stanford University. In this study, a child was offered a choice between one small but immediate reward, or two small rewards if they waited for a period of time. During this time, the researcher left the child in a room with a single marshmallow for about 15 minutes and then returned. If they did not eat the marshmallow, the reward was either another marshmallow or pretzel stick, depending on the child's preference. In follow-up studies, the researchers found that children who were able to wait longer for the preferred rewards tended to have better life outcomes, as measured by SAT scores, educational attainment, body mass index (BMI), and other life measures. A replication attempt with a sample from a more diverse population, over 10 times larger than the original study, showed only half the effect of the original study. The replication suggested that economic background, rather than willpower, explained the other half. The predictive power of the marshmallow test was challenged in a 2020 study. Original Stanford experiment The first experiment in delayed gratification was conducted by Walter Mischel and Ebbe B. Ebbesen at Stanford University in 1970. The purpose of the study was to understand when the control of delayed gratification, the ability to wait to obtain something that one wants, develops in children. Most of the research conducted during that time was done with delayed rewards in areas such as time perspective and the delay of rewards, resistance to temptation, and psychological disturbances. Not many studies had been conducted in the area of human social behavior. The authors hypothesized that an increased salience of a reward would in turn increase the amount of time children would be able to delay gratification (or wait). Since the rewards were presented in front of them, children were reminded of why they were waiting. The attention on the reward (that was right in front of them) was supposed to make them wait longer (for the larger reward). The children were led into a room, empty of distractions, where a treat of their choice (either two animal cookies or five pretzel sticks) were placed on a table. The researchers let the children know they could eat the treat, but if they waited 15 minutes without giving in to the temptation, they would be