The Stanford marshmallow experiment was a study on delayed gratification in 1970 led by psychologist Walter Mischel, a professor at Stanford University.[1] 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,[2] educational attainment,[3]body mass index (BMI),[4] and other life measures.[5] 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.[6][7] The predictive power of the marshmallow test was challenged in a 2020 study.[8][9] Work done in 2018 and 2024 found that the Marshmallow Test "does not reliably predict adult functioning".[10]
^Mischel, Walter; Ebbesen, Ebbe B. (1970). "Attention in delay of gratification". Journal of Personality and Social Psychology. 16 (2): 329–337. doi:10.1037/h0029815. S2CID53464175.