Those who ate the marshmallow before the designated time would not receive a second one.
The most significant aspect of the research was the correlation between being able to wait long enough to earn the second marshmallow and a large variety of indicators for success in academic, personal, and business life.
A variety of followup studies have expanded the range of correlations event further. Tanya Schlam at the University of Wisconsin School of Medicine and Public Health showed a correlation between body weight and success in the marshmallow test. That study was described, in non-scientific terms for the popular audience, in the online magazine Slate in August 2012.
Recent versions of the study involves multitasking and the ability to maintain focus. These have been conducted variously by Larry Rosen at California State University, James Kraushaar and David Novak at the University of Vermont, David Meyer at the University of Michigan, Russell Poldrack at the University of Texas, and Reynol Junco at Harvard.
These versions examine whether students could refrain from checking their smartphones, tablets, or laptops while studying. An informal summary appeared in Slate in May 2013.
Another variation studied environmental variations, particularly whether children had experienced reliable or unreliable promises from authorities. For the purposes of the study, this translated to whether the children believed that they would received the advertised reward. Summarized in Slate in October 2012, the researchers who created this version of the study concluded that unstable home factors would impede academic achievement.
New variants of the marshmallow experiment continue to appear, both in the serious literature, and in popular summaries. In all of them, continued correlations hold to SAT and ACT scores, grade point averages, graduation rates from both high school and college, as well as non-academic metrics like income or divorce rate.
[Andrew Smith is a German teacher at Pioneer High School.]
