President Obama's recent reference to the marshmallow test and its predictive ability and importance got me to thinking about the work, which the media has dubbed the 'marshmallow test' and which was a rather simple, elegant experiment by Walter Mischel and colleagues at Stanford in the late 1960s that sought to illuminate the processes that underpin self-control or willpower. The delay-of-gratification laboratory experiment they developed was straightforward. A four-year-old child was placed in a room with a marshmallow was told by the experimenter as he left the room that if he didn't eat the marshmallow, he would get two marshmallows when the experimenter returned. There were five hundred original participants at the Bing Nursery School at Stanford. While this was not originally designed as a longitudinal experiment, it has become one with long term follow-up and assessment of approximately 33% of the original participants.
The predictive validity of the ability to delay gratification in preschoolers is demonstrated in a number of studies. The number of seconds that preschoolers waited for the delayed reward predicted significantly higher SAT scores as well as better coping in adolescence (Shoda and Mischel). Ayduk et.al. found that the delayed gratification also predicted later outcomes such as higher educational achievement better coping with stress, less cocaine or crack usage, and better self-esteem. He also found that early delay ability tended to buffer against dispositional vulnerabilities such as borderline personality disorder in a later study. Early delay ability also predicted less verbal and physical aggression, less bullying behavior, and higher self-esteem.
Since the desirability of early delay is so clear, Mischel had devised a number of cognitive strategies to assist in resisting the immediate temptation. One is to redirect attention or alter the cognitive representation of the desired object. He has suggested looking away from the object. Another method is to reframe the situation from something desirable to something neutral. The example here would be to think of the marshmallow as a piece of cotton rather than a sweet which should also reduce its strong and pleasurable taste appeal.
The next step is to explore the underlying neural circuits and compare those with early control to those with early lack of control. These will be explored by functional MRI and diffusion tensor imaging (DTI) in the candidate circuits, especially the frontostriatal (where less myelination and orientation regularity are suspected) and the frontoparietal, which is needed for cognitive control especially where incentives are involved.
This research is enormously important to large numbers of individuals because it has implications for their mental and physical health as well as their social, marital, vocational and economic well-being. These are just the type of issues that are being evaluated now because the original participants are starting the middle portion of their lives.