"A gazillion-dollar brain scanner doesn’t hold more predictive power than one marshmallow.”

I came across a great political cartoon published in the magazine, The New Yorker, a few years ago:

"You can eat the one marshmallow right now, or, if you wait fifteen minutes,
I'll give you two marshmallows and swear you in as President of the United States."

Pretty funny, right?  If the individual in the cartoon can refrain from eating the marshmallow, his reward is a second marshmallow and becoming President of the United States! 

I've posted a few times on the infamous "Stanford marshmallow experiment" (see, for example, "What do I know of man's destiny? I could tell you more about radishes.").  Just to jog your memory, this was the test of delayed gratification in which children were given the option of eating one marshmallow now, or sitting alone with the marshmallow for a few minutes and getting a second marshmallow if they didn't eat the first one.  In other words, exactly like the cartoon above. 

 

There are numerous videos on the Internet that show the lengths that some of these children would go to in order to keep themselves from eating the marshmallow.  Supposedly, those children who were able to refrain from eating the first marshmallow (and get a second marshmallow to eat as a reward) had better long-term life outcomes, as measured by college SAT scores, educational attainment, body mass index, and job salary. 

The American scientist Robert Sapolsky had this to say about the original marshmallow experiment, published by Stanford psychologist Walter Mischel:

“Mischel’s next step made his studies iconic — he tracked the kids forward, seeing if marshmallow wait time predicted anything about their adulthoods.  Five-year-old champs at marshmallow patience averaged higher SAT scores in high school (compared with those who couldn’t wait).  Forty years post-marshmallow, they excelled at frontal function, had more PFC [Prefrontal cortex] activation during a frontal task, and had lower BMIs. A gazillion-dollar brain scanner doesn’t hold more predictive power than one marshmallow.”  

  

Incidentally, a much larger study (with 10x the number of subjects) was performed later, and the results weren't quite as impressive.  In the repeat study, these associations between delayed gratification and long-term life outcomes were not nearly as significant, with socioeconomic background playing a much greater role in determining success.