Cory Doctorow – writing for Locus Mag and using the Stanford marshmallow experiment as an allegory – tears down the inherent flaws of the conservative premise that self-discipline is a determining factor on someone’s chances in life:

On average, the kids who “fail” and eat the marshmallow rather than waiting and doubling their haul were poorer, while the “patient” kids were from wealthier back­grounds. When the “impatient” kids were asked about the thought process that led to their decision to eat the marshmallow rather than holding out for two, they revealed a great deal of future-looking thought…The adults in these kids’ lives had broken their promises many times: Their parents would promise material comforts, from toys to treats, that they were ultimately unable to provide due to economic hardship.

Conversely, those kids who were able to delay their gratification for double the reward came from wealthier homes:

Which means that the “patient” kids weren’t demonstrat­ing “self-control” – rather, their willingness to wait for a second marshmallow reflected a charmed life in which adults came through with the goodies they promised. That same charmed life saw those subjects enrolled in the best schools, backstopped by tutors and college application consultants, significant parental financial contributions to excellent postsecondary education, and smooth entry into the job market.

Self-discipline and delayed gratification are virtues worth developing in all humans. Our planet and future generations depend on it. But it can only be done when people are on equal footing stable enough to allow for that development.