Is there a correlation between self-discipline/delayed gratification and success?

Psychologists (Walter Mischel and others) wondered whether a person's ability to delay gratification --an indication of self-discipline--gave people better life outcomes.  So they devised experiment in which a child was seated in front of a plate with a food treat, and told that if he or she didn't eat the treat until the experimenter returned after a short time, they'd get two treats.

Predictably, some kids ate the single treat and others held out for the delayed reward. 

Mischel then followed the participants for a number of years afterwards.  And he found--hold on to your hats--that there was a strong correlation between self-discipline/impulse control and a large number of other success factors: SAT scores, educational attainment, fitness (measured by body mass index) and several other life measures.

So kids who have more self-control tend to be more successful in life than those who don't?  Wow, who could've predicted that?

What the experiments didn't investigate was how some kids learned that delaying gratification could have benefits.  Were they taught by parents, did they learn by watching successful parents, or was it a genetic trait?  The answers would seem to have a huge impact on the future of the country.

Of course successful parents are far more likely to understand the benefits of working hard now to achieve a valuable goal later--delayed gratification, self-control.  It's worth asking whether parents with problem kids both recognize the connection and teach it to their kids.  Intuitively it would seem that a substantial fraction of parents don't recognize this connection.

Kinda' like all parents should teach their kids not to steal or shoot people for Air Jordans.  Unfortunately far too many parents don't seem to make the connection.

Hat tip to Oregon Muse at Ace of Spades.