Here’s a link to a article that is a follow-up to the famous Marshmallow study of the 1960s. Turns out, you can correlate SAT score and the ability to save for retirement as early as age two! Both require: delayed gratification, self-control, discipline, obedience, etc.
According to Mischel, this view of will power also helps explain why the marshmallow task is such a powerfully predictive test. “If you can deal with hot emotions, then you can study for the S.A.T. instead of watching television,” Mischel says. “And you can save more money for retirement. It’s not just about marshmallows.”