People who have achieved a high level in academia putting a lot of effort into a study that proves that people who achieve highly in academia have a lot of self discipline (i.e. put in a lot of effort).
Clearly they don't have a high level of intelligence as if they did, they would have figured out (having put in a bit more thought and a bit less effort), like you and I, that the educational system is obviously like this.
you can make the argument, that it is good to have empirical evidence of something that is intuitively true, because intuitively true things aren't always intuitively true.
