Did Mozart have to practice the piano? Yes, and he did for hours each day. Did Einstein have to memorize the times tables? Of course, for where would we be if he hadn’t?

I must read the Scientific American article, to be sure, but I’m guessing that there is a discussion of the difference between IQ and achievement in the article.
IQ alone does not guarrantee achievement, although the two are correlated in population studies.But those tell us little about the actions of each individual with a given IQ.

And IQ, as much as testing loads onto g (genera ability) does not change significantly. The problem, though, is that sometimes, due to problems getting at g on IQ tests, the scores do not reflect an individual’s general ability. Then if the problems are remediated, you see an increase in IQ. For example, many studies have shown that motor difficulties will lower the IQ score on tests–especially on the performance IQ component–but then the score doesn’t reflect g very well.

Although we know there are differences among individuals when it comes to cognitive abilities, just as there are variations in height, weight, and other continuous traits, ultimately each individual must put forth some effort in order to develop commesurate with that potential.

Should we tell kids they’re smart? I expect that they will figure it out for themselves. But we ought to tell them, over and over again, that brains alone do not get you where you want to go. To do the things in life you want to do, you’ve got to develop patience, persistence, and a good work ethic. And more than tell them this, we ought to demonstrate it in our own lives. Sometimes good stuff comes easily, but not often.