[age_bronze]

I don't agree with all the "growth" and "fixed" categorization. Intelligence is fixed, that's pretty much a fact (see all research about IQ etc.). What isn't fixed is your state and knowledge in the process of solving a problem. It has nothing to do with intelligence.

This is the equivalent of talking about cars engines, and how some can get to higher speed than others, when in the end of the day you can probably reach your destination even with an old car engine, that can only drive and accelerate relatively slowly. It didn't magically improve/grow so you can reach your destination. You reach it because you kept the car moving.