One word of caution - I try NOT to tell my DC they are "smart." I try to praise them for hard work, doing their best, and staying focused.
I think every parent needs to assess the right approach here for their child.
Like you, I'm convinced that much of personality exists as hard-wired circuitry in the brain. This week I've been watching DW take on a new project which involves a skill she's only barely begun to acquire, and as she's making mistakes she's muttering a steady stream of variations of the theme, "I suck." Aha. So that's where DD gets it.
I've found myself giving both DD and DW variations of the same pep talk this week: You're smart, and you learn quickly. Mistakes are normal, and just part of the learning process. The thing you're trying to do now is a skill that takes practice and repetition. It'll get easier the more you do this. Etc.
In both of their cases, I believe they NEED that message about their intelligence in order to shore up their confidence against the weight of their natural self-doubts. Other results may vary.
