After reading Carol Dweck's Mindset, I'd be worried about a child focusing on the "smart" label.

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"Kids get so caught up in the moment-to-moment issue of will they look smart or dumb, and it blocks them from thinking about the long term," says Carol Dweck, a psychology professor at Stanford. "[You have to teach them that] they are in charge of their intellectual growth."
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http://www.time.com/time/magazine/article/0,9171,1126743,00.html#ixzz0fFvZ9hXx