[Stanford professor of psychology Carol Dweck] says people who hold a “fixed” theory [of IQ] are mainly concerned with how smart they are (or are perceived to be). They prefer tasks they can already do well and they tend to avoid tasks on which they may make mistakes and jeopardize their “smart” image.
By contrast, Dr. Dweck says, people who believe in an “expandable” or “growth” theory of intelligence thrive on challenging themselves to increase their abilities, even if they fail at first.Reference: Mindset: It's Really a Lot More Than a Head Game.
I think words like expandable and growth are truly good ones to characterize our intelligence and capabilities in general. We seem to under-utilize the talent we have, so anything that encourages us to tap more of it to serve some well-meaning purpose is good. But as Forbes contributor Rodger Dean Duncan himself points out, such an outside-the-box view of IQ does not necessarily mean we can do anything, and be anything, we want, just because we believe we can. Rather, the fact that we believe we can undoubtedly moves us to do more and be more than otherwise.