So argues a new study described in Scientific American.

Several years later I developed a broader theory of what separates the two general classes of learners—helpless versus mastery-oriented. I realized that these different types of students not only explain their failures differently, but they also hold different “theories” of intelligence. The helpless ones believe that intelligence is a fixed trait: you have only a certain amount, and that’s that. I call this a “fixed mind-set.” Mistakes crack their self-confidence because they attribute errors to a lack of ability, which they feel powerless to change. They avoid challenges because challenges make mistakes more likely and looking smart less so. Like Jonathan, such children shun effort in the belief that having to work hard means they are dumb.

The mastery-oriented children, on the other hand, think intelligence is malleable and can be developed through education and hard work. They want to learn above all else. After all, if you believe that you can expand your intellectual skills, you want to do just that. Because slipups stem from a lack of effort, not ability, they can be remedied by more effort. Challenges are energizing rather than intimidating; they offer opportunities to learn. Students with such a growth mind-set, we predicted, were destined for greater academic success and were quite likely to outperform their counterparts.

In one study, they found a correlation between students' views on whether intelligence was more an innate ability or something you could improve if you worked at it and their performance upon entering 7th grade, when the academic load and grading standards increase. Students that tended to think that intelligence was more flexible tended to do better.

Another earlier study found an increase in effective learning in a group in which students were praised for their effort over students who were praised simply for being smart.

The author then suggests that if you want to raise kids who do really well academically, the best course of action is to praise them for the effort they put into school (e.g. time spent working), rather then just praising them for being smart.

Sounds pretty reasonable to me.