Students who are told they can get smarter if they train their brains to be stronger, like a muscle, do better in school, a new psychology study shows.

Many people have various theories about the nature of intelligence. Some view it as a fixed trait, while others see intelligence as a quality that can develop and expand.

These ideas have can have a profound effect on the motivation to learn, said researcher Carol Dweck, a child and social psychologist at Stanford University.

"Those who follow a fixed theory are concerned with whether they look smart or dumb. They don't enjoy tasks that are difficult, where if they have a setback they can look dumb," Dweck explained. "Those who think intelligence is something you can cultivate are much more interested in being challenged than in just looking smart. They are much more resilient and persistent, and not as worried about making mistakes."