People say a lot of silly things about how belief in the importance of intelligence, true or false, is “dangerous.” Today I read one of the few pieces that actually presents some thought-provoking evidence on this point: Carol Dweck‘s chapter in Why Smart People Can Be So Stupid. In the most interesting experiment, Dweck explains that she and co-authors randomly assigned students to read an article arguing either that intelligence is (a) “fixed”, or (b) “malleable.” What happened?

After they finished the article and wrote about it, students went on to another task, one that was quite challenging…

Compared to the students who were focused on the idea of fixed intelligence, those who had been taught to focus on malleable intelligence now saw their difficulty as reflecting on their effort and were more persistent in their pursuit of task mastery…

Other studies found that:

Teaching students the malleable theory of intelligence not only aided their performance in the face of obstacles on an individual intellectual task, it actually raised their college grade point average and their commitment to school.


[S]tudents who confronted the transition [to junior high] holding a malleable view of intelligence earned higher grades and higher achievement test scores than did their classmates who held the fixed view. This was true even though the two groups of students had entered with equal academic skills (and equal self-esteem).

The punchline, as I read it, is that people try harder if they believe that effort has a bigger payoff. This makes a lot of sense – so far, so good.

But is it helpful to convince people that effort has a bigger payoff than it really does? Yes, they’ll be “more successful” ignoring the cost of effort. But why should we ignore the cost of effort – especially when it has a small return?

Thus, I suspect that students with who believe in malleable intelligence are more likely to go to graduate school despite low test scores. They’ll probably get better grades because of their belief. But better is often not good enough. Belief in malleable intelligence is no free lunch – it could easily lead students to waste years of their lives trying and failing.

Don’t like that example? Here’s another: Know any struggling actors? How many of them should just give up?

Overall, I’m better off with a realistic assessment of the importance of ability and effort. If I thought that working an extra hour per day would make me as successful as Steve Levitt, I’d do it. And if I worked an extra hour per day, I would be more successful. But probably not much more – and there’s a lot more to life than economics.