The extent to which you believe you will succeed or fail at a task affects the resources the brain brings to bear on the problem. If you think you can do it, the brain shows greater activity than if you don't think you can do it.
And when people who thought themselves either good or bad were faced with different scenarios, people who thought they were good at something had highest brain activity when they had a chance at a big gain, and people who thought they were bad at it had highest brain activity when they stood a chance of a big loss. (Big, in this case, was $5 compared to $1 for college student test subjects.
If it were possible to make oneself believe that one is good at something, one might well become better at it. I guess that's the point of Stuart Smalley's affirmations. If you think you can, you'll try harder, and maybe you'll succeed.
I wonder if affirmations work. That is, I wonder if telling yourself you're good enough at something does change the brain activity when you get to the actual task? People (okay, college students) weren't good at knowing how good they really were, which fits other research. If you really do think you're bad at it, can you lie to yourself and convince yourself that you are good at it? Maybe if you're real gullible, since you know what a liar you are.
The people doing the research are "working toward the development of implanted neural prosthetic devices that would serve as an interface between severely paralyzed individuals' brain signals and artificial limbs -- allowing their planned actions to control the limbs' movements," which is the coolest thing I've heard in months.