What does Arnold mean by “the power of expectations”?

The power of expectations is the lengths to which one will go to achieve what we're expected to achieve.... the things others expect of us that we want to live up to. When Junior went to school on the reservation, he accomplished nothing.... because no one expected him to. At Rearden, expectations were a given, and Junior wanted to live up to them.

I suppose it had something to do with confidence. I mean, I'd always been the lowest Indian on the reservation totem pole—I wasn't expected to be good so I wasn't.

But in Reardan, my coach and the other players wanted me to be good. They needed me to be good. They expected me to be good. And so I became good.

I wanted to live up to expectations.

I guess that's what it comes down to.

The power of expectations.