From Mike Rose’s great literacy history “‘I Just Wanna Be Average'” (in Considering Literacy, ed. Linda Adler-Kassner, p. 176) comes a superb statement about how students respond to teachers’ expectations:

Students will float to the mark you set.

And I think this is true: Students will only achieve what they think you believe they can do, and not a bit more. For Rose, he was in a group of “Voc. Ed.” kids (i.e. students in a vocational or low-achieving track), and no one in the group aspired to anything because they didn’t believe they could do it.

Teachers cannot do this.

We have to be willing to let students succeed, but we also have to push them to better things. We have to make them think that they are capable of more than just “being average” (as Rose recalls a peer saying in one of his classes), or there is only one alternative: they will be average, and we will have been an party to that fate.