Research has shown that the prophesies which teachers make about the achievement of specific students (based on their analysis of student past achievements and intelligence ratings) are often self-fulfilling; teachers usually get what they expect from students. This phenomenon becomes dangerous to learning only when the teacher's low expectations cause low achievement in a student whose past achievements and intelligence have not been correctly analyzed, when a teacher cannot adjust to a student classified as a low achiever who performs well, and when a teacher's mistakenly pessimistic judgment colors the student's own self-evaluation. This problem is especially prevalent when teachers deal with students from different cultural backgrounds (such as Mexican-Americans); the information on which teachers base their prophesies is often misleading (as in the case of most intelligence tests which test knowledge of American culture and not learning ability), and the factors which motivate these students are not understood by most teachers. To break this cycle of low expectation-low achievement, teachers must become more sensitive to the needs of the disadvantaged student and to their own interactional verbal and nonverbal defense mechanisms which communicate harmful expectations to the student. (SP)