A study was designed (1) to discover the effect of teacher expectation on student performance in the cognitive and in the psychomotor skills, and (2) to analyze students' attitudes toward teachers because of teacher expectations. The study utilized two different instructional units. The quality milk production unit was used to teach cognitive skills with emphasis on class instruction and paper and pencil tests. The small gasoline engine unit was used to teach certain psychomotor skills. Each instructional unit was taught in two comprehensive high schools. Students within each class were divided into three groups. Group one, positive expectancy students, received constructive comments on their assignments and appropriate teacher behavior during the experiment. Group two, constructive expectancy students, received constructive comments on the assignments and appropriate teacher behavior during the experiment. Group three, control group students, received no comments on their assignments and no expectancy interaction from teachers. After one month of instruction, students were tested in each subject area. Students' attitudes toward the teacher and subject were also measured before and after the experiment. The findings revealed that the teacher's expectations did change the students' attitudes toward the teacher and subject; however, written comments by the teacher on students' assignments had no significant effect on the level of student achievement. (Author/CSS)