The effects of amount of exposure to response/outcome independence and teacher expressiveness on student ratings of the instructor, achievement test performance, and attribution items were studied. University students completed an aptitude test that provided contingent or noncontingent feedback and varied in length (short, medium, or long). All subjects, including a control group who did not complete the aptitude test, then viewed a videotaped lecture in a simulated classroom. Following the lecture, students completed a teacher evaluation, an achievement test, and an attribution questionnaire. The results reveal that contingent students scored higher than noncontingent students on the achievement test, and that students viewing the high expressive lecture performed significantly better than students in the low expressive condition. A priori comparisions of the contingency by expressiveness interaction indicated that the high expressive instructor attenuated the negative effects oF noncontingency. After viewing the low expressive lecture, noncontingent subjects had lower performance scores than contingent subjects, but there were no achievement differences between the three contingency conditions (control, contingent, noncontingent) when subjects viewed the high expressive lecture. Instructor expressiveness had the largest impact on the post-lecture measures. It accounted for the greatest amount of the achievement variance, and was the only variable to influence student ratings and attributions. It is concluded that exposure to contingent outcomes had a negative effect on achievement; however, instructor expressiveness had a larger overall effect on student performance. It is suggested that teacher behaviors such as expressiveness may attenuate the effects of exposure to noncontingency. A bibliography is included. (Author/SW)