Although preferred student explanations for failure (high ability/low effort) lead to a conflict in student-teacher values, self-worth theory predicts that high effort is a shared value in success, since it poses no threat to the student's sense of competency. To test this assertion, 360 undergraduates rated their affective reactions to hypothetical test performances under 4 conditions of success. Then, in the role of teachers, they administered rewards to hypothetical students under identical conditions. Results indicate that both positive self-evaluation and teacher praise were greatest when success followed much effort. Conversely, both student pride and teacher reward were reduced when conditions of success detracted from the causal role of effort. Not only effort but also perceptions of ability enhanced positive affect. Consequently, students preferred to be seen as both able and motivated. (59 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1979 American Psychological Association.