Two questions were addressed: "What are students' beliefs about the nature of knowledge?" and "How do these beliefs affect comprehension?" In Experiment 1, an epistemological questionnaire was administered to undergraduates. Factor analysis of the questionnaire resulted in 4 factors reflecting degrees of belief in innate ability, simple knowledge, quick learning, and certain knowledge. In Experiment 2, students read a passage about either the social sciences or the physical sciences, in which the concluding paragraph was removed. Then they related their confidence in understanding the passage, wrote a conclusion, and completed a mastery test. Belief in quick learning predicted oversimplified conclusions, poor performance on the mastery test, and overconfidence in test performance. Belief in certain knowledge predicted inappropriately absolute conclusions.