A study was conducted involving two experiments to address the question "What effects do students' beliefs about the nature of knowledge have on comprehension?" Experiment one involved 117 junior college students and 149 university students as subjects. An epistemological questionnaire was administered to the undergraduates. Factor analysis of the questionnaire resulted in four factors reflecting degrees of beliefs in innate ability, simple knowledge, quick learning, and certain knowledge. In experiment two, 86 of the junior college students who participated in experiment one read a passage from either the social sciences or the physical sciences, in which the concluding paragraph was removed. They rated their confidence in understanding the passage, wrote a conclusion, and completed a mastery test. Belief in "quick learning" predicted oversimplified conclusions and belief in "certain knowledge" predicted inappropriately absolute conclusions. Belief in quick learning predicted poor performance on the mastery level test and confidence rating. Results indicated that epistemological beliefs should be conceptualized in terms of several independent dimensions, each with distinct effects on comprehension. (Six tables of data are included and 24 references are attached.) (MG)