This study tested a causal model of influences on white students' perceptions of racism toward minority students on predominantly white college campuses. The study was part of the National Study of Student Learning and utilized a three-wave, longitudinal design. The institutional sample consisted of 11 traditional institutions in 9 states. The study surveyed students before starting their first year of college, after their first year, and after their second year. Of the original 2,137 students who participated in the first survey, 1,200 completed the final survey. Results suggested that white students' background, their attitudes toward diversity, the types of institutions they attended, and their behavior during college all affected their perceptions of racism toward minority students on campus. Students who were more open to diversity before college were more likely to make friends with students of other races and discussed social issues with greater frequency. Significant differences between men and women were found in openness to diversity before college, perhaps reflecting the less favorable attitudes toward diversity among "angry white men" in the broader society during the early 1990s. White students' perceptions were shaped directly and most significantly by their openness to diversity before starting college and by the undergraduate racial mix at the institution they attended. (Contains 45 references.) (JB)