This paper presents the results of eight analyses based upon data from the National Study of Student Learning (NSSL), a 3-year longitudinal research project begun in 1992 to examine the influence of academic and nonacademic experiences on student learning, student attitudes about learning, student cognitive development, and student persistence. Eighteen four-year and five two-year postsecondary institutions participated in the study, with data collected from a total of 3,840 students. The eight analyses focused on the effects of: (1) two- and four-year colleges on cognitive development; (2) historically black and predominantly white colleges on cognitive development; (3) teacher behavior on cognitive development; (4) first-generation college attendance on cognitive development and attitudes; (5) intercollegiate athletic participation on cognitive development; (6) institutional environment and students' academic and nonacademic experiences on students' development of openness to cultural and racial diversity; (7) Greek affiliation on cognitive development during the first year of college; and (8) in-class and out-of-class experiences on first-year students' critical thinking ability. These analyses found little difference in the cognitive gains made by students attending two-year versus four-year institutions, or historically black versus predominantly white institutions. Other results are presented and discussed. (Contains 40 references.) (MDM)