This paper examines the developmental trajectories of students' self-authored worldview commitments over four years of college and the reasons they offered for making associated developmental gains. Through a longitudinal, mixed methods approach, we unearthed four distinctive developmental trajectories of a nationally-representative cohort of 9,470 students enrolled across 122 institutions. We found that provocative encounters with worldview diversity -- those that appropriately challenged students to examine their own religious commitments -- served as catalysts for growth during college. The varied contexts of those provocative encounters, both inside and outside the college classroom, are highlighted in students' own words. Implications for research are discussed.