In this study, we use an experimental methodology called policy capturing to examine the effects of contextual barriers and supports on students' decisions to change academic majors. Consistent with Social Cognitive Career Theory (SCCT), we found that information about family supportiveness, peer supportiveness, financial status, and job market outlook all had unique effects on participants' decisions, as did choice self-efficacy. Further, we found that trait negative affectivity moderated the relationship between choice self-efficacy and choice decisions. Exploratory analyses also indicated that the relations of family and peer supportiveness to choice decisions were weaker for non-European-American participants than European-American participants. Implications and directions for future research are discussed. (Contains 2 figures and 2 tables.)