Scientific research is viewed as uncollaborative; yet little is known regarding when, and for whom, such perceptions emerge and whether these fluctuating perceptions matter. We investigated students’ development of perceiving research as a collaborative, team-based endeavor and the resulting motivational consequences. Among 522 biomedical RAs across 10 universities/colleges, longitudinal analysis showed that after only a short exposure to research, students’ social-collaborative science perceptions decreased. This is troubling given our results showing greater social-collaborative science perceptions predicted enhanced intrinsic interest in science over time, which in turn predicted greater intentions to attend a biomedical graduate program. Using an intersectionality lens, we also found ethnic minority women (compared to other groups) showed the most stability in social-collaborative science perceptions over time. Results underscore the potential impact of mentors creating an inclusive team science environment early in students’ training to discourage “opting out” of science. We discuss implications for broadening participation in the scientific workforce. (PsycINFO Database Record (c) 2018 APA, all rights reserved)