Diversifying the STEM workforce is a national priority, yet white males continue to dominate the ranks of professional scientists and engineers in the United States. This is partly due to disparities in academic success for women and minoritized students in prerequisite introductory STEM courses, leading to higher attrition from B.S. degree programs. Past research has demonstrated that when social-psychological interventions targeting "stereotype threat" or "fixed" mindsets are implemented in STEM courses, equity gaps may be significantly reduced. We incorporated two such interventions into introductory biology courses for life science B.S. majors and Associate's degree allied health students taught at a regional research university and a community college. We observed no significant effects of the values-affirmation interventions on grade outcomes for students in any of the courses, regardless of students' gender identity, race/ethnicity, or first-generation status, suggesting that students, on average, were not experiencing stereotype threat on either campus. We found a significant positive association between completing more weekly reflective journal entries and higher mean content-based grades for students in the university majors course overall, especially first-generation students, although the association was significantly negative for women. Our results confirm that context matters when implementing interventions aimed at reducing achievement gaps, and we propose that educators assess their students' social-psychological characteristics and then select interventions accordingly.