Significance In the United States, large, persistent gaps exist in the rates at which racial, ethnic, and socioeconomic groups complete postsecondary education, even when groups are equated on prior preparation. We test a method for preventing some of those gaps by providing individuals with a lay theory about the meaning of commonplace difficulties before college matriculation. Across three experiments, lay theory interventions delivered to over 90% of students increased full-time enrollment rates, improved grade point averages, and reduced the overrepresentation of socially disadvantaged students among the bottom 20% of class rank. The interventions helped disadvantaged students become more socially and academically integrated in college. Broader tests can now be conducted to understand in which settings lay theories can help remedy postsecondary inequality at scale.
