On the road to social mobility? Affirmative action and major choice

Students from disadvantaged backgrounds are often underrepresented in prestigious and high-paying fields of study, such as STEM. While affirmative action (AA) policies have been shown to increase the representation of minority students in selective universities, they may also affect students’ choice of majors, with potential implications for social mobility. We exploit a policy implemented by a selective Brazilian university that expanded the range of majors available to lower-SES applicants, using it as a natural experiment. We find that the policy increased targeted students’ applications to, and acceptance into, prestigious STEM majors, and attenuated the influence of socioeconomic background on major choices. • Affirmative action increased public-school students’ applications to STEM. • Policy boosted admission of disadvantaged students into selective top-five majors. • Major-choice gap by socioeconomic background narrowed significantly post-policy. • Higher-ability students were most responsive to affirmative action incentives. • Policy reduced the parental income gradient in access to prestigious majors.