They generally select majors that pay the least....
https://cew.georgetown.edu/cew-reports/african-american-majors/
Earnings vary greatly among college majors. While college access has increased among African Americans, they are overrepresented in majors that lead to low-paying jobs. African Americans: College Majors and Earnings shows that African Americans, who represent 12 percent of the U.S. population, are underrepresented in the number of college majors associated with the fastest growing, highest-paying occupations.