Footnote 11 in the Brown decision cited numerous social science studies that showed how segregation harmed black children and imposed on them feelings of inferiority. The first work cited was that of social scientist Kenneth B. Clark, well known for his studies involving the effects of segregation. Clark tested African American students in Philadelphia, Boston, and other cities by showing them white and black dolls. A large percentage of students preferred the white dolls. Critics charged that the Court relied too much on imprecise social science studies rather than on more concrete constitutional law principles.