In 1938, Mamie Clark graduated magna cum laude from Howard University, and immediately enrolled in the psychology graduate program. Her master's thesis, "The Development of Consciousness of Self in Negro Pre-School Children," was the beginning of a line of research that became historic when it was used to make racial segregation unconstitutional in American public schools. Her thesis concluded that children became aware of their "blackness" very early in their childhood, and it was precisely this conclusion that became the foundation and the guiding premise for the Clark's famous doll studies.