Leila McNeill in Smithsonian:
From a young age, Mamie Phipps Clark knew she was black. “I became acutely aware of that in childhood, because you had to have a certain kind of protective armor about you, all the time … You learned the things not to do…so as to protect yourself,” she would say later, when asked in an interview how she first became aware of racial segregation. Growing up attending an all-black school in Hot Spring, Arkansas left an indelible impression on Clark; even as a young child, she knew that when she grew up she wanted to help other children. And help children she did. Clark would go on to study psychology and develop valuable research methodology that combined the study of child development and racial prejudice— helping her field incorporate the felt experience of childhood racism. Ultimately, her work in social psychology crossed over into the Civil Rights Movement: Her research and expert testimony became instrumental to ending school segregation across the country in the landmark Brown v. Board of Education case of 1954.
…Her master’s thesis, “The Development of Consciousness in Negro Pre-School Children,” surveyed 150 black pre-school aged boys and girls from a DC nursery school to explore issues of race and child development—specifically the age at which black children become aware that they were black. For the study that formed the basis of her thesis, she and Kenneth recruited the children and presented them with a set of pictures: white boys, black boys, and benign images of animals and other objects. They asked the boys to pick which picture looked like them, and then asked the girls to pick which picture looked like their brother or other male relative. The conclusion of the study showed a distinct racial awareness of self in boys aged three to four years. The results were, in Kenneth’s words, “disturbing.”