The Kenneth en Mamie Clarks' doll experiments grew out of Mamie Clark's master's degree thesis. They published three major papers between 1939 and 1940 on children's self perception related to race. Their studies found contrasts among African-American children attending segregated schools in Washington, DC versus those in integrated schools in New York. The doll experiment involved a child being presented with two dolls. Both of these dolls were completely identical except for the skin and hair color. One doll was white with yellow hair, while the other was brown with black hair. The child was then asked questions inquiring as to which one is the doll they would play with, which one is the nice doll, which one looks bad, which one has the nicer color, etc. The experiment showed a clear preference for the white doll among all children in the study. These findings exposed internalized racism in African-American children, self-hatred that was more acute among children attending segregated schools. This work suggests that by its very nature, segregation harms children and, by extension, society at large, a suggestion that was exploited in several legal battles.