Doll Test: The Effects of Racism on Children In the 1940s, psychologists Kenneth and Mamie Clark designed and conducted a series of experiments known colloquially as “the doll tests” to study the psychological effects of segregation on African-American children.Drs. Clark used dolls, identical except for color, to test children’s racial perceptions. Their subjects, children between the ages of three to seven, were asked to identify both the race of the dolls & which color doll they prefer. A maj