The Monster Study was a stuttering experiment on 22 orphan children in Davenport, Iowa, in 1939 conducted by Wendell Johnson at the University of Iowa. Johnson chose one of his graduate students, Mary Tudor, to conduct the experiment and he supervised her research. After placing the children in control and experimental groups, Tudor gave positive speech therapy to half of the children, praising the fluency of their speech, and negative speech therapy to the other half, belittling the children for every speech imperfection and telling them they were stutterers. Many of the normal speaking orphan children who received negative therapy in the experiment suffered negative psychological effects and some retained speech problems during the course of their life. Dubbed “The Monster Study” by some of Johnson’s peers who were horrified that he would experiment on orphan children to prove a theory, the experiment was kept hidden for fear Johnson’s reputation would be tarnished in the wake of human experiments conducted by the Nazis during World War II. The University of Iowa publicly apologized for the Monster Study in 2001.