The Monster Study was a stuttering experiment performed on 22 orphan children in Davenport, Iowa in 1939. It was conducted by Wendell Johnson at the University of Iowa. Mary Tudor conducted the experiment under Johnson’s supervision. Half of the children received positive speech therapy, praising the fluency of their speech, and the other half, negative speech therapy, belittling the children for speech imperfections. Many of the normal speaking orphan children who received negative therapy in the experiment suffered negative psychological effects and some retained speech problems for the rest of their lives.