The Monster Study: An Experiment That Turned Normal Children To Stutters

The “Monster Study” is an experiment credited to American Psychologist,  Wendell Johnson. It was conducted alongside Mary Tudor and was done under Johnson’s supervision at the University of Iowa in 1939. In the experiment, the psychologist used a negative and positive speech therapy to influence the children’s speech making psychology. However, it got it’s name as the “Monster Study” because Doctors were baffled that one of them could perform such an ugly experiment on twenty-two (22) children who were orphans. In 2001, University of Iowa made a public apology for the experiment.


They wanted to see the influence of using positive speech therapy on stutters in order to improve their speech making. After that, Mary Tudor started the selection process. It is noted that they never revealed the main purpose behind the experiment when they were selecting the twenty-two orphans.

Twelve of the selected children were stutters while the rest didn’t have any speech problem. Alongside other graduate students, Mary was able to score the speech fluency of all the children involved in the study on a scale of 1 – 5. The result also marched that which is obtainable in their normal schooling. Once that was complete, they moved to the next phase of the experiment.

In this stage, the children were segmented into four groups –

1] Group 1A: the experimental set. The children in this group were told their speech was good – 5 children.

2] Group IB: the control group. They were told their speech is “as bad as people say” – 5 children.

3] Group IIA: 5 – 15yrs old children were assigned to this group and told they were showing stuttering signs; they were normal speaking children – 6 children.

4] Group IIB – Normal speakers were added to this group and complimented for their good speeches.

They also assigned numbers to each of the children in the experimental group and used same to classify them in their observations of all focus groups. Mary will travel down to Davenport to observe and run the pre-planned script written for the experiment on the children. The study lasted from January – May, 1939. By the time the study ended, the children’s psyche has been distorted through the negative and positive speech therapy deployed for each of the various groups.

Children in Group IA’s speech making abilities improved drastically and they communicated well. However, not so much for the other groups, especially Groups IB and IIA. It’s also noted that their normal school performances were adversely affected by the experiment. Children who spoke very well started to stutter and actually started to believe that they are stutterers. Apparently, the negative reinforcement used by the psychologist influenced the way the children perceived their own speech making abilities. In time, they started to believe the negative and positive speech therapy being used on them. This singular act was noted to have caused a massive deterioration in the children’s psychology.

According to reports, the contents of the experiment are not published in any scientific publication. However, the observations and explanations it contains is credited to have helped in the study of stutters and how to help improve their speech making capacity. In 2005, the Supreme Court in Iowa gave a decision on the study which ensured the children [now adults] who were used in the ugly incident got damages from the State.


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