The Monster Study was a non-consensual experiment performed on 22 orphan children in Davenport, Iowa in 1939 about stuttering. It was conducted by Wendell Johnson, University of Iowa, with the physical experiment being performed by his graduate student Mary Tudor.
The study was never published, and as a result was relatively unknown until 2001 San Jose Mercury News article conducted by an investigative reporter, Jim Dyer, revealed both the details and followed up with the former test subjects who were still living - none of whom were ever told it was an experiment. A lawsuit took place and the 7 test subjects from the "negative-reinforcement" group who were told they stutter but did not were awarded $925,000 by the State of Iowa for lifelong psychological and emotional scars.
The nickname "Monster Study" was coined in the 40s and 50s by those associated with the Stuttering Research Program at University of Iowa who knew about it.[1] Some assume it was due to Johnson's peers being horrified that he would experiment on orphan children to confirm a hypothesis. Others suggest it is due to what was said to the children themselves that was considered monstrous. Regardless, Tudor's thesis is the only official record of the details of the experiment.[2]