10 Times Well-Loved Scientists Were Total Jerks

The Monster Study is the unofficial name given to a stuttering experiment that took place in 1939 at the University of Iowa. Two researchers named Wendell Johnson and Mary Tudor, took a sample of 22 orphan children and split them into two groups. 

Both groups were given speech therapy, but one was consistently showered with praise for their good progress. However, the other group were repeatedly given negative feedback and essentially bullied by a couple of grown adults about their speech. 

The therapists would say things like "Don't ever speak unless you can do it right. You see how [the name of a child in the institution who stuttered severely] stutters, don't you? Well, he undoubtedly started this very same way."

By the end of the experiment, many of the children from the negative group had developed severe communication problems, including one 9-year-old girl who "practically refused to speak". Johnson and Tudor were horrified by the results of the experiment and never published them for fear of being associated with the Nazi human experiments that had recently come to light.

Tudor has since tried to make amends for the experiment, often visiting the orphanage to try and repair the damage, and an official apology from the pair was eventually released in 2001.