The University of Iowa conducted an experiment on orphan kids later called the 'Monster Study!'

It’s an ominous but revealing title. In 1939, Wendell Johnson conducted a stuttering experiment on 22 orphaned children. The children were placed in control and experimental groups and half of the children were given positive reinforcement for their speech while the other half was belittled, ridiculed, and accused on constantly stuttering.

Many of the children who went into the experiment speaking normally and received negative reinforcement came out with speech problems that they suffered from their entire lives. The experiment and it's results were initially hidden to protect Johnson’s reputation. However, the University of Iowa publically apologized for the Monster study in 2001.

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