This experiment was conducted by Dr. Wendell Johnson, a speech pathologist who wanted to show that the prevailing theories about the causes of stuttering were wrong. During the 1930s it was thought that stuttering had an organic or genetic cause. This meant you were born a stutterer (or not) and little could be done.

Dr. Johnson believed that the labelling of children as stutterers could actually make them worse, and in some cases cause ‘normal’ children to start stuttering. To prove his point, he suggested an experiment which has since become known as the ‘Monster Study’.

Twenty-two young orphans were recruited to participate in the experiment. They were then divided into two groups. The first were labelled ‘normal speakers’ and the second ‘stutterers’. Crucially only half of the group labelled stutterers did actually show signs of stuttering.

During the course of the experiment, the normal speakers were given positive encouragement but it was the treatment of the other group that has made the experiment notorious. The group labelled stutterers were made more self-conscious about stuttering. They were lectured about stuttering and told to take extra care not to repeat words. Other teachers and staff at the orphanage were even unknowingly recruited to reinforce the label as the researchers told them the whole group were stutterers.

Of the six ‘normal’ children in the stuttering group, five began stuttering after the negative therapy. Of the five children who had stuttered before their ‘therapy’, three became worse. In comparison, only one of the children in the group labelled ‘normal’ had greater speech problems after the study.

Realising the power of their experiment, the researchers tried to undo the damage they had done, but to no avail. It seemed the effects of labelling the children stutterers was permanent. This is something the orphans labelled stutterers have had to cope with for the rest of their lives.

Clearly this research raises a number of major ethical concerns, despite the good intentions of the researcher. In 2001 the University of Iowa, where the study was conducted, issued a formal apology and called the experiment both regrettable and indefensible.