Researchers have developed an experiment to test the effect of speech alone in stuttering adults. These studies confirm that the subjects concerned do not stutter during private speech. The perceptions of listeners, real or imaginary, would therefore play an essential role in speech fluency problems.
Stuttering is a disorder of the flow or rhythm of speech generally characterized by repetitions of words and syllables, prolongations of sounds and/or blockages that give the impression of an effort. It is believed that more than 70 million people worldwide suffer from it daily.
We know that stuttering tends to stop in private speech, such as when addressing oneself or an animal. But there is plenty of anecdotal evidence for this phenomenon, it has never been confirmed in the laboratory, "mainly because it is difficult to create conditions in which people believe that they are truly alone" , points out Eric Jackson, speech therapist and researcher at New York University.
With his team, Dr. Jackson therefore set up an experiment to try to understand this phenomenon.
As part of this work, the researchers recruited twenty-four volunteers. All were audio/video recorded while speaking under several conditions:conversational speech, reading, private speech, in which deception was used to increase the likelihood of participants producing speech intended only for themselves. But also private speech+, for which real-time transcription was used so that participants produce the same words as in the private speech condition, but addressing two listeners; and a second conversational speech condition.
For the private speech scenario, participants were given a trio of challenging computer coding tasks, tasks known to get people talking to themselves. The volunteers were falsely told that no one would listen while they performed the computer task. In reality, they were still monitored and recorded by researchers. As a result, during this exercise, stuttering was almost non-existent in the 24 study participants.
“Stuttering was not observed in more than 10,000 syllables produced during the private speech condition, except for seven possible mild stuttering events presented by three of the twenty-four participants" , write the authors. "Conversely, the frequency of stuttering was similar for the other conditions" .
These works in particular, published in the Journal of Fluency Disorders, only make an observation. The next step will be to find out why lack of hearing has such a big effect on speech fluency issues. For the researchers, the feeling of being judged or evaluated could play a very important role, but it is probably not the only factor. Many stutterers indeed stop stuttering on stage, when they sing or do theatre, for example.
Finally, it would also be interesting to understand at what stage social considerations begin to affect young children who stutter.
