Adults who stutter do not stutter during private speech

Purpose

Adults who stutter tend not to stutter when they are alone. This phenomenon is difficult to study because it is difficult to know whether participants perceive that they are truly alone and not being heard or observed. This may explain the presence of stuttering during previous studies in which stutterers spoke while they were alone. We addressed this issue by developing a paradigm that elicited private speech, or overt speech meant only for the speaker. We tested the hypothesis that adults do not stutter during private speech.

Method

Twenty-four participants were audio-/video-recorded while speaking in several conditions: 1) conversational speech; 2) reading; 3) private speech, in which deception was used to increase the probability that participants produced speech intended for only themselves; 4) private speech+, for which real-time transcription was used so that participants produced the same words as in the private speech condition but while addressing two listeners; and 5) a second conversational speech condition.

Results

Stuttering was not observed in more than 10,000 syllables produced during the private speech condition, except for seven possible, mild stuttering events exhibited by 3 of 24 participants. Stuttering frequency was similar for the remaining conditions.

Conclusions

Adults appear not to stutter during private speech, indicating that speakers' perceptions of listeners, whether real or imagined, play a critical and likely necessary role in the manifestation of stuttering events. Future work should disentangle whether this is due to the removal of concerns about social evaluation or judgment, self-monitoring, or other communicative processes.