Summary: New evidence shows that many adults who stutter speak fluently when they believe they are truly alone. The study suggests that the perception of being heard — and the social evaluation that comes with it — plays a central role in whether stuttering occurs.
Source: NYU
The so-called “talk-alone-effect”—the idea that people who stutter may be fluent when speaking alone—has been reported anecdotally for years. This new study provides controlled laboratory evidence supporting that effect.
A recent article in the Journal of Fluency Disorders, led by NYU Steinhardt Professor Eric S. Jackson, investigates the talk-alone-effect and the influence of social context and perceived listeners on stuttering. Titled “Adults who stutter do not stutter during private speech,” the paper reports that when participants believed no one could hear them, stuttering essentially disappeared. The authors argue that the perception of being listened to or evaluated is a key factor in whether stuttering emerges.
“Many people who stutter say they are fluent when they’re alone, but replicating that situation in a lab is challenging because it’s hard to make participants feel genuinely unobserved,” Jackson explains. The study introduces a novel approach designed to create a convincing private-speech scenario and examines how speech differs across social and non-social contexts.
Twenty-four adult participants completed five speaking tasks: conversational speech, reading aloud, a private speech task designed to make them feel unobserved, a repeat of the private speech while addressing two listeners (using real-time transcription), and another spontaneous conversation. All tasks were audio- and video-recorded. Except for the private speech condition, the tasks involved speaking to or for others in some way.
To elicit authentic private speech, participants were asked to perform a challenging computer programming exercise that prior research shows often prompts people to talk aloud to themselves. The researchers used a carefully reviewed deception protocol to convince participants that no one could hear them and encouraged self-directed speech by suggesting that talking out loud could improve task performance.
Across more than 10,000 syllables produced during the private speech condition, stuttering events were essentially absent; only three participants produced a total of seven mild, possible stuttering instances. In contrast, stuttering occurred at measurable rates in the conditions that involved listeners or the expectation of being heard.
The research protocol, including the use of deception, received Institutional Review Board approval at NYU. After the private-speech task, participants were debriefed about the deception and provided informed consent to continue with the study procedures.
Jackson emphasizes the broader implication: “These findings indicate stuttering is not solely a motor or speech production issue. Perceptions about being heard and the potential for social evaluation appear to be central triggers.” When speakers believe no one is listening, concerns about judgment or evaluation vanish, and so does much of the stuttering observed in social settings.
The authors recommend expanding this line of research to younger populations. Examining private speech in children could clarify when social awareness begins to shape fluency and how early social factors contribute to the development and persistence of stuttering.
Co-authors on the study include Lindsay Miller, a speech-language pathologist and NYU Steinhardt alumna; Haley Warner, a speech-language pathologist and doctoral candidate at NYU Steinhardt; and J. Scott Yaruss, a professor at Michigan State University.
Funding: This research was supported by a grant to Eric S. Jackson from the National Institute of Deafness and Other Communication Disorders.
About this language research news
Author: Jade McClain
Source: NYU
Contact: Jade McClain – NYU
Image: The image is in the public domain
Original Research: Closed access. “Adults who stutter do not stutter during private speech” by Eric S. Jackson et al., Journal of Fluency Disorders
Abstract
Adults who stutter do not stutter during private speech
Purpose
Adults who stutter often report greater fluency when they speak alone. Prior lab studies have struggled to reproduce that effect because it is difficult to ensure participants truly feel unobserved. This study developed a method to elicit private speech—overt speech produced only for the speaker—and tested whether adults who stutter remain fluent under those conditions.
Method
Twenty-four adults who stutter were recorded across five conditions: conversational speech, reading aloud, a private speech condition that used deception to encourage speech addressed only to oneself, a “private speech+” condition where the same words were produced while addressing two listeners via real-time transcription, and a second conversational task. The design allowed direct comparison between private, listener-directed, and conversational speaking.
Results
During the private speech condition, stuttering was essentially absent across more than 10,000 syllables, with only seven possible mild events from three participants. Stuttering frequency in the listener-directed and conversational conditions was comparable to typical rates observed in laboratory studies.
Conclusions
The study concludes that adults who stutter do not generally stutter when producing private speech. These results point to the importance of perceived listeners and social evaluation in triggering stuttering. Future research should clarify whether the effect arises from reduced concern about social judgment, changes in self-monitoring, or other communicative mechanisms, and should investigate how these dynamics develop in childhood.