Interoception and the negative self-evaluation bias of one's own speech in adults who stutter

Stuttering, a speech fluency disorder, is often accompanied by psychological difficulties, such as social anxiety. We hypothesize that adults who stutter (AWS) may experience a negative self-evaluation bias, where they over-focus on even minor disfluencies that listeners may not notice, resulting in an unfairly low self-rating of their speech. This heightened self-focus could be linked to interoception, the ability to perceive internal bodily states. This study aimed to quantitatively verify this self-evaluation bias and is the first to examine its relationship with interoceptive accuracy in this population.

Nineteen AWS and 39 fluent speakers (FS) participated. An evaluation gap (listener average score minus self-rated score) was calculated using a semantic differential scale for speech evaluation. Interoceptive accuracy (IAc), social anxiety, subjective impact of stuttering (OASES), and objective stuttering rate were also assessed.

Both groups showed a significant evaluation gap (self < listener). Across the entire sample, IAc, social anxiety, rater group, and age were significant predictors of this gap. Specifically, the gap in AWS was associated with IAc, OASES, and stuttering rate, whereas in FS, it was related to IAc, social anxiety, age, and rater group. A subsequent path analysis showed that OASES mediated the effect of social anxiety and age on this gap in AWS.

Higher interoceptive accuracy linked to negatively biased self-evaluation suggests that heightened accuracy in perceiving internal physiological cues-such as respiratory or articulatory effort-is associated with negative self-evaluation. This highlights the importance of interoception in the negative impact associated with stuttering.