Perception of disfluency in people who stutter and people who do not stutter: Results from magnitude estimation

Recent accounts of stuttering [7, 15] consider disfluencies the result of an interaction between speech planning and selfmonitoring, emphasizing the continuity between errors made in everyday speech and those made by people who stutter. On Vasic & Wijnen’s [14, 15] account, the monitor is hypervigilant for upcoming problems and interrupts and restarts the speech signal, resulting in disfluent speech. Crucially, on this account, self-monitoring is a perceptual function. Therefore, this account makes two predictions (1) people who stutter are also hypervigilant in perceiving another person’s speech. (2) the quality of disfluencies made by people who stutter and those who do not will be comparable. We tested these hypotheses using a magnitude estimation judgment task. Twenty participants who stutter and 20 controls were asked to rate the fluency of excerpted fluent and disfluent fragments from recorded dialogues, either between people who stutter or between non-stutterers. In line with the first hypothesis, people who stutter tended to rate all fragments as more disfluent than controls did. However the second hypothesis was not confirmed: across judges, fluent and disfluent fragments excerpted from recordings of people who stutter were rated as less fluent than those excerpted from control dialogues, suggesting that there are perceptually relevant differences between the speech of PWS and PWDNS, independent of number and type of disfluencies.