Does having a voice disorder hurt credibility?

The purpose of the study was to determine whether listeners were less likely to believe a statement that is produced in an atypical voice, as compared to a typical voice. It was hypothesized that an atypical voice, characterized by abnormal roughness, strain, and pitch, would elicit increased skepticism. This hypothesis was based on previous evidence that there are negative stereotypes against individuals who have a voice disorder, and that increased difficulty processing an utterance can lead to disbelief.

In Experiment 1, 36 listeners rated obscure trivia statements (such as "the elephant is the only mammal that cannot jump" and "the first public library was opened in Vienna in 1745") as definitely false, probably false, probably true, or definitely true. The statements were produced by a speaker who used their typical voice and simulated an atypical voice (of severe deviance according to the CAPE-V), as well as two additional control speakers with typical voices. Experiment 2 was a replication of Experiment 1 with a new set of 36 listeners and a new set of speakers. In addition, Experiment 2 examined whether reduced credibility was due to negative stereotypes and/or processing difficulty, through questionnaire data and correlation analyses.

The results were largely consistent with the hypothesis that statements produced in an atypical voice would be perceived as less credible. In both experiments, the percentage of definitely false ratings was higher for the atypical voice than for the typical voice and control voices, with a large effect size in Experiment 1 and a medium effect size in Experiment 2. Further, Experiment 2 suggested that reduced credibility was due to negative stereotypes but not processing difficulty.

The current study reveals a social consequence of having a voice disorder, i.e., decreased perceived credibility, with implications for job-related success.