Voice of Authority: Professionals Lower Their Vocal Frequencies When Giving Expert Advice

Acoustic analysis and playback studies have greatly advanced our understanding of between-individual differences in nonverbal communication. Yet, researchers have only recently begun to investigate within-individual variation in the voice, particularly how people modulate key vocal parameters across various social contexts, with most of this research focusing on mating contexts. Here, we investigated whether men and women modulate the frequency components of their voices in a professional context, and how this voice modulation affects listeners’ assessments of the speakers’ competence and authority. Research assistants engaged scientists working as faculty members at various universities in two types of speech conditions: (1) Control speech, wherein the subjects were asked how to get to the administrative offices on that given campus; and (2) Authority speech, wherein the same subjects were asked to provide commentary for a radio program for young scholars titled, “How to become a scientist, and is it worth it?”. Our results show that male (n = 27) and female (n = 24) faculty members lowered their mean voice pitch (measured as fundamental frequency, F ₀ ) and vocal tract resonances (measured as formant position, P _f ) when asked to provide their expert opinion compared to when giving directions. Notably, women lowered their mean voice pitch more than did men (by 33 Hz vs. 14 Hz) when giving expert advice. The results of a playback experiment further indicated that foreign-speaking listeners judged the voices of faculty members as relatively more competent and more authoritative based on authority speech than control speech, indicating that the observed nonverbal voice modulation effectively altered listeners’ perceptions. Our results support the prediction that people modulate their voices in social contexts in ways that are likely to elicit favorable social appraisals.