Angry, old, male - and trustworthy? How expressive and person voice characteristics shape listener trust

It's not what you say but how you say it: Examining the influence of perceived voice assistant gender and pitch on trust and reliance

Voice assistants (VA) are virtual agents used to aid information seeking. Cues contained in speech, such as perceived gender and vocal pitch, may influence attitudes towards, and interactions with these agents. Given expansion of telehealth efforts and the potential for VA to advise patients on health-related topics outside of formal healthcare settings, the influence of VA vocal characteristics is examined in the context of medication instructions. Participants rated trust and reliance on VA after viewing medication labels and hearing recommendations from male and female agents with varying pitch. Results suggest agents perceived as female were rated as more trustworthy, while vocal pitch did not significantly influence trust. However, a trend of lower reliance with increasing pitch was observed. Additionally, participants relied significantly more on VA advice than medication labels when making decisions. Post-hoc analyses revealed trust and reliance primarily varied between participants. Pitch and gender explained only a small portion of within-participant variance. We found suggestive evidence for social categorizations distilled from vocal cues influencing interactions with agents delivering health-critical information. Future work should explore additional samples, vocal cues, and participant-level sources of variation.

Angry, old, male - and trustworthy? How expressive and person voice characteristics shape listener trust

This study examined how trustworthiness impressions depend on vocal expressive and person characteristics and how their dependence may be explained by acoustical profiles. Sentences spoken in a range of emotional and conversational expressions by 20 speakers differing in age and sex were presented to 80 age and sex matched listeners who rated speaker trustworthiness. Positive speaker valence but not arousal consistently predicted greater perceived trustworthiness. Additionally, voices from younger as compared with older and female as compared with male speakers were judged more trustworthy. Acoustic analysis highlighted several parameters as relevant for being perceived as trustworthy (i.e., accelerated tempo, low harmonic-to-noise ratio, more shimmer, low fundamental frequency, more jitter, large intensity range) and showed that effects partially overlapped with those for perceived speaker affect, age, but not sex. Specifically, a fast speech rate and a lower harmonic-to-noise ratio differentiated trustworthy from untrustworthy, positive from negative, and younger from older voices. Male and female voices differed in other ways. Together, these results show that a speaker’s expressive as well as person characteristics shape trustworthiness impressions and that their effect likely results from a combination of low-level perceptual and higher-order conceptual processes.

Does he sound cooperative? Acoustic correlates of cooperativeness

The sound of the voice has several acoustic features that influence the perception of how cooperative the speaker is. It remains unknown, however, whether these acoustic features are associated with actual cooperative behaviour. This issue is crucial to disentangle whether inferences of traits from voices are based on stereotypes, or facilitate the detection of cooperative partners. The latter is likely due to the pleiotropic effect that testosterone has on both cooperative behaviours and acoustic features. In the present study, we quantified the cooperativeness of native French-speaking men in a one-shot public good game. We also measured mean fundamental frequency, pitch variations, roughness, and breathiness from spontaneous speech recordings of the same men and collected saliva samples to measure their testosterone levels. Our results showed that men with lower-pitched voices and greater pitch variations were more cooperative. However, testosterone did not influence cooperative behaviours or acoustic features. Our finding provides the first evidence of the acoustic correlates of cooperative behaviour. When considered in combination with the literature on the detection of cooperativeness from faces, the results imply that assessment of cooperative behaviour would be improved by simultaneous consideration of visual and auditory cues.