The Sound of Trust: Voice as a Measurement of Trust During Interactions with Embodied Conversational Agents

Trust is a critical component in effective collaboration, decision-making and negotiation. The goal of effective team leaders should be to send signals and messages that increase trust. We attempt to determine if signals can vary perceptions of trustworthiness and if nonverbal behaviors, such as the voice, contain indicators of trust. In order to investigate the relationship between trust and vocal dynamics, this article presents a study that explores how the voice, measured unobtrusively, reflects a person’s current level of perceived trust. We used an Embodied Conversational Agent (ECA) to maximize consistency and control in questioning, timing, and interviewer nonverbal behavior, thus eliminating potential confounds that may be introduced due to interaction adaptation. Participants ( $$\text{ N}=88$$ ) completed a face-to-face interview with the ECA and reported their perceptions of the ECA’s trustworthiness. The results of the study revealed that vocal pitch was inversely related to perceived trust, but temporally variant; vocal pitch early in the interview reflected trust. The ECA was perceived as more trustworthy when smiling. While the results of this research suggest a relationship between vocal pitch and perceived levels of trust, more work needs to be done to clarify the causal relationship. Similarly, additional study needs to be done in order to integrate additional behavioral measurements that account for variation across diverse situations, people, and cultures.