Sensing Robots and Social Odor: How Relational Engagement and Trust Change

Exploring the interaction dynamics between humans and robots also entails examining the exchange of multisensory signals. In this light, this study explores the role of social odors (putative pheromones) in shaping human-robot interactions (HRI) beyond the conventional focus on visual and auditory cues. Our research examines how these odors influence relational engagement (RE; assessed as co-presence and social presence) and trust (dispositional and situational) during interactions with the humanoid social robot (HSR) NAO. The robot was also equipped with a male or female voice, to better counteract odor-related gender differences. Thirty participants engaged in storytelling sessions with NAO under different sensory conditions. Our findings indicate odors significantly affecting trust, especially when resembling female pheromones. Conversely, odors had a nuanced influence on RE, despite participants reporting greater CoPre than SoPre. Additionally, a bidirectional relationship between SoPre and trust emerged, reinforced by sensory congruence. These results highlight the significance of sensory alignment in shaping socio-relational and trust dynamics and emphasize the potential of olfactory stimuli in enhancing human-robot interactions. By deepening our understanding of the complex interplay among olfactory cues, voice gender, RE, and trust within HRIs, we provide valuable insights for crafting and deploying HSRs that are more relatable and trustworthy.