Trust, (Dis)Comfort, and Voice Quality: Anthropomorphism in Verbal Interactions with NAO

The endeavour to develop technologies which approach human faculties, whether in functionality or physical resemblance, has gained heightened momentum, leading to intensified attention to anthropomorphism in human-machine interaction. Anthropomorphism can be characterized as the process of attributing human properties, such as motivation, behaviours, and social roles to non-human entities. This inclination is notably pronounced in interactions with social robots, which can exhibit varying degrees of human-like attributes such as facial expressions and voices resembling those of human. Human-like voices. With machines becoming increasingly conversational and escalating expectations for more personalized interactions, voice-based interfaces have assumed more and more significance in human-machine relations. In this study, two groups of participants (A, B) verbally interacted with a NAO robot about an emotionally charged topic (‘depression’). In group (A) NAO’s voice was synthetic. In group (B) NAO's voice replicated a female human voice, created from a pre-recorded voice sample. Visual analysis during interactions and post-experimental interviews showed that NAO's voice significantly contributed to emotional states like feelings of uneasiness or discomfort. A majority of participants described the relationship between the physical appearance of NAO and the human-like voice as incongruent. In the post-experimental interviews, participants indicated ambivalent attitudes, with references to the uncanny valley phenomenon. The following paper argues that voice-based anthropomorphization can be disrupted by artificial embodiment and inappropriate topics.