Does Synthetic Voice alter Social Response to a Photorealistic Character in Virtual Reality?

In this paper, we investigate the effect of a realism mismatch in the voice and appearance of a photorealistic virtual character in virtual reality. While many studies have investigated voice attributes for robots, not much is known about the effect voice naturalness has on the perception of realistic virtual characters. We conducted an experiment in Virtual Reality (VR) with over two hundred participants investigating the mismatch between realistic appearance and unrealistic voice on the feeling of presence, and the emotional response of the user to the character expressing a strong negative emotion (sadness, guilt). We predicted that the mismatched voice would lower social presence and cause users to have a negative emotional reaction and feelings of discomfort towards the character. We found that the concern for the virtual character was indeed altered by the unnatural voice, though interestingly it did not affect social presence.