The Uncanny Effect of Speech : the Impact of Appearance and Speaking on Impression Formation in Human–Robot Interactions

This study explores the impact of appearance and speech on human perceptions of faces in human- robot interactions. Three videos were generated depicting the real face of an artist and two virtual versions of the same artist, with increasing resolution and fidelity. Each video was presented with and without speech, with matching levels of fidelity to the faces (real human speech and machine- generated speech of two levels of realism). Participants viewed all six videos and rated them on measures such as convincing, trustworthy, realistic, likable, showed biological movement, reassuring, friendly, familiar, and humanness. We found that the inclusion of speech (real) had a significant positive impact on the impression formation of real human appearance. In contrast, perceptions of the virtual avatars were more negative when speech (machine-like) was incorporated. This study illustrates the differential effects that speech can have on virtual faces in interactive settings.