“You Scare Me”: The Effects of Humanoid Robot Appearance, Emotion, and Interaction Skills on Uncanny Valley Phenomenon

This study investigates the effects of humanoid robot appearance, emotional expression, and interaction skills on the uncanny valley phenomenon among university students using the social humanoid robot (SHR) Ameca. Two fundamental studies were conducted within a university setting: Study 1 assessed student expectations of SHRs in a hallway environment, emphasizing the need for robots to integrate seamlessly and engage effectively in social interactions; Study 2 compared the humanlikeness of three humanoid robots, ROMAN, ROBIN, and EMAH (employing the EMAH robotic system implemented on Ameca). The initial findings from corridor interactions highlighted a diverse range of human responses, from engagement and curiosity to indifference and unease. Additionally, the online survey revealed significant insights into expected non-verbal communication skills, continuous learning, and comfort levels during hallway conversations with robots. Notably, certain humanoid robots evoked stronger emotional reactions, hinting at varying degrees of humanlikeness and the influence of interaction quality. The EMAH system was frequently ranked as most humanlike before the study, while post-study perceptions indicated a shift, with EMAH and ROMAN showing significant changes in perceived humanlikeness, suggesting a re-evaluation by participants influenced by their interactive experiences. This research advances our understanding of the uncanny valley phenomenon and the role of humanoid design in enhancing human–robot interaction, marking the first direct comparison between the most advanced, humanlike research robots.