Uncanny as Usability Obstacle Angela Tinwell The University of Bolton, School of Games Computing and Creative Technologies, Deane Road, Bolton, UK, BL3 5AB A.Tinwell@bolton.ac.uk Abstract. The eerie feeling attributed to photo-realistic human-like video game characters may serve as a usability obstacle leaving viewers dissatisfied with a particular character for a video game. This study investigates the relationships between user satisfaction and perceived strangeness and between user satisfaction and human-like appearance for virtual characters. 65 participants were asked to rate 13 video clips of 12 different virtual characters and one real human. The results indicate that the Uncanny Valley does serve as a usability obstacle with a strong correlation between a user’s satisfaction rating and the perceived strangeness for a character, with the characters rated the strangest being the least satisfactory. Whilst there was still a positive correlation between human-like appearance for a character with user satisfaction, this was not as significant, with stylised and anthropomorphic characters perceived to be as satisfactory or more so than those of a photo-realistic human-like appearance. Keywords: Video Games, Uncanny Valley, Photo-realistic, Usability Obstacle 1 Introduction With increasing sophistication of movement and gesture in real-time computer character animation and with improvements in the photo-realist appearance of characters, game developers are aiming to increase player engagement and the immersive experience. However there is a technical and conceptual brick wall to be overcome that is known as the ‘Uncanny Valley’. It sometimes seems that the more human-like game characters become the more vociferously potential users will object. As video games are able to approximate photo-realistic characters, will this add to the overall satisfaction for a user or act as a usability obstacle because the user becomes dissatisfied with the characters? Masahiro Mori recognised that as a robot’s appearance became more human-like it was perceived as familiar to a viewer, until finer nuances from human norms caused them to appear creepy, evoking a negative effect for the viewer. The positive relationship Mori identified between the perceived familiarity for a robot with human likeness is interrupted at certain point where the robot is perceived as more strange than familiar. This interim dip occurs at the point where the robot appears close to being human, but not fully and is referred to as the Uncanny Valley. Mori hypothesised that the Uncanny Valley would be even more exaggerated with moving characters [1].