The Uncanny Valley Effect in Zoomorphic Robots: The U-Shaped Relation Between Animal Likeness and Likeability

The uncanny valley effect denotes a dip in the positive relation between a robot’s human likeness and likeability. This paper provides first evidence that this design-guiding effect is not limited to humanoids, but extends to zoomorphic robots. In a first online survey, a diverse group of 235 participants rated the animal likeness of 140 robots. Three predictors for high or low animal likeness emerged: surface properties, such as joint visibility; facial properties, such as presence of a pupil; animal-specific properties, such as presence of snout. In a second online survey, 187 participants rated the likeability of 53 robots of varying degrees of animal likeness drawn from the first study. The relation between animal likeness and likeability followed a U-shaped function and showed an uncanny valley effect: robots high and low in animal likeness were preferred over those mixing realistic and unrealistic features. Besides theoretical implications tentative guidelines for the design of zoomorphic robots are discussed. Acm Reference Format: Diana Löffler, Judith Dörrenbächer and Marc Hassenzahl. 2020. The Uncanny Valley Effect in Zoomorphic Robots: The U-Shaped Relation between Animal Likeness and Likeability. In Proceedings of the 2020 ACM/IEEE International Conference on Human-Robot Interaction (HRI’20), March 23–26, 2020, Cambridge, UK. ACM, New York, NY, USA, 10 pages. https://doi.org/10.1145/3319502.3374788