Toward the body image horizon: How do users recognize the body of a robot?

In this study, we investigated the boundary for recognizing robots. Many anthropomorphic robots are used for interactions with users. These robots show various body forms and appearances, which are recognized by their users. This ability to recognize a variety of robotic appearances suggests that a user can recognize a wide range of imaginary body forms compared with the native human appearance. We attempted to determine the boundary for the recognition of robot appearances. On the basis of our previous studies, we hypothesized that the discrimination of robot appearances depends of the order of the parts. If the body parts of a robot are placed in order from top to bottom, the user can recognize the assembly as a robot body. We performed a human-robot experiment in which we compared the results for robots with ordered parts with those for robots with inverted parts. The result showed that the users´ perception of the robot´s body differed between the two groups. This result confirms our hypothesized boundary for the recognition of robot appearances.