On the evaluation of emotion expressing robots

Common works on emotion expressing robots are theoretically based on a dimensional (continuous) model of emotions. Nevertheless, performance tests, which are used to evaluate the emotion expressing robots, are based on categorical (discrete) models of emotions. In this paper the use of dimensional-based tests is suggested, e.g. semantic differential approaches like the Pleasure-Arousal-Dominance-Model. By deriving the test from the theory on which the design of an object is based, the validity of the test raises significantly. Major benefits are explicit guidelines for design improvement and the possible integration of arbitratry actuated expressive features for which no common framework as e.g. the Facial Action Coding System (FACS) exists. For illustration purposes, a comparative evaluation study of the robot EDDIE is conducted: one test is based on a categorical model and one test is based on a dimensional model of emotion. A third study based on a dimensional model demonstrates the evaluation of the influence of animallike features on the perceived emotion state.