RoboBunting: Building Social, Affective Expressiveness through Bilateral Force Exchange

Abstract: We propose that social robots able to interact in a “bidirectionally physical” manner, by continuously modulating their own movement and impedance in a direct coupling with the user's rather than simply triggering pre-set physical responses, have high potential for social expressiveness and durable engagement. This study explores how the dynamics of robot bunting, a feline behavior involving playful, affective force exchanges, can influence user perception of robot Personality Attributes ( e.g., extroversion and openness) and Interaction Qualities ( e.g., intentionality, liveliness, aliveness). With a minimalist one-degree-of-freedom (1-DF) haptic display, we created a control architecture to portray an abstract zoomorphic creature and conducted a user study (N=14) to evaluate the effects of Robot Role ( Leader or Follower ) and three Physical Dynamics variables (rendered stiffness, motion frequency and time delay). Participants stroked, scratched and petted the robot under each robot condition and reported on their social perceptions of it. Varying Robot Role significantly impacted attributes in both groups, while Physical Dynamics influence was concentrated on Interaction Qualities. Physical Dynamics factor variables behaved differently in each Role; e.g., when the robot was a Leader , high stiffness enhanced perceptions of intentionality and high motion frequency conveyed liveliness, while as a Follower , increased stiffness and delay raised user impressions of aliveness. This research demonstrates how physical qualities can shape human social perceptions of even a simple, abstract robot and that their subtle adjustment can create a wide range of social manifestations, with implications for generating sustained human-robot engagement.