The Nudging Machine: Exploring Expressive Touch-Based Movement for Abstract Robots

A single tap from a robot can set off a cascade of interpretation. This study examines how people perceive affect, intent, and agency when a non-humanoid robot conveys meaning through contact-based nudging. Using a cube-shaped robot programmed with twenty animator-designed affect–intent variants, participants completed two tasks: a situated interaction in which the robot attempted to pass their arm, and an isolated gesture-recognition task. In the situated encounter, participants rapidly attributed motives such as attention-seeking, social contact, or boundary testing. Recognition of the robot’s obstacle-passing goal was partial but participants consistently described the robot’s movement qualities as shifting from cautious to more assertive, interpreting these changes as emotional and intentional. In the isolated task the expressive movement was far less legible: only neutral gestures were reliably recognised, with frequent confusions between comfort and attention. These findings support the position that nudging gains meaning in context: while a minimal robot can elicit rich social inference when its nudges unfold dynamically in interaction, affect and intent become opaque when the same motions are removed from their relational frame.