Ready for the Touch: Exploring Users' Perceived Transparency of Robot Pre-Touch Cues

The emergence of embodied intelligence is expending the landscape of human-robot interaction (HRI) to include more direct and physical contact. While robot touch can provide assistance or comfort, a lack of Perceived Transparency before the touch, meaning limited clarity of the robot’s intentions, can lead to user confusion and anxiety. Despite its importance for user experience, perceived transparency towards robot’s pre-touch conveyance method remains underexplored. This study systematically investigates how touch information conveyance affects perceived transparency and safety. Informed by a 340-person survey, we conducted a video-based study with 41 participants, comparing nine different robot pre-touch cues. Our mixed-methods approach combined subjective ratings and interviews with objective measures such as eye-tracking. We found that greater perceived transparency significantly enhances perceived safety. Video Displays were most effective at improving clarity, while task-oriented touch was more readily accepted than emotion-oriented touch. Based on these findings, we propose evidence-based design guidelines for safer and more effective robot touch interaction.