Touching a Cat Without Touch: Does Mid-Air Ultrasound Haptic Feedback Promote Relaxation in Virtual Cat Interaction?

Human–animal interaction in virtual reality has been explored for stress relief, yet balancing practical ease of use with natural haptic experience for relaxation remains a key challenge. We investigated whether mid-air ultrasound haptics, rendering breathing and fur stroking cues without wearable haptic devices, could enhance relaxation with a virtual cat. We first conducted a perceptual study to design a tactile cue for a cat’s breathing. By synchronizing expansion–contraction of the ultrasound focal region with intensity modulation, we demonstrated the realism and expressivity of the breathing cue. Next, we conducted an application study in which participants engaged in a short relaxation session with a virtual cat. Physiological and subjective measures showed that ultrasound haptics enhanced relaxation compared to both non-haptic interaction and controller-based vibrotactile feedback. These findings suggest that ultrasound haptics can extend VR-based human–animal interaction by combining accessibility with psychological benefits, opening new opportunities for well-being and therapeutic applications.