Visuo-haptic exploration with relocated haptic feedback: impact of virtual and augmented reality

Rendering haptic feedback on the wrist is an effective solution for freeing users' hands during virtual interactions while still providing haptic feedback, mostly focusing on Virtual Reality (VR) environments. Unfortunately, whether these solutions can be extended to Augmented Reality (AR) interactions has not been investigated before. In this paper, we investigate the perceptual differences between VR and AR environments with a user study experiment based on a stiffness discrimination task. Our findings revealed similar task accuracy and sensitivity in VR and AR but different exploration behaviors (i.e. higher interaction time in AR) and user experience (i.e. higher enjoyment and less mental fatigue in AR). These differences may be explained by the increased cognitive load and the environmental immersion in AR, where users navigate both virtual and real elements simultaneously. This suggests that visuo-haptic psychophysical findings obtained in VR can be extended to AR, even though user experience and exploration behavior might differ.