Hands-On or Hands-Off? Active Touch Influences Multisensory Perception of Referred Haptics

Wearable haptic devices can provide haptic feedback in both active and passive touch interactions. In virtual or extended reality environments, wearable devices also enable referred haptic feedback, where touch sensation expected in one place on the body is directed to another. How people perceive the distinction between these feedback forms has been relatively under-explored, especially considering the additional role that vision plays in our multisensory understanding of the world. To explore how active and passive touch affect the perception of referred haptic feedback, we conducted an experiment in VR where participants chose the stiffer of two springs in a 2-interval, 2-alternative forced-choice design. We find that participants can be categorized into two groups based on the different strategies they employ for making the decision - those with a haptic or a visual prior, similar to related work. We also considered both active and passive feedback conditions. Notably, people are more accurate in judging haptic stiffness during the active case. Our results have implications for designers of virtual systems and simulations where users receive various sensory inputs, both via active and passive interactions, with potential mismatches due to latency, bandwidth, or design issues.