Fig. 1. Uncanny valley of haptics. (A) The theoretical uncanny valley of haptics as defined by studies from the classic humanoid robotic uncanny valley (1). (B) The empirical data from our experiments. The subjective experience corresponds to the Presence Questionnaire score. (C) A diagram showing the stimulation paradigm for producing the illusion of spatialized haptic feedback via funneling. In generic haptics stimulations, the same amplitude of vibrations was delivered for all trials to both controllers. No funneling occurs in such conditions. However, under the spatialized and visual + spatialized conditions, a funneling effect was achieved by varying the vibrotactile amplitude delivered at each controller, producing a change in the perceived haptic location. (D) Inside the VR headset, the participant sees a (virtual) wooden dowel that bridges their hands (as sensed by the position and orientation of the controllers). In the passive and causal experiments, the participant held the dowel in a specific “activation area” to receive the haptic stimuli (represented by a “cloud” that looked like a smoky cylinder). During the visual + spatialized stimulation, participants saw a white marble cue that visually reinforced the location of the haptic feedback.
The 'uncanny valley' of haptics in Virtual Reality
Our sense of touch is a crucial part of how we engage with the world around us and perform manual tasks. This is also true for teleoperation and virtual environments, and researchers and engineers are therefore beginning to make great strides in improving the haptic experiences in these domains. However, as in the case of humanoid-robotics where increased realism of human-like robots leads to feelings of unease or revulsion often represented by an ‘uncanny valley’ of our subjective experience of them, it may also be the case that as our haptic experience in these environments improves, it can reduce the subjective realism of the haptic experience as the visual environment fails to keep up with the improved haptics. In this study, we show that there is an uncanny valley of haptics, whereby enhanced haptic feedback in virtual environments improves one's subjective experience up to a point, but then decreases dramatically when the virtual environment fails to keep up with the increased expectations from the enhanced haptic experience. Our findings provide important insights for the rendering haptics in multi-modal scenarios that may benefit many real-world applications, including teleoperation scenarios, remote robotic manipulation, or tele-operation tasks, for example. Click here to read our article published in Science Robotics. Click here to read a popular science version of our article published in Scientific American.
Paper Title: The Uncanny Valley of Haptics
One Sentence Summary: During virtual experiences, enhanced haptic feedback incongruent with other sensory cues can reduce subjective realism.