Improvement of perceived stiffness using auditory stimuli in haptic virtual reality

This paper describes a psychophysical experimental study to determinate whether time duration auditory information may improve the haptic perception of surface stiffness in a virtual environment (VE). In the experiment, the subjects were given the task of deciding which of two virtual surfaces is the stiffer one, via PHANToM, a haptic force feedback device, and displayed on a computer screen. They must tap both surfaces only one time and every time a surface is tapped, an auditory stimulus, synchronized with the tap, is played. Results indicate that auditory stimuli interfere on stiffness haptic perception. It showed that stiffness-duration factors interaction significantly influences on stiffness perception. We found that the subjects perceive coherence between auditory and haptic stimuli when shorter auditory stimuli are associated with stiffer haptic stimuli and vice versa. In case of non-coherence (stiffer surfaces associated to longer auditory stimuli and vice versa), the auditory stimulus misleads the subject providing a negative effect in the task of discerning the stiffer surface. Designers of VEs could use these results for improving stiffness haptic perception of virtual objects