Effect of Interference on Multi-Sensory Haptic Perception of Stretch and Squeeze

Multi-sensory haptic systems have the potential to transfer a wide variety of information to a human user by delivering multiple types of haptic cues simultaneously. However, these systems may cause undesirable perceptual interference, which has already been observed in wearable systems that simultaneously convey skin stretch and squeeze cues. To investigate this observed perceptual interference, we conducted a psychophysical evaluation of the just-noticeable difference (JND) in skin stretch and squeeze cue magnitudes independently as well as in the presence of an interfering cue. A haptic testbed delivered each cue to a user's proximal forearm. First, the JNDs of the two haptic cues were each measured alone. Then, the cues were delivered simultaneously and the JND values for stretch with squeeze interference and squeeze with stretch interference were measured. We found that the JND for the stretch cue increased with the addition of an interference squeeze cue, while the JND for the squeeze cue did not change with interference. Results suggest that there is an interference effect between multi-sensory haptic cues that, depending on cue type, can negatively impact haptic perception. Further development of multi-sensory devices that convey salient cues has the potential to mitigate this observed interference.