Tactile flow on seat pan modulates perceived forward velocity

We conducted a user study to clarify whether a tactile flow created by a matrix of vibrators in a seat pan simultaneously presented with an optical flow in peripheral vision enhances the perceived forward velocity of self-motion. A brief tactile motion stimulus consisted of four successive rows of vibration, and the inter-stimulus onset between the tactile rows was varied to change the velocity of the tactile motion. The experimental results show that the forward velocity of self-motion is significantly overestimated for rapid tactile flows and underestimated for slow ones, compared with only optical flow or non-motion vibrotactile stimulation conditions. Furthermore, the tactile flow on the seat pan can be applied in a car-racing computer game and provide a perceptual change in forward velocity.