Feeling Illusory Textures Through a Hole: Rotating Frame At Skin-Object Interface Modifies Perceived Tactile Texture

Modulating tactile texture perception for the surface of real objects is a promising way to artificially present various tactile textures. Here, we propose a simple method of modulating tactile textures for various materials, which is named the rotating-frame method. In the method, one touches an arbitrary material's surface through a hole in a cardboard frame. When the frame is rotated between the hand and material, the tactile texture of the material is perceived as if it has turned into another material. We investigated the qualitative and quantitative characteristics of the illusory modulation created by the method in a series of psychophysical experiments. We found that the method altered the tactile textures of the surfaces of touched materials such as glass and carpet to seem softer, smoother, slipperier, and warmer than they actually are. The illusory texture change occurred robustly when the method was applied with different categories of materials. Our method paves the way for the development of simple techniques for texture augmentation that can be applied to a wide range of materials and do not disrupt stable direct contact between the hand and the materials.