1 Kinematics of Unconstrained Tactile Texture Exploration 2 3

16 A hallmark of tactile texture exploration is that it involves movement between skin and surface. When 17 we scan a surface, small texture-specific vibrations are produced in the skin, and specialized cutaneous 18 mechanoreceptors convert these vibrations into highly repeatable, precise, and informative temporal 19 spiking patterns in tactile afferents. Both texture-elicited vibrations and afferent responses are highly 20 dependent on exploratory kinematics, however; indeed, these dilate or contract systematically with 21 decreases or increases in scanning speed, respectively. These profound changes in the peripheral 22 response that accompany changes in scanning speed and other parameters of texture scanning raise the 23 question as to whether exploratory behaviors change depending on what surface is explored or what 24 information is sought about that surface. To address this question, we measure and analyze the 25 kinematics as subjects explore textured surfaces to evaluate different types of texture information, 26 namely the textures' roughness, hardness, and slipperiness. We find that the exploratory movements 27 are dependent on both the perceptual task, as has been previously shown, but also on the texture that 28 is scanned. We discuss the implications of our findings regarding the neural coding and perception of 29 texture. 30