Roughness is studied by examining how textures are perceived and encoded by an individual's somatosensory system. In an experiment to measure and compare the roughness of different sounds, listeners are presented with different sounds and asked to rate their roughness, for example on a
rating scale. Recent research has displayed that there are two different codes, at least, for roughness: a vibrotactile code used for fine surfaces, and a spatial code used for coarse to medium surfaces.