Figure 1

Results of the tactile task and associative learning sessions. Similarity matrices were computed based on the estimated difference of perceived roughness intensities between each pair of sandpapers (a) without and (b) with visual cues. These matrices were significantly correlated (r = 0.975, p < 0.001), suggesting that perceived roughness intensities were similar regardless of visual information. (c) The relative positions of five roughness intensities depicted in a 2-dimensional MDS map.