Rough Meanings: Cross-sensory correspondences linking surface textures with sound symbolism, colours, and emotions

Surface textures play a critical role in shaping interaction with tangible and multisensory technologies, yet little is known about how their microstructural features influence cognitive and affective responses - factors central to interface design. We investigated this through cross-sensory correspondences of textures systematically varying in roundness and size. Thirty participants explored 3D-printed textures under visuo-tactile and tactile-only conditions, rating them on visuo-linguistic association, roughness, colour, and emotion. Rounded textures were often linked with Bouba and pleasantness, whereas pointed textures were associated with Kiki, higher arousal, and warmer colours. Visual access also influenced exploratory behaviour, reflected in applied normal force. These findings demonstrate how microstructural tactile cues shape cross-sensory and affective associations. We propose cross-sensory correspondences as a methodological framework for designing microstructural features of surfaces textures, which could open up new design opportunities for pseudo-haptic feedback, texture-rich tangible interfaces, and coherent multisensory experiences in VR/AR.