Experimental protocols used in tactile perception of materials: a mini review

Tactile perception plays a central role in how humans evaluate and interact with materials, influencing perceived roughness, softness, friction, warmth, wetness, comfort, quality, and usability. In recent years, experimental studies on tactile perception have expanded across diverse material systems, including textiles, synthetic fibers, plastics, wood, building materials, soft rubbers, textured surfaces, and haptic overlays. However, the experimental protocols used across these studies remain highly varied. This mini-review examines recent experimental approaches adopted in tactile perception studies of materials, with emphasis on work published within approximately the last 5 years. We identified common methodological strategies, including psychophysical rating scales, forced-choice and pairwise-comparison tasks, tactile-only and visual-tactile testing, active-touch standardization, instrumented material characterization, and multisensory or haptic-interface protocols. By comparing these approaches, the review highlights how differences in material selection, sensory access, exploratory movement, subjective rating methods, and physical characterization influence the interpretation of tactile perception data. We also discuss key research gaps, including the need for standardized reporting, cross-material benchmark datasets, diverse participant populations, improved control of touch behavior, and stronger links between tactile perception experiments and material-design guidelines.