Effect of physical properties of fabric under cold dry stimulation on wetness illusion

People can perceive wetness when they touch a cold dry surface, a phenomenon known as the wetness illusion. Most previous studies of the effect of fabric physical properties on wetness perception have been focused on wetted fabrics. However, since water affects a fabric’s physical and heat transfer properties, it is difficult to fully understand the true mechanism of a fabric’s physical properties on wetness perception. Twelve young female participants were recruited to touch the fabrics with their index fingers and assess wetness perception in two experiments. This study is an investigation of the effect of a fabric’s physical properties on wetness perception from two perspectives: surface properties (roughness) and compression properties (softness). In Experiment 1, participants horizontally touched nine dry fabrics with varying roughness and maximum transient thermal flux at three surface temperatures (10°C, 13°C, and 16°C), maintaining a constant velocity, and rated both roughness and wetness perceptions. In Experiment 2, participants vertically pressed nine dry fabrics with varying softness and maximum transient heat flux at the same three surface temperatures (10°C, 13°C, and 16°C), applying constant pressure, and rated both softness and wetness perceptions. The results demonstrate that fabric roughness was negatively correlated with wetness perception, and softness was similarly and negatively correlated with wetness perception. However, regression analysis identified neither roughness nor softness as the primary predictor of wetness perception, whereas maximum transient thermal flux emerged as the primary predictor. We conclude that the effect of fabric surface roughness and softness on wetness perception is primarily attributed to an association with thermal conductivity.