Illusion of Wetness by Dynamic Touch.

Abstract

Humans perceive wetness on contact with a dry-cold material; however, the magnitude of wetness that can be perceived using dynamic touch remains unclear. This study assessed how the type of touch, namely hand movement (either statically or dynamically) and pressing force (either low or high pressure), affect the perception of wetness. The participants judged the magnitude of perceived wetness after four types of touch of four stimuli comprising four fabrics of varying water content and surface temperatures. Overall, the perceived wetness was differed between static and dynamic touch independent of pressure and the participants scored the dry-cold stimulus as relatively dry for dynamic touch. Furthermore, cluster analysis revealed individual differences in the recognition of wetness in dynamic touch conditions. These results revealed the variability in the mechanisms used by humans to perceive wetness. Additionally, we discussed the optimal methods to reproduce the wetness perception using this illusion.