Mugginess sensation: Exploring its principle and prototype design

Recent haptic technologies represent not only geometrical and mechanical properties of virtual objects, e.g. shape, softness, and natural frequency, but also thermal and other non-contact sensations such as hotness and wetness. However, the techniques that artificially display spatial humidity like mugginess in highly humid weather have not been explored. In this study, we provide the first comprehensive investigations on mugginess sensations and prototype mugginess displays, including their cross-modal impact on temperature sensations. Our experimental results revealed that highly humid air was felt warmer than normal room air of the similar or even higher temperature when the hand was placed in a plastic container. It is considered that the warmness was felt due to more liquefaction and less vaporization between vapor in the air and water droplets on skin surface. We designed a prototype mugginess display which can quickly control the humidity by using constant humid airflow and an exhaust fan. We then conducted threshold investigation of humidity on daily exposed body parts; cheek, neck, and wrist, among which cheek was found to be the most sensitive. The results obtained in this study will expand the potential of haptic technologies and open up new possibilities of mugginess displays.