The five most fundamental tastes are sweet, sour, bitter, salty, and umami (savory). Probably sweet taste is the most pleasant out of all the basic tastes (Beauchamp 1987). Considering about the multisensory communications, sensing and actuating taste digitally is an extremely important requirement. Once we reached that goal people will be able to experience the taste digitally across the internet as we experience text, audio and visuals online. The early sweet taste interfaces developed in the field of Human-Computer Interaction have primarily used chemicals to generate taste sensations (Kortum 2008, Maynes-Aminzade 2005, Tutton 2008). However, some recent works have identified that thermal stimulation can evoke sweet sensations on the tongue. This is achieved by triggering the TRPM 5 channel (Transient receptor potential cation channel subfamily M member 5). In previous experiments raising the temperature on the tongue within few seconds has reported sweet sensations for a subset of the participants (Cruz and Green 2000), while high temperatures resulted enhancing the sensitivity for sweetness in some other studies (Talavera 2005, Green 2015).
Using this concept, we developed a computer driven user interface that change the temperature on the tongue surface rapidly and currently we are exploring the ways to produce sweet taste sensations digitally in repeatable and controllable manner using this interface. By placing the device on top of the tongue will results a slight modification of the temperature from 25˚C to 40˚C on the tongue surface and we have observed that some subjects reported sweetness while some are reporting the enhancement of sweetness. However, on border perspective we believe this technology can stimulate different type of taste receptors on the tongue. Therefore, we are currently conducting an experiment that study how this technology could create or modify taste experiences virtually. We believe by continuously improving this technology we may be able to create, enhance, and share virtual taste experiences.