In this chapter, the authors introduce interaction of olfaction with other senses by showing two different types of case studies based on this interaction. Olfactory sensation is based on chemical signals whereas the visual sensation and auditory sensation are based on physical signals. By using this cross-modal effect between olfaction and vision, olfactory display can present various “pseudo olfactory experiences.” One can produce an olfactory sensation different from the presented smell. In addition, by using cross-modal effect among olfaction, gustation, and vision, one can present various “pseudo gustatory experiences” with the same food via visual-olfactory displays. By utilizing the interaction of olfaction with other senses, it is possible to augment the capability of olfactory displays and achieve a high quality olfaction and gustation experience.
Olfactory And Gustatory Displays
Both olfactory and gustatory senses have instability different from the other senses. The new concept mentioned above can be applicable when implementing olfactory and gustatory displays.
Among five senses, it is said that olfaction activates our emotion most vividly. Therefore, it would be effective to use olfactory system as communication media. Olfaction is more unstable and variable than vision and audition. It is known that we can identify scents of daily materials only fifty percent of the time. For example, only half can answer “apple” when they sniff apples (Cain, 1979; Sugiyama, Kanamura, & Kikuchi, 2006).
Although olfactory displays are uncommon, many researchers are working to develop ways to display scents (e.g., Nakamoto & Minh, 2007; Yamada, Yokoyama, Tanikawa, Hirota, & Hirose, 2006; Nakaizumi, Yanagida, Noma, & Hosaka, 2006; Sato, Ohtsu, Bannai, & Okada, 2008). Moreover, some olfactory displays using vaporizers have already been commercialized (e.g., ScentAir; AromaJet; Trisenx; Scentcommunication; Osmooze; air aroma; Air/Q Whole Room Air Freshener). These display systems are used for appreciations with combination of other sensory displays (Heilig, 1992; Zybura & Eskeland, 1999; Mochizuki, Amada, Sawa, Takeda, Motoyashiki, Kohyama, … Chihara, 2004). For example, “Let’s cook curry” developed by Nakamoto, Otaguro, Kinoshita, Nagahama, Ohinishi, and Ishida (2008) is an olfactory display with interactive aroma contents, “a cooking game with smells.” It presents smells of curry, meat, onion and so on by player’s control. “Wearable olfactory display” developed by Yamada, Yokoyama, Tanikawa, Hirota, and Hirose (2006) generates a olfactory field by changing concentration of some kinds of aroma chemicals using position information.
However, both of them produced only combination of prepared element odors, they are, selected aroma chemicals, in each preceding studies. It is still difficult to generate infinite numbers of smells for current olfactory displays.
A gustatory display would be one of the last frontiers in the area of computer human interaction. Even comparing with the olfactory displays, very few studies are conducted regarding as this area.