Olfactory Displays - Olfactory System

Of all of our senses, the sense of smell or olfactory system and its concomitant taste or gustatory sense, are the least used in information displays. Taste is generally considered inappropriate for information displays as substances must be placed in the mouth or on the tongue to activate this sense. Both taste and smell are chemically reactive senses. Smell is based on the inhalation, binding, and processing of airborne odor molecules. Taste is based on contact with and processing of molecules in aqueous/water solution. What we think of as our sense of "taste" is really comprised mostly of our sense of smell. Taste is limited to: sweet, sour, bitter. salty, and umami (glutamate).

Smell is a chemical sense. Vision and hearing are the result of detection and processing of energy waves in the form of light and sound waves, respectively. Smell is the detection and processing of airborne chemical molecles. Because of the wide variability of these molecules in composition and shape, it has not been possible to develop a "smell scale" analogous to those of light wavelengths for vision and sound pressure levels for hearing.

We can detect over 10,000 scents and can identify some odors in concentrations as small as one part per billion. Our sense of smell has evolved as an important "survival" cue that warns us of changes in our environment such as the presence of fire. It also warns us of characteristics of food that could signal poisoning such as a strange or rotten odor. Smell is also a potent memory stimulus that can evoke strong emotional response.

Image copyrighted by A.D.A.M. Used by special permission of the National Library of Medicine (NLM).