For decades, researchers have been intrigued by man’s ability to integrate sensory information from a large number of chemicals into a single smell perception. The aroma of a strawberry or an apple, the fragrance of an exotic perfume, or the horrendous stench which emanates from a sewer, all of which seem singularly unique, in reaIity comprise many dozens, hundreds, or even thousands of different chemicals. Their interaction, and the instantaneous registration of these components in our conscious perception produce the unitary impression.
What is even more remarkable about this world of odor mixture is the continuing integrity of quality perception in the face of changes in the chemical constitution of the substances from which the smell emanates. An assortment of different apple varieties (e.g., Cortland, Winesap, and Delicious) will exhibit a set of entirely different gas chromatographic tracings showing varying chemicals at varying concentrations. Somehow, the brain manages to register all of these mixtures of chemicals as apples, albeit apples of different varieties.
This report is concerned with research efforts on odor-mixture perception. In most of the studies reported here investigators systematically mixed together two (or perhaps a larger but still manageable number of) chemicals in a limited range of concentrations, rather than trying to imitate nature in her mélange of ingredients. Two major aspects of odor mixture, the perception of odor intensity in these mixtures and the perception of odor hedonics, are discussed.
