A symmetric and an asymmetric model for the equal-sensation function in olfaction

Abstract

Data from various intramodel matehing experiments in olfaetion were analyzed with regard to asymmetrie and an asymmetrie model for the equal-sensation funetion. The asymmetrie model was diseussed in relation to the symmetrie model. In all, 11 equal-sensation funetions were investigated, and of these 9 were with different pairs of odorants. The following odorants were investigated: hydrogen sulfide, pyridine, dimethyl disulfide, and five odorants obtained by different eombustion procedures of animal manure. It was found that the equal-sensation funetion ean be written in the following asymmetric form: +i = bik A. +k bik , lf'i = lf'k or symmetrie form: I-bik bik +i = C. +k ' lf'i = lf'k, where +i and +k are stimuli expressed in multiples of respeetive absolute thresholds, Aand C are general eonstants invariant of experimental matehing method and matehed attribute (pereeived unpleasantness or intensity). The eonstants Aand C were ealculated both for group data and individual data. The asymmetrie form of the equal-sensation function was interpreted in terms of relativity and the symmetrie form in terms of measurement.