MEASURING THE MEANING OF FRAGRANCE 765 of the adjectives the experimenter has provided. The experimenter will make every effort to select adjectives which will cover all aspects and all dimensions of the odor which may be relevant to the respondent, but he can never be sure that he has succeeded in this. Also, the adjectives or word-pairs used in the questionnaire may introduce distortions by in- fluencing the respondent, e.g., by suggesting that certain things are rele- vant which are actually of no importance to him. In the multidimen- sional scaling technique, the respondent is given no words. He judges differences and similarities between odors along dimensions which he may not even consciously formulate but which are, ipso facto, the most relevant to him. It is for this reason that those who have set out to ex- plore olfaction without preconceived ideas, in search of primary odor qualities, have preferred to use multidimensional scaling.* Woskow (11) used odorants and described them in a nine-dimensional space of which the first three dimensions were the most important. Al- though the dimensions are not labeled, their meaning can be interpreted by looking at what odorants lie close to the ends of the space along each of the dimensions. Woskow's first and mathematically most important dimension (it accounted for a large portion of the differences between the odorants) was clearly an evaluative one. It had vanillin, safrol, methyl salicylate, and benzaldehyde at one end and butyric acid, pyri- dine, and scatol at the other. The second dimension has camphor, guaiacol, and menthol at one end and aliphatic alcohols (C2-C•) and vanillin at the other. Woskow suggests the label cooling, woodsy for this axis but prickling-medicinal vs. soothing-unctuous might be prefer- able. The third and following dimensions are difficult to interpret. In fact, in interpreting a multidimensional model, a good case can be made for not assigning any meaning to dimensions but only to interpoint dis- tances. Schutz, also trying to uncover primary odors, measured the quality of 30 odorants using both a semantic differential technique and multidi- mensional scaling (12). From the multidimensional scaling experiment he derived nine main factors which he labeled: fragrant, etherish, sweet, burnt, rancid, oily, metallic, spicy, and sulfurous or goaty. On the basis of this work, Schutz proposed a nonverbal method of describing odors: choose some standard odors which are distinctly dif- ferent from one another for each odor to be described, have respondents * Even using this technique the experimenter cannot help influencing the outcome of his experiment: he is the one who selects the odorants to be tested, and he has to interpret the results.

766 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS judge the pair-wise distances (degrees of difference) between this odor and each of the standard odors use a group of respondents and average their judgments to get reproducible values. The set of average distance judgments of the new odor with respect to the standard odor describes, and in a sense, defines the new odor. Schutz used nine odorants, one for each of his factors, as standards, but other standards may also be used with this method which Schutz called the "matching standards method." Amoore (13) has applied the matching standards method to test his own theory about primary odors. Yoshida (14) also examined a divergent group of odorants by the multidimensional scaling technique in an attempt to ascertain whether earlier proposed schemes for odor classification had any objective basis. He also investigated a group of modern luxury perfumes and a group of spices and herbs by the same technique. In each case, he extracted four or five factors, of which the evaluative one was the most important one. So far, then, attempts to find primary odors as the underlying dimen- sions in a multidimensional space model of odor have only been moder- ately successful. They have, however, shown that multidimensional scaling can be used to construct space models of odors. We can then use these models for different purposes, i.e., to measure how consumers at large react to given fragrances, in what way and in what direction a change in a fragrance affects the consumers' perception of it, or to get guidance in the development of new fragrances for a specific purpose.* True, the lack of words in the model to guide us can become a handicap, but there are ways of overcoming this difficulty. A research group at General Foods is currently using a modified multidimensional scaling technique in flavor work with very promising results. PRODUCT TESTING The new techniques for measuring the relations between, and the meaning of things and concepts in general, and of fragrances in particu- lar, can be of real value not only to the perfumer, but also to those in the perfumery and cosmetic industry who are concerned with the con- sumer testing of new or improved products. As Randebrock (8) pointed out, the use of a questionnaire containing many different scales (29 in his case), rather than only questions about degree of liking or preference has the advantage of yielding stable, reproducible results with panels of as few as 30 respondents whereas the traditional tests require several * A novel technique of new product development which makes extensive use of multi- dimensional scaling is described by Barnett (15).