ODOR CLASSIFICATION Degree of Appropriateness 1 2 3 4 5 6 7 exciting • soothing weak strong •'"•"•i• • :2-....• active passive f.., friendly J ,.•? aggressive loud • soft ""' '• full empty •. '" beautif ul • ..... ugly stern • I "%X mild depressing '• exalting dull •--' • biting 519 -- = Amber o. ........ -o = Ideal erogenous fragrance Figure 3. Partial profiles of amber and of "the ideal erogenous fragrance" ferential" method described by Osgood (7) adapted to the specific de- mands of odor description). It was first employed in the study re- ported by the author in Munich in 1960 (3). The heart of this procedure is a list of 29 pairs of adjectives the two members of each pair are opposite in meaning.* Thirty judges were * This list was obtained from an original list of 40 word pairs by eliminating those which, by use of the statistical "t-test," were found not to distinguish significantly between different odors.

520 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS asked to describe the odor of amber in terms of this list. Thus for the first word pair they expressed their opinion that amber is more ex- citing than soothing, in the seventh they found it more ugly than beautiful and so on down the line with all the other word pairs. Figure 2 shows the average of the 30 judgments on each word pair. The pro- file which is obtained in this way is typical for amber. It is, moreover, reproducible. The correlation between profiles obtained for amber at I ACTIVITY* I abs. 0,5'/• Castoreum Civet ACTIVITY- I Figure 4. Odor description space with 11 "erogenous" odors different occasions and by different judges lies between +0.87 and + 0.94 the statistician knows that this is excellent. One of the advantages of this method is that it can be used also to get a picture of concepts or mental images which have no physical reality. Thus 30 persons, who had first been asked about amber, were asked to imagine that fragrance which would most closely approximate their idea of erogenous and to describe it using the semantic differential. The resulting profile has been partially reproduced in Fig. 3 clearly it is very sharp and characteristic. It now becomes possible to compare the profile of amber or of any other fragrance with this "ideal" profile.