424 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table IX Pleasantness Rating and Sex Attribution--"Solution" Shirts Substance Sol. 2 Women (n = 29) Men (n = 30) •3 C•3 • C• Mean • mSD n Mean _+SD n Mean mSD n Mean _+SD Androstenol 1 3.44 1.19 16 2.44 1.42 13 3.05 1.40 19 2.85 1,01 2 3.42 1.27 20 2.19 1.65 9 3.43 0.62 17 2.67 1.33 3 3.84 0.84 19 3.23 1.61 10 3.54 1.03 18 3.22 0.98 4 3.96 1.03 17 4.14 1.13 12 3.37 0.89 18 3.47 1.00 5 3.93 1.02 20 3.93 1.30 9 3.56 0.94 18 3.67 0.71 III 1 3.10 1.48 13 2,65 1.33 16 2.81 1.35 12 2.78 1.15 2 3.11 1.36 12 2.80 1.31 17 2.84 0.89 15 2.73 1.28 3 3.37 0.90 21 3.67 1.30 8 3.52 1.08 22 3.83 0.64 4 3.87 1.21 21 3.54 0.96 8 3.63 1.20 17 3.03 0.67 5 3.78 1.14 21 3.58 1.10 8 3.79 1.20 21 3.59 1.19 II 1 2.29 1.56 7 q.41 1.49 22 2.97 1.75 11 1.60 1.26 2 3.22 1,44 6 1.74 1.26 23 2.87 1.43 13 1.86 1.42 3 3.30 1.41 11 2.17 1.18 18 3.20 1.69 17 2.13 1.25 4 3.28 1.28 17 2.78 1.02 12 3.72 1.18 19 2.06 1.33 5 3.22 1.13 18 3.21 0.97 11 3.11 1.07 21 2.78 0.82 CPD 1 3.82 1.49 24 4.93 0,49 5 4.10 1.30 23 3.14 1.27 2 4.04 1.25 24 4.07 1.12 5 3.70 1.09 20 3.73 1.20 3 3.96 1.19 24 3.47 0.51 5 3.88 0.86 22 3.29 1.03 4 3.58 0.95 20 3.48 1.03 9 3.53 1.34 19 3.27 1.31 5 3.95 1.14 20 3.70 0.95 9 3.54 1.13 19 3.94 0.84 1 12 12 12 18 15 8 13 9 19 17 13 11 9 7 10 8 11 11 •,2 Compare Table III. 3 Attributed to female wearer attributed to male wearer. No values were obtained for the "body" shirts due to the design of the experiment (see Table I). the test subjects: smelling 30 T-shirts in one session, five times in a row, may well have led to fatigue. However, the highly significant group trend z-scores (Table IV) for all four of the test substances, both among male and female judges, give us firm assurance that the respondents as a group were not guessing but reporting real observations.* The consideration that the respondents were given no clues that they were smelling the same materials in different dilutions gives added weight to these high z-scores. The methodology of this study does not warrant the assignment of numerical values to the slope of the psychophysical function (that is, the slope of the plot of log I versus log C) nor to the detection threshold. However, it may be sat•ly said that the study indi- cates that for all of the materials studied, both the slope and the detection threshold are very low. In the case of the highest dilutions of androstenol, II and cyclopentadecano- lide, approx. 10 -9 mole of odorant was present at each arm pit for III, the lowest tested level corresponded to about 5 x 10 -9 mole. Taking into account the low vola- tility of these substances, the concentration in the air must have been very low indeed. We have previously argued (9) that materials with a low slope of the psychophysical * We have no explanation for the curious finding that the mean intensity rating for the highest dilution of both androstenol and III (solution 5) is higher than for solution 4. The differences are non-significant.

HUMAN BODY ODOR 425 Table X Sex Attribution, Intensity, and Pleasantness x2--One sample test for intensity and sex attribution "Solution" Women X 2 = 12.8 df = 1 p .00l shirts Men X 2 = 12.8 df = 1 p .001 "Body" Women X 2 = 5.0 df = 1 p .05 shirts Men X 2 = 1.8 df = 1 p .20 x2--One sample test for pleasantness and sex attribution* "Solution" Women X 2 = 5.0 df = 1 p .05 shirts Men X 2 = 5.0 df = 1 p .05 * An analysis for the "body" shirts is not possible here due to the design of the experiment (see Table I). function and a low threshold are particularly valuable to the perfumer, because they tend to be persistent and diffusive. The low slope of the psychophysical function of androstenol, coupled with its low threshold, may well have biological, evolutionary significance. As a metabolite of a male hormone, as a substance that occurs naturally in excretions of man and other mammals, it may well have, or have had, signal function for man (1,2). For such substances, it is obviously very useful that they be perceptible at great dilutions in the air (i.e., at great distances) without becoming overpowering when smelled at far higher concentrations (i.e., from nearby). The finding that both male and female respondents rated the men's shirts, on average, higher in odor level than the women's shirts, without knowing what they were smelling, confirms Schleidt's findings (5). CONCENTRATION AND PLEASANTNESS The negative correlation between concentration and pleasantness for androstenone, II, and III is in line with perfumers' common experience regarding "animal" odorants (civet, natural musk, indol, and others): that they must be used sparingly and lead to rejection if used at too high levels (compare also references 2 and 4). The synthetic musk, cyclopentadecanolide, does not exhibit this behavior at all. In a qualitative sense as well, cyclopentadecanolide was found to be considerably further removed from actual human body odor than are the other odorants tested numerous respondents remarked that the shirts with cyclopentadecanolide smelled "perfumed." An interesting incidental finding was the wide variability in pleasantness ratings for the T-shirts that had actually been worn. Both for shirts worn by women and those worn by men, and both with female and with male respondents, the difference between the shirt judged most pleasant and the one judged least pleasant was significant (Table XI)--but more highly for men's than for women's shirts. PERCEIVED INTENSITY AND PLEASANTNESS The finding that the correlations between perceived intensity and pleasantness (Table