Demographic differences in perceived odour quality. a, Colour code for the categories of descriptors used. b, g, l, The molecular structure of androstenone (b), pentadecalactone (g), and vanillin (l) and the frequency with which descriptors were applied to each odour are shown. Only descriptors that were used in at least 10% of the visits are shown. The frequency of descriptor usage is represented by the area of the rectangles. c-f, h-k, m-p, The percentage differences between demographic groups in descriptor usage for descriptors that were applied to androstenone (1/10,000 dilution) (c-f), pentadecalactone (1/500 dilution) (h-k), or vanillin (1/200 dilution) (m-p) in more than 10% of the visits (Ns: < 35 years: 195; > 35 years: 196; Women: 210; Men: 181; Asians: 31; African-Americans: 97; Caucasians: 178). Subjects were divided by age according to the median of 34.6 years, which is rounded to 35 years for labeling the figure.