Fig. 4

Perception of stimuli. a Histograms of intensity ratings for the five most intense of 437 stimuli presented at 1/1000 dilution (most intense on top). b Average intensity ratings of 437 molecules presented at 1/1000 and 1/100,000 dilutions, with standard error of the mean shown for two molecules [methyl salicylate (green) and methyl caprylate (blue)]. The intensity rating of water (14.44) is indicated by the blue shading. c, d The ten most pleasant (most pleasant on top) (c) and ten least pleasant of the 1000 stimuli (least pleasant on bottom) (d). e Descriptor rating of the stimuli most representative of each of the 20 descriptors. Individual ratings as well averages and standard errors (in red) are shown. Only the 778 stimuli perceived to be more intense than water (14.44) were included in this analysis. In a, c, d Histograms of subject ratings of intensity a or pleasantness c, d are plotted on a scale from 0–100, binned in 20 units of 5