Extended Data Fig. 1: Perceptual odor descriptors and ratings.

a, Reliability of perceptual ratings. In each subject and for each descriptor, reliability of the perceptual descriptor is computed by correlating perceptual ratings for the same odor acquired in different sessions. Gray line indicates threshold for statistical significance (r > 0.131, threshold p = 0.05, n = 3 subjects, 160 odors/subject, one tailed t-test) and dots are individual subjects. Reliability is computed between different fMRI sessions for S1. For S2 and S3, the average ratings acquired in two behavioral sessions outside the scanner were correlated with ratings acquired inside the scanner (S2, r = 0.589; S3, r = 0.660, n = 3 subjects, 160 odors/subject). The correlation of odor-wise descriptor ratings (averaged across odors) between S2 and S3 was 0.377. b, Histogram of discriminability of odors for the average subject. Discriminability between two odors is the absolute difference (in standard deviations) of the perceptual feature with maximum difference. c, Perceptual similarity matrices for all subjects. Each cell in the matrix depicts the correlation between the perceptual ratings of two odors. For illustration, rows and columns are sorted using k-means, independently for each subject. d, Generalizability of perceptual ratings across subjects is computed as the correlation between the (off-diagonal entries of) the perceptual similarity matrices of two subjects and averaged across all subject pairs (r = 0.168, p = 0.0000, n = 3 subjects, 12720 odor pairs/subject, two-tailed t-test). Dots indicate subject pairs. The gray line indicates the threshold for statistical significance (r > 0.022, threshold p = 0.05, n = 3 subjects, 12720 odor pairs/subject, two-tailed t-test). Error bars indicate 95% C.I.