Electronic noses (eNoses) are typically tuned to identify particular odorants, ranging from "cocaine" to "spoiled milk". In contrast, here an eNose was tuned to the perceptual axis of odorant pleasantness, i.e., an axis ranging from very pleasant (e.g., rose) to very unpleasant (e.g., skunk). This allowed the eNose to then smell novel odorants it never encountered before, yet still generate odor pleasantness estimates in high agreement with human assessments regardless of the subject's cultural background. This suggests an innate component of odorant pleasantness that is tightly linked to molecular structure (see Haddad et al., doi:10.1371/journal.pcbi.1000740).

Image Credit: Genia Brodsky and Noam Sobel (The Weizmann Institute)