Physicochemical influence on odor hedonics: Where does it occur first?

We recently reported data showing that, while human olfactory pleasantness is modulated by semantic knowledge of smells, the physicochemical aspects of odorant molecules are prominent determinants of odor hedonic valence, especially in children and seniors, two age groups characterized by either low level of (children) or weak access to (seniors) odor semantic knowledge.1 Here, we present additional data from a human and an animal study, confirming that odorant structure predicts odor pleasantness and suggesting that this influence may be already engraved at receptor level.