A possible protocognitive role for odor in human infant development.

Concepts relating to semiochemistry are now prevalent in the current literature on olfaction. Two fundamental tools of semiotics are metaphors, involving cognitive and verbal processes, and metonyms, involving nonverbal associations. By extending the concept of metonymy to non-linguistic transmission, we propose a possible explanation of how olfaction acts as a semiotic sense. Consideration of the sense of smell in animals and humans demonstrates its excellence for the formation of learned associations. In animals we find salient and complex information transmitted via biological odors. In this review, the olfactory dyadic relationship between mother and child is used for the theoretical proposal that the sense of smell plays an important protocognitive role in the genesis of cognition via mechanisms of in utero and postnatal nonlinguistic metonymic learning processes.