The Similar Smell of Mice and Men

Whiff! readers know that our individual positive or negative reaction to a given odor is largely influenced by our own culture and personal experience. Germans, for instance, are partial to the aromas of sausage and bleu cheese but dislike that of cypress oil and fermented soybean, while the Japanese are partial to the aromas of cypress oil and fermented soybean, but dislike that of sausage and bleu cheese. Individually, we might love or detest the smell of pipe tobacco or lavender sachet, and our reaction to either, positive or negative depending on our experience, might be a vivid mental image or a simple shift in mood. But do olfactory preferences involve any innate biological characteristic? Does the chemical structure and physical properties of a given odor molecule have any bearing on what attracts us and what repulses us?

A new study into similarities between the olfactory preferences of mice and men–which share neither cultural nor, presumably, life experience–says Yes.

Nathalie Mandairon and Moustafa Bensafi, scientists in Anne Didier’s team in the Neurosciences Sensorielles, Comportement, Cognition lab of France’s Centre National de la Recherche Scientifique (CNRS), measured the olfactory responses of humans and mice to a series of odors. For the mice, the researchers used the amount of time spent exploring each given odor to index their preference. The human subjects were asked to attribute a score between 1 and 9 to each odor, with the lowest score reflecting the least pleasant.

The results? Mice and men are indeed attracted to and repelled by the same odors. The floral scent of geraniol, for instance, was the odor most preferred by both species. Conversely, the least appealing to both human and rhodent was guaiacol, an aromatic oil derived from wood creosote which corresponds to the smell of smoke.

The finding, indicating that certain base preferences are not determined by experience or culture but by the actual structure of the odorant molecule, will enable a clearer understanding of the neuronal mechanisms coding for olfactory perception, according to the CNRS team. More immediately, it may be possible to predict human olfactory preferences based on those observed in the mouse.