More on the sense of smell

Now Smell This linked to an interesting article today on Yahoo News titled Super Sense of Smell Not Innate (by Marlowe Hood on Wed March 9). The article discusses how perfumers gain much of their ability to detect and identify scents through years of training and experience rather than being born with these skills. The article also mentions an ongoing theme we’ve discussed here concerning the differences in the way people experience the same scents (for more, see other posts under the blog’s Olfaction category).

An excerpt from the Yahoo News article:

“Patrick MacLeod, former head of the Laboratory for Sensorial Neurobiology, near Versailles, says that olfactory thresholds vary dramatically.

“No two people will ever smell the same thing in the same way,” he noted. “When we perceive an odour the exact nature of the sensation that is produced depends as much on the observer as the object.”

In experiments, he has shown that a small quantity of a given molecule may be imperceptible for one person and easily detected by another. For a different chemical, it may be the reverse.

These thresholds can easily vary from one person to the next by a factor of a thousand.

Mac Leod also points out that the human genome contains nearly 350 olfactory genes — far more than for vision or hearing — resulting in highly individualised odour detection.”

When I send samples out to testers, I do see these differences in sensitivities to ingredients. I try to distinguish between people’s preferences and the way they smell a scent because both will determine whether a scent works for them, and differences in people’s skin will add yet another variable. Several questions become relevant. Does the tester like the smell of some ingredient like ambroxan or cosmone musk or jasmine sambac, etc? How strongly does the tester smell it, from being very sensitive to being average to being anosmic to it? And how does it do on the tester’s skin? Of course interactions between ingredients affect the outcome too, so I need to think about both the parts and the whole. It’s a fascinating topic to me.