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.

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  1. Fascinating topic indeed, dear Laurie !

    I hope you don’t mind, I’ve translated Hood’s article and parts of your other topics on this subject in french, to make it possible for my french friends to understand them.
    These questions are crucial to us perfumistas, when we come to test fragrances and exchange on our feelings, which can be so different.

    I just love what you said here(nov 2008):
    “The upshot of all this for me is to be aware of and tolerant of our differences. Remember when you sniff or review something that your experience is just as valid as anyone else’s, but that other people may differ greatly in how they experience the same scent and their scent truth is just as real to them as yours is to you.”

    Thank you for helping us understand, and for sharing your ideas so sincerely !

    1. Thanks, Anne, and thanks for doing the translation work! I hope the information is helpful to people. And you’ve chosen a quote that does sum up my sincere hope that this information and research will help us understand each other as well as the fragrances we’re sniffing!

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