That might seem a paltry number considering how many things there are out there in the world to smell. Jason Castro of Bates College and Chakra Chennubhotla of the University of Pittsburgh used computerized techniques to analyze 144 smells and came up with ten basic scents, some (popcorn?) rather unexpected.
Says Castro to the BBC, ”You have these 10 basic categories because they reflect important attributes about the world — danger, food and so on. If you know these basic categories, then you can start to think about building smells.”
Any natural scent is a blend of the ten basic categories, Castro explains.
He and Chennubhotla say their findings could be useful in developing new sorts of perfumes or to otherwise manufacture scents.
If it is the case that we only sense a total of ten smells, we should feel quite a bit humbled vis-a-vis other animals. Dogs’ sense of smell is 10,000 to 100,000 times more acute than ours, the result of their having up to 300 million olfactory receptors in their noses; we have a mere six million. “If you make the analogy to vision, what you and I can see at a third of a mile, a dog could see more than 3,000 miles away and still see as well,” James Walker, former director of the Sensory Research Institute at Florida State University, explains.
Dogs’ noses also have a different anatomical structure from ours that makes it possible for them to detect a teaspoon of sugar in the equivalent of two Olympic-size pools (that’s 2 million gallons) and to sniff out bombs. While we smell and breathe through the sane airways when we inhale, dogs have a fold of tissue inside their noses that keeps those two functions separate.
Here’s a full list of what we humans can smell.
Think flowers first of all and other pleasant scents.
Nothing like the, well, woodsy smell of a forest or of pine trees.
3. Fruity (non-citrus)
Apparently we humans can pick up fruity smells but not vegetable-like ones. Is there anyone who prefers the smell of a zucchini to an apple?
This smell is, it goes without saying, very likely not something you’d want made into a perfume.
It’s a smell many of us associate with words like “clean” and “refreshing” for good reason.
No wonder manufacturers put sugar into just about every food: it’s a smell we know too well.
Popcorn has been called a superfood. Perhaps its being one of the basic smells we detect is a reason for its appeal.
“Lemon” is, it seems, to be distinguished from a “fruity” smell. You might say that it is “fruity with a sharp (but not too sharp) twist.”
This would be anything with an overly intensely heady aroma like this Chinese fermented bean curd.
This last of Castro’s and Chennubhotla’s ten basic smells is one that we quickly learn to avoid and for good reason!
Photos from Thinkstock