What’s the best smell in the world? Researchers set out to find out. Here’s what they learned.
You’ve probably heard it said that, while there are, inarguably, pleasant and unpleasant odors, much of what people like and dislike aroma-wise is determined by culture and life experience.
We were told exactly this in a 2017 interview with Dawn Goldworm, a nose and the founder of olfactive branding company, 12.29, who said that, while some ingredients, like lavender and rose, can have calming effects, because they’re used in a variety of different ways around the world, they might not evoke these feelings in some populations.
In Central and South America, for example, Goldworm said, “lavender is used in baby products. “So, if you have young children, and you’re looking to have a relaxing day at the spa, and everything is scented with lavender, you’re going to be thinking about your kids the whole time. Not that you would ever not think about your children, but maybe you wanted an hour or two to yourself.”
Now, authors of a new collaborative study between researchers at Karolinska Institutet, Sweden, and the University of Oxford, UK, say they have found otherwise. The scientists conducted a study, the results of which, they argue, show that the smells we like or dislike are not influenced by culture but by the structure of the particular odor molecule.
“We wanted to examine if people around the world have the same smell perception and like the same types of odor, or whether this is something that is culturally learned,” said Artin Arshamian, researcher at the Department of Clinical Neuroscience, Karolinska Institutet, in a research brief. “Traditionally it has been seen as cultural, but we can show that culture has very little to do with it.”
The researchers found that certain smells were liked more than others regardless of the cultural affiliation of participants.
“Cultures around the world rank different odors in a similar way no matter where they come from, but odor preferences have a personal – although not cultural – component,” said Dr Arshamian.
“Indigenous populations in disparate environments”
The study involved a total of 235 individuals from nine communities representing different lifestyles: four hunter-gatherer groups and five groups with different forms of farming and fishing. Some of these groups have very little contact with Western foodstuffs or household articles.
“Since these groups live in such disparate odiferous environments, like rainforest, coast, mountain and city, we capture many different types of ‘odor experiences’,” said Dr Arshamian.
Participants were asked to rank 10 smells on a scale of pleasant to unpleasant. The results show variation between individuals – which the researchers attribute to molecular structure (41%) and personal preference (54%) – but global correspondence on which odors are pleasant and unpleasant.
“Personal preference can be due to learning but could also be a result of our genetic makeup,” said Dr Arshamian.
The scents included:
- Vanillin – Vanilla, extracted from vanilla beans. Sweet, warm scent. Used as flavoring in baking and food. Popular fragrance ingredient.
- Ethyl Butyrate – Fruity scent, like peaches or pineapple. Used in fragrance and in artificial flavoring in alcoholic beverages.
- Linalool – Flowery, spicy scent, similar to lavender and bergamot. Commonly used in fragrance.
- Eugenol – Spicy scent and the main element of clove essential oil. Used as a flavoring for foods and teas, and as a fragrance ingredient.
- 2-Phenylethanol – Floral scent that smells like roses and also like carnation, orange blossom, and geranium. Common fragrance ingredient.
- 1-Octen-3-ol – Also known as “mushroom alcohol,” has an earthy mushroom-like scent, also described as “raw chicken.” Used in fragrance and in pesticide to attract biting insects.
- Octanoic acid – Cheese-like odor also described as smelling like goat. Medium-chain fatty acid naturally found in palm oil, coconut oil, and human and animal milk. Used as a disinfectant and food additive.
- 3-Isobutyl-2-methoxypryazine – Fresh bell pepper scent. Also present in the smell of coffee and spinach. Used in fragrance, detergents, candles, deodorants, gums, and candies
- Dimethyl disulphide – Garlic-like scent. Natural compound emitted from bacteria, fungi, plant,s and animals. Used as flavoring in food.
- Isovaleric acid – Pungent, cheesy, or “sweaty feet” scent. Found in feces and blood. Its volatile esters have pleasant odors and are widely used in perfumery.
And the winner is….
Vanilla was considered the most pleasant scent across cultures, followed by peachy/pineapple-y ethyl butyrate. The smell ranked the least pleasant was isovaleric acid, which is found in cheese, soy milk, apple juice, and foot sweat.
Dr Arshamian, muses that a possible reason why people consider some smells more pleasant than others regardless of culture is that such odors increased the chances of survival during human evolution.
“Now we know that there’s universal odor perception that is driven by molecular structure and that explains why we like or dislike a certain smell,” Dr Arshamian said. “The next step is to study why this is so by linking this knowledge to what happens in the brain when we smell a particular odor.”
Wintergreen and maple in France and Canada
These findings are interesting but not shocking. When one looks up the smells used in the study, the odors on the second half of the list are mostly described as “unpleasant.” It’s not a surprise that feces and sweat rank low in popularity no matter where you’re from. And, the suggested explanation seems obvious: we are put off by smells that can make us sick (feces and bacteria) and drawn towards smells that smell clean and/or good to eat because moving away from one and toward the other will help us live longer. Without the research, however, that’s just a hypothesis, so it is valuable. Still…do the findings really “show that culture has very little to do” with how we perceive scent? Different studies suggest otherwise.
In a 2016 study, for instance, researchers at the Montreal Neurological Institute found that two people from different cultures smelling the same thing can have remarkably different reactions, even when those cultures share the same language and many traditions.
In a partnership with researchers from the Lyon Neuroscience Research Centre in France, clinical neuropsychologist Jelena Djordjevic tested subjects in Quebec, Canada, for their subjective impressions of different scents, while their collaborators in France did the same with French subjects. This study used smells that are largely considered pleasant, or at least not overtly “unpleasant.” These were: anise, lavender, maple, wintergreen, rose, and strawberry.
Participants were asked to smell each scent first without knowing what it was then again after being told its name. They were then asked to rate the scent on pleasantness, intensity, familiarity, and edibility. The scientists also measured the subjects’ non-verbal reactions to each scent, including sniffing, activity of facial muscles, respiration, and heart rate.
They found significant differences between ratings of the same smells among the French and French-Canadian subjects. The French gave wintergreen much lower pleasantness ratings than French-Canadians. A press release explained that, in France, wintergreen is used more in medicinal products than in Canada, where it is found more in candy. The French were more familiar with the scent of lavender while Canadians were more familiar with maple and wintergreen. Anise was rated similarly in two cultures but was described more often as “licorice” in Quebec and as “anise” in France.
Telling the subjects what they were sniffing increased their familiarity, pleasantness, and edibility ratings, and cultural differences disappeared or decreased when the names were provided, including for non-verbal reactions.
The brief states “This study reinforces the idea that our brain’s processing of odor is not simply its reaction to the chemical compounds that make up the scent. It is influenced both by our previous experience with the scent and our knowledge of what the scent is.”
The stink bomb experiment
Another experiment that lends credence to the “scent perception is tied to culture” argument is Pamela Dalton’s quest to find the perfect stink bomb. Dalton, a cognitive psychologist at the Monell Chemical Senses Center, is known as the woman who created the world’s worst smell. In 1998, she was tasked with developing a stink bomb for the Department of Defense and her experiments found that people from different backgrounds and different parts of the world, who grew up smelling and eating different things, often completely disagreed about which smells were good or bad.
Eventually she did find a formula that was dubbed “Stench Soup,” but not without trial and error.
Do any smells evoke more healing and stress reducing effects in different areas of the world?
It will be interesting for the spa and wellness world when more people take up the task of conducting further research on cultural perceptions to pleasant smells and if any evoke more healing and stress reducing effects in different areas of the world.
Until then, don’t put any stinky feet aromatherapy treatments on your menus.
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