What do we talk about when we talk about smell? Mostly other things. English speakers frequently describe a scent according to what it reminds us of, not using a specific name for the odor itself.
Linguists Nicole Kruspe, at Lund University in Sweden, and Asifa Majid, at the Netherlands' Max Planck Institute for Psycholinguistics, say that, for millennia, Western scholars dismissed scents as unknowable, or at least unnameable.
They cite philosophers Plato: "The varieties of smell have no name . . . but they are distinguished only as painful and pleasant," and Immanuel Kant: "Smell does not allow itself to be described, but only compared through similarity with another sense."
Neuroscientists have proposed that the barrier to naming the odors is within us, wired into our brains.
But because a thing might hold true for Westerners or English speakers does not mean it is universal to the human experience. Kruspe and Majid are studying hunter-gatherer cultures in Asia, where people take a very different approach to odors.
In 2014, Majid discovered that people who speak the Jahai language named odors as easily as English speakers identify colors.
In English, "most people describe odors in terms of their sources," said psychologist John McGann, who studies the olfactory system at Rutgers University in New Jersey.
In contrast, the common English names of colors such as purple, gray or yellow are abstract. (This is not a hard-and-fast rule, McGann noted, citing colors like gold, olive and coral.)
Majid's previous study, however, was unable to suggest why Jahai speakers had the ability to identify odors by abstract names. "English and Jahai speakers differ from one another in all sorts of ways," Kruspe and Majid wrote in an email to The Post.
Among other things, the hunter-gatherer Jahai, who live in mountain rain forests on the border of Malaysia and Thailand, do not have a written language.
In a new study, published in Current Biology on Thursday, Kruspe and Majid compare the smelling skills of two other groups in the Malay Peninsula: Semaq Beri speakers, who like the Jahai are hunter-gatherers, and Semelai speakers, who are horticulturalists.
The linguists recruited 20 Semaq Beri and 21 Semelai people to participate in an experiment. In one part of the test, researchers asked subjects to name the colours of colour chips.
In another, subjects had to identify the odors in 16 different "Sniffin' Sticks" - akin to markers but filled with smelly chemicals instead of ink. (The odorants: apple, anise, banana, cinnamon, clove, coffee, fish, garlic, leather, lemon, licorice, orange, peppermint, pineapple, rose and turpentine.)
The Semaq Beri hunter-gatherers used abstract words for color and odor at equal rates. But the horticulturalist Semelai, like English speakers, used abstract words for color and mostly source-based words for odor.
What's more, Semelai speakers were more varied when describing the odors. If you and I lack a common vocabulary for odors, you might say an anise-scented "Sniffin' Stick" smells like licorice and I might say it smells like cough medicine.
Semaq Beri "smell naming is statistically better than the Semelai smell naming," the study authors said.
McGann, who was not involved with this research, called this ability "an intriguing result."
He also said that he would like to see what biological mechanisms are at play - if Semaq Beri speakers have differences in odor receptors, or the way their brains process odors, or possibly something else.
"It would also be fascinating to figure out what exactly it is about hunter-gatherer culture that underlies this difference," he added, "since mere environment is clearly not sufficient."
While foraging in a dense rain forest, communicating scent signals might be critical to survival.
"The smell of tiger urine would be something to note," Kruspe and Majid pointed out.
But there are richer differences between the hunter-gatherers and the horticulturalists, too, beyond the way these groups acquire food.
To avoid mingling odors, Semaq Beri speakers cook certain types of meats over different fires. Some smells, according to Semaq Beri culture, have healing properties. Others cause sickness. And an individual's personal odor is special.
"The hunter-gatherer Semaq Beri do not think a brother and sister should sit too close together because their smells will mix," the authors said, "and this is considered a sort of incest."
Kruspe and Majid's research does not rule out factors like environment and biology. But they argue that cultural experiences contribute disproportionately to this ability.
"We believe that cultural practices and beliefs help to hone these skills," they said. This does not mean that most humans are poor smellers - in fact, McGann argued in a review of the scientific literature in May, the human sense of smell is more sophisticated than its reputation.
But Kruspe and Majid propose that, when people settle into, say, horticulture or postindustrial society, other senses become relatively more important than smell. You don't, I hope, need to sniff for tiger urine on the way to Starbucks.
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