We’ve all heard that humans have an inferior sense of smell relative to dogs, mice, and anything furry with a nose. But that’s nothing more than a 19th-century myth, according to a literature review published in Science. The review explores the religious politics, philosophical speculation, and straight-up bad science that stoked the belief that the human sense of smell was inferior to that of other animals, concluding that human olfaction is nothing to sniff at.
John McGann, a neuroscientist at Rutgers University and coauthor on the study, told Fatherly that the notion that humans have a puny olfactory organ and diminished ability to smell is nothing but a “myth”. Rather, McGann claims that the sorry reputation of our olfaction began 150 years ago, with an attempt to separate humans from sex-crazed beasts. “There was this idea in the 19th Century that becoming part of a civilized, rational creature with free will required you to lose your ability to be compelled into dirty sexual behavior by smell,” he says.
The story of our slandered sniffers begins with Paul Broca, the celebrated 19th Century neuroscientist who discovered the brain’s speech center in the eponymous “Broca’s area”. Broca divided mammals into two broad categories—those driven by smell and those superior breeds immune to olfactory temptation (primates, humans). This dichotomy set the stage for future scientists to spurn the human olfactory system. Even Freud got in on the action, declaring that all men who take pleasure in fine scents were, you guessed it, sexual deviants.
“It goes back to the Enlightenment,” Ann-Sophie Barwich, a self-proclaimed “smellosopher” who studies olfaction along with the history and philosophy of science at Columbia University and was not involved in the study, told Fatherly. “Cognition was attributed to vision. It was all light and reason. Smell was for the perverts, lunatics, idiots, and women. It’s complete bullshit.”
Nonetheless, it has proven difficult to uproot a myth so deeply entrenched in our culture. “For various reasons, it’s been difficult to prove that our sense of smell has been unfairly degraded and get the scientific culture and popular culture at large to listen,” McGann says.
So McGann took his review one step further and examined the human brain structures responsible for olfaction, once believed to be relatively weak. But using new technology, McGann found that the number of neurons in the brain structure called the olfactory bulb remains consistent across species. Human olfactory bulbs are right up there with those belonging mammals named for their noses, such as large-snouted capybaras and proboscis monkeys.
But seeing is believing. “When you work with a human brain, you see the [olfactory] bulb as this tiny little thing on the bottom,” McGann says. “We took the olfactory bulb from a human brain. And we took the olfactory bulb from a mouse brain. And we put them next to each other and I think everyone in the room gasped.” McGann explained that the human olfactory bulb looked huge next to the olfactory bulb of the mouse, a species known for its superior sense of smell.
Barwich says the study seems robust, and that she agrees with most of its conclusions. She adds that the myths surrounding human olfaction have gradually been debunked over time. For instance, Barwich says the notion that smell is an animalistic, base sense doesn’t jibe with the very cognitive way that humans appreciate sniffing the elaborate qualities of perfume or wine.
“To appreciate smell means to really pay attention,” she says.
She adds that says that to discount smell means to discount its significant role in the experience of the flavor of food, which was improved by spices (the trading of which built civilization). Barwich suggests that, for humans, smell creates the “material texture of reality.”
McGann cautions that, while the significance of smell in humans has been woefully misunderstood, his research has not demonstrated that humans have a superior sense of smell. Instead, he concludes that we are likely just as good at using smell for our specific needs as any other mammal. “It depends on the odor you’re asking the animal to detect,” McGann says. “It depends on whether the chemical is in the air, which humans are built to detect, or if the chemical is still sitting in liquid on the side of a fire hydrant, which a dog can detect.”
For McGann, the findings mean it’s time to put a premium on smell—especially in early childhood education. “Go out and put your nose on the ground in the park and see what you smell. Stop and think about the scotch, or the steak, or the vegetable medley,” he says. “I’ve never heard anyone say ‘Teach your baby about smell.’ I’ve never seen anyone say, ‘Here’s an activity map for your infant with the stuff to touch, and stuff to listen to, and stuff to smell.’”