The cultural narrative has been established for decades: dogs are the ultimate sniffers. People? We are basically blindfolded. We are “nonsmellers”, olfactory underdogs in a world dominated by dog noses. This hierarchy feels intuitive. It feels real. But according to a detailed review published in Science, it’s also complete nonsense.
The myth persists because it is easy to accept. It reinforces the idea that we have evolved from our animal instincts in favor of a higher cognition. But Dr. John McGann, a sensory neuroscientist at Rutgers University, says we need to stop believing the hype. His team just didn’t guess. They spent years reviewing olfactory studies from decades earlier. They looked at the data. They compared brain responses to odor stimuli in mice, dogs and humans. And what they found challenges the foundation of how we think about our own biology.
The Broca error
Where does this inferiority complex come from? McGann attributes it to the 19th century and neuroanatomist Paul Broca. Broca famously referred to people as “nonsmellers”. He did this without rigorous sensory testing to back it up. His theory was evolutionary and philosophical. He believed that by increasing the size of the human frontal lobe to give us free will and complex thought, we sacrificed our olfactory system in the process. For him it was a zero sum game.
Broca also noted the anatomy. Especially the olfactory bulb – the structure of the brain responsible for processing smells. In mice and other mammals, this bulb is huge relative to the size of the brain. In humans, it makes up only 0.01 percent of the brain’s volume. For an average mouse, it’s about 2 percent. On paper, the human sense of smell seems weak. Looks poor.
But volume relative to total brain size is a misleading measure. McGann points out that while the human bulb is only a small percentage of the whole, it is absolutely huge. It is much bigger than a mouse. More importantly, it is closely related to other brain regions that are larger in humans and perform more efficient calculations. We haven’t lost our sense of smell. We integrate it into a more complex system.
Not worse, just different
It doesn’t mean that dogs smell bad. They are exceptionally good at certain tasks. Dogs excel at separating complex mixtures such as urine, which is crucial for their social and territorial behavior. People? We are better able to distinguish more nuanced and critical scents. We can choose great wines. We can detect volatile chemicals that signal danger. We can even follow scent trails in the wild, although not as fast as a bloodhound.
“When the appropriate odor spectrum is tested, humans outperform laboratory rodents and dogs in detecting some odors, but are less sensitive to other odors.”
The key word here is range. If you test a limited number of chemicals, the species can win. Test a wider, more ecologically relevant set, and the human nose can often hold its own. It is difficult to make broad generalizations. The human olfactory system is different from the olfactory system of a rodent or a dog. But it’s not worse. It is adapted to a different world.
Hidden olfactory tongue
We also underestimate the true benefit of smells. It’s not just about spotting rot or food. Scents evoke special memories. They evoke behavioral and emotional responses that override conscious thought. Your personal scent conveys things you don’t want to share with others. It reveals anxiety. It tells about the level of stress. It even conveys reproductive status. We thought these were exclusively animal characteristics. People do them too, often unconsciously.
This communication is vital. Loss of smell is not only a nuisance. It’s a symptom. A faulty olfactory system can be an early sign of neurodegenerative diseases such as Alzheimer’s or Parkinson’s. It’s a glimpse into brain health that we’re just beginning to understand.
“Most of the taste of food comes from its smell, which travels from the throat to the nose.”
We take this for granted. We think of taste as a function of tongue. But taste is largely smell. When this sense fades, the world becomes boring. It becomes less alive.
Why this is important now
McGann wrote his review to change the conversation. To raise awareness. We recommend putting more emphasis on “olfactory medicine”. We know that the sense of smell begins to weaken around the age of 60. Hormonal changes, head injuries and dental problems can affect this earlier. These factors are controllable but require attention. We ignore our noses until they fail us.
Belief in the superiority of dogs has never been supported by data. It was supported by 19th century speculation and a misunderstanding of brain anatomy. The human nose is underrated. It’s powerful. It is related to our emotions, memories and health. It’s time to stop treating it as a relic.
We are not odorless. We just know better when not to listen to the noise.
