Although in everyday life it seems that we rely mostly on sight, hearing and touch to perceive the world around us, one sense is often underestimated. What is the strongest human sense?
They are taught from an early age that animals have a much superior sense of smell to us. But one researcher claims the idea of an inferior sense of smell comes from a 19th-century myth. Here’s how scientific knowledge about man’s strongest sense has evolved.
When neuroscientist John McGann, of Rutgers University in the US, began to compare the sense of smell in rodents with what was known about the human sense of smell, he had an epiphany.
What is the strongest human sense?
“We actually have an excellent sense of smell. There are quite a few experiments that show that the human sense of smell is quite similar to what you can see in a rat, a mouse or a dog,” he says.
He published an article about his findings in magazine Science.
McGann wondered why our noses got such a bad rap. He traced the idea back to the mid-1800s to the work of a researcher named Paul Broca.
What does smell have to do with free will?
“He was interested in free will and had the idea that smell was an animal sense and that it ‘forced’ animals to have sex and feed. And humans, given free will, could choose how they responded to odors and probably had a less strong or less specialized sense of smell than other animals,” says McGann.
Sigmund Freud took up this idea, arguing that smell invokes instinctive sexual behavior in animals. In humans, however, Freud believed that “the supposed loss of smell caused sexual repression and caused mental disturbances, especially if one ‘found pleasure in smell,'” McGann writes in his paper.
As scientists in the 20th century began to explore the sense of smell, they interpreted their findings in a way that reinforced the idea that smell was diminished in humans as they rose in feet and their noses were removed from the ground.
How does man’s strongest sense compare to that of other beings?
One example is that humans have about 400 different smell receptors in their noses, compared to more than 1,000 receptors in rats. “But actually, 400 is an extraordinary amount, and frankly, there are very few odors that are volatile enough to get into the air that people can’t smell,” McGann argues.
In theory, we can distinguish tens of millions of unique odors, or perhaps even more, according to NPR.
There have been some laboratory comparisons between the noses of humans and other mammals, but there is no consistent winner.
“People are better at some, dogs are better at others, and mice are better at different ones. It just depends on what chemical it is,” says McGann.
Case closed? Not nearly.
We have a better sense of smell than we think
“If the question is, ‘We have a better sense of smell than we think,’ I agree. We have a more developed sense of smell than we think,” says Alexandra Horowitz, professor of psychology at Barnard College, USA.
But, Horowitz says, when the question is whether we’re as good as dogs at using our sense of smell, she disagrees. She even wrote a book on the subject, called “Inside Of A Dog”. She says there is no comparison between the performance of a scent-tracking dog and a human.
“It’s one thing to talk about the ability” to smell, she says. Clearly, we have the ability to distinguish between a large number of odors. But, she says, “Are we doing anything behaviorally similar to these olfactory animals? No, we generally don’t.”
The sense of taste
Horowitz says the one place humans excel is when the strongest human sense is used to enjoy food. Subtle and pleasant aromas come to our nose from the back of the mouth.
“Without smell you can’t taste and that’s a real loss. I’ll admit this is something we’re great at, maybe even better than dogs,” she says.