There is not really much research being done with regard to the human sense of smell so the widely known belief that animals have superior sniffing abilities persist.
A new research published in the journal Science, however, falsifies 150 years of myth as it reveals that the human olfactory sense can work just as well as our canine companions'.
Rutgers University neuroscientist John McGann traced the origins of the wrong belief about humans' nonessential sense of smell back to anatomist and anthropologist Paul Broca, who relied on observing the size of the olfactory bulb in different mammals to make the claim. McGann published his findings, providing scientific research as evidence, to bust the myth.
According to McGann, the belief that humans have a weaker sense of smell began in the 19th century when Broca compared the size of the olfactory bulb in the brains of different mammals. According to Broca's observation, the human sense of smell is not as sharp as that of animals because our olfactory bulb takes up a really small portion of our brain.
"Broca believed that a key part of having free will was not being forced to do things by odors. And he thought of smell as this almost dirty, animalistic thing that compelled behaviors ... So he put humans in the nonsmeller category - not because they couldn't smell, but because we had free will and could decide how to respond to smells," McGann explains.
Unfortunately the mistaken belief was picked up by none other than Sigmund Freud, a major contributor in the field of psychology. Freud supported Broca's idea and claimed that a strong sense of smell is akin to animalistic behavior and that it is something humans grow out of as they become rational adults.
McGann also clarifies that the human olfactory bulb did not shrink as humans evolved, but that it remained the same size even as the brain grew larger and processed more complicated information.
According to McGann, several research and experiments show that humans can track odors just as well as dogs.
Past scientific research supporting Broca's claim revealed that rats and mice have about 1,000 different kinds of smell receptors, which is more than twice that of the 400 smell receptors found in humans. McGann, however, says that the human brain makes up for the difference in the number of receptors.
"The truth is that 400 different receptors still offer a tremendous range. There are very few odors that humans can't smell despite having practically fewer receptors than rats, mice, and dogs," notes McGann.
He adds that different species just have different sensitivities to smells and, while other animals usually win in sniffing tests against humans, humans also outperform other mammals in other experiments.
"Humans are best at some, and dogs are best at some, and mice are best at some," McGann says.
McGann also brought up a University of California Berkley experiment that proves that humans - in this case, blindfolded and earmuffed undergraduate students - are perfectly capable of tracking a scent even in an open field. You can watch the experiment below.
A Smelly Conclusion
McGann's conclusion, of course, only reinforces the fact that humans also possess a keen sense of smell. In fact, Tech Times reported about a woman who accurately sniffed out and identified Parkinson's disease in 2015.
Experts, however, seem to be on different sides, even if they agree that the olfactory sense plays a huge role in humans.
"If the argument is, 'We are better smellers than we think,' I assent ... [But] do we behaviorally do anything that's anywhere similar to these olfactory animals? No, we generally don't," Barnard College psychology professor Alexandra Horowitz says.
Horowitz adds that the capacity to smell and identify odors does not necessarily mean humans are better than other mammals.