Are Humans Really Worse at Smelling than Dogs?

The idea that humans have a worse sense of smell than other animals is a pervasive myth. Learn the reality in this episode of BrainStuff, based on this article: https://health.howstuffworks.com/human-body/systems/nose-throat/human-sense-smell-good-as-dog.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff, a production of I Heart Radio,
Hey brain Stuff, Lauren bog Obam Here. The long held
and much perpetuated belief that dogs have a sense of
smell superior to their trusty humans is total bunk, according
to a review published in the journal Science. The author

(00:22):
was Rutgers University sensory neuroscientist Dr John McGann, who sniffed
out the truth by reviewing years of prior olfactory related
research and comparing brain's responses to smelly stimuli in mice, dogs,
and humans. Before the article this episode is based on,
has to Work, spoke with McGann via email. He said,

(00:44):
when we started working with people, it was impressive how
excellent the human sense of smell really is. And I
started closely reading the many years of previous work on
the subject. So where did the idea of canines as
superior smeller has come from? McGann traced it back to
the works of one Paul Brokaw, a nineteenth century era

(01:06):
neuro anatomist. Brokaw dubbed humans as non smellers without any
sort of sensory testing to back that up. McGann wrote
in his review he believed that the evolutionary enlargement of
the human frontal lobe gave human beings free will at
the expense of the old factory system. Brokaw also noted
that other mammals feature old factory bulbs that are much

(01:29):
larger in proportion to the rest of their brains than
those in human beings. For example, of primates and humans
have an old factory bulb making up just zero point
zero one percent of the brain by volume, which compared
with two percent of the average mouse brain can seem
a little paltry, but this doesn't make humans any worse
at smelling. McGann explained, the human bulb is a very

(01:51):
small percentage of the human brain, which is part of
the origin of the myth that humans are bad smellers,
but it's actually quite large in absolute terms, much bigger
than a mouse, say. It's also richly interconnected with many
other brain regions that are larger and do more powerful
computations in humans. That's not to say that certain species

(02:12):
don't excel at identifying specific types of sense. However, in
the research, dogs were better at discerning between urins and
humans were better at differentiating between wines. Began wrote in
the review when an appropriate range of odors is tested.
Humans outperform laboratory rodents and dogs in detecting some odors

(02:33):
while being less sensitive to other odors. He notes that
humans are even capable of following scent trails in the
great outdoors. He said via email, it's difficult to make generalizations,
but I think it's fair to say that though the
human olfactory system is different than the rodent or dog
olfactory system, it's not worse than they are. And in

(02:55):
addition to being more powerful than you previously thought, the
human sense of smell is actually more important too. Smells
can cause us to recall specific associated memories and can
also elicit related behavioral and emotional responses. Personal odor can
also relate information about anxiety, stress levels, even reproductive status,

(03:15):
all things we once thought were only communicated by non
human animals. McGann said smell is underappreciated in our daily lives.
Most of the flavor of food is actually its smell
reaching the nose by going up through the back of
the throat. We're also beginning to understand that humans communicate
information about our genetics, diet, and emotional state through individualized

(03:37):
body odors that influence the behavior of other people, often subconsciously. Furthermore,
our sense of smell begins declining somewhere around the age
of sixty, and an improperly functioning olfactory system can be
a symptom of neurodegenerative diseases like Alzheimer's or Parkinson's. McGann
said loss of smell can thus be veried stressing for people,

(04:01):
which is one of the reasons I wrote this article
and to increase popular awareness of the importance of smelling
humans and hopefully encourage more emphasis on the development of
all factory medicine. Today's episode is based on the article
a human sense of smell is actually as good as
the dog's on house toff works dot com, written by

(04:23):
Leo Hoyt. Brain Stuff is production of I Heart Radio
in partnership with how stuff works dot Com, and it's
produced by Tyler Klang. Before more podcasts from my heart Radio,
visit the I heart Radio app, Apple Podcasts, or wherever
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