WEBVTT - Are Humans Really Worse at Smelling than Dogs?

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<v Speaker 1>Welcome to brain Stuff, a production of I Heart Radio,

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<v Speaker 1>Hey brain Stuff, Lauren bog Obam Here. The long held

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<v Speaker 1>and much perpetuated belief that dogs have a sense of

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<v Speaker 1>smell superior to their trusty humans is total bunk, according

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<v Speaker 1>to a review published in the journal Science. The author

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<v Speaker 1>was Rutgers University sensory neuroscientist Dr John McGann, who sniffed

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<v Speaker 1>out the truth by reviewing years of prior olfactory related

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<v Speaker 1>research and comparing brain's responses to smelly stimuli in mice, dogs,

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<v Speaker 1>and humans. Before the article this episode is based on,

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<v Speaker 1>has to Work, spoke with McGann via email. He said,

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<v Speaker 1>when we started working with people, it was impressive how

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<v Speaker 1>excellent the human sense of smell really is. And I

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<v Speaker 1>started closely reading the many years of previous work on

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<v Speaker 1>the subject. So where did the idea of canines as

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<v Speaker 1>superior smeller has come from? McGann traced it back to

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<v Speaker 1>the works of one Paul Brokaw, a nineteenth century era

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<v Speaker 1>neuro anatomist. Brokaw dubbed humans as non smellers without any

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<v Speaker 1>sort of sensory testing to back that up. McGann wrote

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<v Speaker 1>in his review he believed that the evolutionary enlargement of

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<v Speaker 1>the human frontal lobe gave human beings free will at

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<v Speaker 1>the expense of the old factory system. Brokaw also noted

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<v Speaker 1>that other mammals feature old factory bulbs that are much

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<v Speaker 1>larger in proportion to the rest of their brains than

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<v Speaker 1>those in human beings. For example, of primates and humans

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<v Speaker 1>have an old factory bulb making up just zero point

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<v Speaker 1>zero one percent of the brain by volume, which compared

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<v Speaker 1>with two percent of the average mouse brain can seem

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<v Speaker 1>a little paltry, but this doesn't make humans any worse

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<v Speaker 1>at smelling. McGann explained, the human bulb is a very

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<v Speaker 1>small percentage of the human brain, which is part of

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<v Speaker 1>the origin of the myth that humans are bad smellers,

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<v Speaker 1>but it's actually quite large in absolute terms, much bigger

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<v Speaker 1>than a mouse, say. It's also richly interconnected with many

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<v Speaker 1>other brain regions that are larger and do more powerful

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<v Speaker 1>computations in humans. That's not to say that certain species

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<v Speaker 1>don't excel at identifying specific types of sense. However, in

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<v Speaker 1>the research, dogs were better at discerning between urins and

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<v Speaker 1>humans were better at differentiating between wines. Began wrote in

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<v Speaker 1>the review when an appropriate range of odors is tested.

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<v Speaker 1>Humans outperform laboratory rodents and dogs in detecting some odors

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<v Speaker 1>while being less sensitive to other odors. He notes that

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<v Speaker 1>humans are even capable of following scent trails in the

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<v Speaker 1>great outdoors. He said via email, it's difficult to make generalizations,

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<v Speaker 1>but I think it's fair to say that though the

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<v Speaker 1>human olfactory system is different than the rodent or dog

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<v Speaker 1>olfactory system, it's not worse than they are. And in

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<v Speaker 1>addition to being more powerful than you previously thought, the

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<v Speaker 1>human sense of smell is actually more important too. Smells

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<v Speaker 1>can cause us to recall specific associated memories and can

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<v Speaker 1>also elicit related behavioral and emotional responses. Personal odor can

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<v Speaker 1>also relate information about anxiety, stress levels, even reproductive status,

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<v Speaker 1>all things we once thought were only communicated by non

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<v Speaker 1>human animals. McGann said smell is underappreciated in our daily lives.

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<v Speaker 1>Most of the flavor of food is actually its smell

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<v Speaker 1>reaching the nose by going up through the back of

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<v Speaker 1>the throat. We're also beginning to understand that humans communicate

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<v Speaker 1>information about our genetics, diet, and emotional state through individualized

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<v Speaker 1>body odors that influence the behavior of other people, often subconsciously. Furthermore,

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<v Speaker 1>our sense of smell begins declining somewhere around the age

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<v Speaker 1>of sixty, and an improperly functioning olfactory system can be

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<v Speaker 1>a symptom of neurodegenerative diseases like Alzheimer's or Parkinson's. McGann

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<v Speaker 1>said loss of smell can thus be veried stressing for people,

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<v Speaker 1>which is one of the reasons I wrote this article

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<v Speaker 1>and to increase popular awareness of the importance of smelling

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<v Speaker 1>humans and hopefully encourage more emphasis on the development of

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<v Speaker 1>all factory medicine. Today's episode is based on the article

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<v Speaker 1>a human sense of smell is actually as good as

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<v Speaker 1>the dog's on house toff works dot com, written by

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<v Speaker 1>Leo Hoyt. Brain Stuff is production of I Heart Radio

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<v Speaker 1>in partnership with how stuff works dot Com, and it's

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<v Speaker 1>produced by Tyler Klang. Before more podcasts from my heart Radio,

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