Dogs Really Do Smell You More Than They See or Hear You

New research shows just how important scent is for dogs.

Posted Sep 23, 2020

If you read this blog on a regular basis you know that it is primarily designed to address what psychology research shows about behaviors across species.  My view is that the field of “comparative psychology” specializes in addressing what all species have in common about how they behave and what impacts their behaviors.  One of the reasons I think this is so important is because the more we understand about the basic roots of behaviors the better equipped we are to deal with those behaviors or even try to change them.  Even though I primarily look at behaviors across species I do focus the blog largely on human behaviors. (I am a clinical psychologist and human behavior is my primary interest.)

But every so often I find an article about behaviors specifically related to one species that I think it is useful to share.  This month I found an article in the International Journal of Comparative Psychology specifically about dogs and how they recognize their owners — “Discrimination of person odor by owned domestic dogs” by Alexandra Horowitz

If you own, or have ever owned, a dog, it might surprise you to know that the question of whether dogs recognize their owner primarily through smell has gone unanswered for years.  I know when I was younger I often heard that this was how dogs recognized familiar people.  But I also heard it was through sight, even though dogs have different visual systems than humans and other animals, or through voice or other sounds.  But what the present article supports is that it is indeed smell that is the clearest way that dogs recognize their owners and other familiar people.

Smell (or “olfaction” in the animal research world) plays a major role in how dogs recognize others.  They recognize other dogs, and determine which are familiar and safe, through smell.  Dogs also recognize members of other species through smell.  This is another way that they can identify who is safe and who might be a danger.  They even recognize dog toys and other objects through smell.

In the article the author makes a clear statement that, for dogs, “odor is recognized to be their primary source of information."  Other senses play a major role but this research, and research like it, show that dogs rely mostly on smell.  And not only for recognizing others but also for things like recognizing what direction someone is moving or how far someone is behind them. 

What was particularly interesting about this study was that it addressed how dogs reacted and used the smell of a familiar person even if that person was not actually there.  This was an important step because other research has often been limited to testing the scent of a person who was actually physically around the dog.  In that way, it was hard to say what led to the dog recognizing the person, since it would not have been clear if the dog might have recognized them in some other way.  If, for example, the person was actually there, it would not be certain whether the dog actually smelled the person most or might have heard some small noise the person made.  Or the dog may have recognized some small shadow given off by the person.  This is particularly important because dogs, as many owners already know, have visual and hearing abilities more sensitive than those of humans.

What this author did was study how dogs reacted to the smell of familiar people even when those people were not in the room.  Owners brought the dogs in and then each owner was given a new t-shirt to wear overnight.  These t-shirts were then stored separately in clean containers and not opened until the experiment started.  Dogs were then encouraged to seek out something familiar to them through a series of verbal prompts that included tapping and calling out (one interesting note here is that the experiment actually used the term “dog talk” for the specific means they used to get the dogs’ attention).  All of this led to the dogs going to the box with the owners’ smells more often than those with the shirts of unfamiliar people.

I also liked that this study made sure to check if people who wanted to be involved with the study were not dog owners who actively discouraged their dogs from relying on smell.  When it comes to domesticated dogs, this is an important issue because dogs naturally rely a great deal on smell but can be trained to not do so.  Owners will sometimes take this step to stop dogs from doing things like sniffing people or objects that can be embarrassing.  This study would have been difficult to interpret if the researcher had not made sure that the canine participants had not been trained not to rely on smell.

I am being very basic in my explanation of this study.  There were a number of steps involved and the study was rather complex.  I also appreciated that the author was very specific about why some dogs were dropped from the study and also about some mistakes that were made with data collection.  But in the end, this is a clear study showing not only that smell is important for dogs but also primary in how they function.

People who have dogs in their homes would be wise to recognize just how essential smell is for their companions.  Taking care of dogs means helping to care for their sense of smell in addition to the other things they need.  So owners should think twice about how much they train dogs from not relying on smell.  I know that some things dogs do when they smell people or objects can be embarrassing or problematic (like dogs getting in between you and another person so they can smell the person).  But it is important for dogs to rely on smell and interfering with that can be problematic for them.

Research like this is useful for understanding how dogs function differently from humans.  We can get so close to dogs that we may not always appreciate they live their lives differently than we do.  Recognizing differences in how dogs and humans function can go a long way in helping them both live happy and healthy lives together.

References

Horowitz, A. (2020). Discrimination of person odor by owned domestic dogs. International Journal of Comparative Psychology, 33.