Sniffing Dogs Have Expectations of What They're Looking For

Dogs have a mental representation of what's at the end of an odor trail.

Posted Mar 05, 2018

Dogs perceive odors as representing specific objects

Research continually shows that dogs have highly evolved cognitive and emotional lives. I just learned of a new study that has profound implications for what's happening in dogs' brains when they're tracking a scent. Here is a brief summary of a study by Juliane Bräuer and Julia Belger called "A ball is not a Kong: Odor representation and search behavior in domestic dogs (Canis familiaris) of different education." Their essay isn't yet available online, but it's worth calling attention to what these researchers discovered because it shows yet another example that dogs have future expectations. (For more discussion, see "Dogs Think About and Plan For the Future, Don't They?") A brief summary of this research project can be found in a piece called "Ball or stuffed toy—do dogs 'know' what they're smelling?" in which there are some details of how the researchers conducted their work. 

To learn what the dogs were expecting, the researchers studied 48 dogs, 25 of whom had previous training with police or a search and rescue team (working dogs) and 23 who had no previous training in the families with whom they lived. They used what's called a violation-of-expectation paradigm in which the dogs tracked the odor of one object (A), but at the end of the trail they found object B. In a pre-test, two objects which each dog liked to retrieve were identified and in 4 subsequent trials, a scent trial was drawn with 1 of the 2 toys. At the end of the trail, the dogs found either the toy with which the trail was drawn  (the "normal condition") or the other toy (the "surprise condition"). 

The researchers filmed the dogs as they followed the odor trail so they were able to analyze what the dogs did in each situation. They write, "In the first trial, dogs showed measurable signs of 'surprise' (i.e., further searching for Target A) when they found Target B, which did not correspond to the odor of Target A from the trail. We conclude that dogs represent what they smell and search flexibly, which is independent from their educational background." The working dogs were more efficient than the family dogs in the first round, but the family dogs caught up to them in subsequent trials. 

What's happening in the dogs' brains as they're sniffing?

I really want to know more about what's happening in dogs' brains while they're tracking different scents, and I imagine that non-invasive neuroimaging studies will shed further light on these sorts of questions. For more discussion on these types of studies, please see an interview with Emory University neuroscientist Gregory Berns in his essay, "What It's Like to Be a Dog." 

The study by Juliane Bräuer and Julia Belger shows that simple and non-invasive experiments can shed light on what dogs are thinking and what they expect in the future. Please stay tuned for more discussions of the fascinating cognitive and emotional lives of dogs and other animals. There's still a lot to learn, and how exciting it is to see what's being discovered in comparative research that doesn't harm the animals being studied. 


Bekoff, Marc. Canine Confidential: Why Dogs Do what They Do. Chicago: University of Chicago Press. 2018.

Breuer, Juliane et al, A ball is not a Kong: Odor representation and search behavior in domestic dogs (Canis familiaris) of different education. Journal of Comparative Psychology (2018).  DOI: 10.1037/com0000115

More Posts