We’ve shared a bit on this site about science’s take on animal intelligence. From which animals are potentially as intelligent as humans (dolphins) to how smart (or not smart) dogs may be, researchers have devised several scales for measuring cognizance and awareness as well as determining just what intelligence is.
Recently, something called Mirror-self recognition (MSR) has been touted as the benchmark for measuring intelligence. The idea is to place a mirror in front of an animal and observe how long it takes that animal or species to begin recognizing itself. Scientists believe that this basic level of self-awareness is a precursor to greater intelligence. They’ve used it to study young children, great apes, dolphins, elephants, and even magpies, and recently they determined that because dolphins are able to start recognizing themselves at an earlier developmental stage in life, they must, therefore, have a greater capacity for developing intelligence. The ability to be self-aware, they conclude, impacts everything from basic cognitive functions to social skills and intelligence.
Dogs, as it turns out, aren’t particularly smart no matter how scientists have tried to measure it. In late 2018, a study that appeared in the journal Learning and Behavior plain and simply said that dogs aren’t exceptionally intelligent when measured against almost any animal. They compared dogs to wolves, cats, spotted hyenas, chimpanzees, dolphins, horses, and pigeons, and canines had no clear advantage over the other species in a range of cognitive abilities.
What we’ve learned about canines is that they seem to have a limited capacity for memorizing and recognizing verbal commands and physical gestures, and many of the skills they do possess that we tend to think make them “smart” actually aren’t exceptional when compared to other animals. In short, if you think your dog is a genius, scientists will tell you that’s not the case.
According to researchers at the University of Arizona though, if memory tests and self-control are markers of intelligence, then large dogs seem to take the cake when compared to their smaller counterparts.
Data was collected from more than 7,000 purebred dogs of 74 different breeds, including controls for genetic relatedness between breeds (ex: a miniature poodle and standard poodle) as well as whether or not those dogs had been trained. Basically, dogs were broken into a binary system that classified them as either “big” or “small,” all to identify if there was a strong relationship between estimated absolute brain size and intelligence. Simply put, does a larger dog and likely larger brain translate to greater intelligence?
The tests the UA researchers used to measure and find all this were actually pretty simple and they were all conducted by citizen scientists in their own homes, collecting the results from dognition.com, a website developed to give dog owners instructions for testing their dogs’ abilities through game-based activities. In order to test short term memory, they would hide a treat in view of each dog underneath one of two plastic cups. For each individual test, they would wait 60 seconds (one minute), 90 seconds, 120 seconds (two minutes), or 150 seconds. At that point they would release their dog and allow them to retrieve the treat, observing how well the canine remembered exactly where the treat was.
"When we test dogs on those sorts of tasks, where they have to exert self-control over not stealing something or they have to remember where something is hidden, the larger brained dogs seem to do better than smaller brained dogs," said Daniel Horschler, a UA doctoral student and one of the study’s researchers.
Another test created for self-control again used treats, although this time they weren’t hidden. Here, the treats were placed right in front of a seated dog with owners forbidding their pet from snatching it right up. The owner’s job was then to sit and watch their dog, cover their eyes as if they weren’t paying attention, or to turn away from their dog completely, waiting to see how long it would take their pet to cave in. In this test, the larger dogs were simply able to resist that urge to snatch their treat for longer periods than smaller dogs.
So what did researchers conclude from all this, aside from the simple “larger dogs must be smarter”? Well, they believe determining which dogs possess greater “executive function” can help us understand which types of dogs are better suited for jobs and tasks like working as service dogs, guide dogs, or even which dogs can detect drugs.
“Our results suggest that evolutionary increases in brain size are positively associated with taxonomic differences in executive function, even in the absence of primate-like neuroanatomy,” they concluded. “These findings also suggest that variation between dog breeds may present a powerful model for investigating correlated changes in neuroanatomy and cognition among closely related taxa.”
According to Horschler, there’s still room to hypothesize why a larger brain would somehow equate to greater intelligence in dogs. The largest animal species are not necessarily always the smartest in the world, comparatively, for example. “We think of it as probably a proxy for something else going on, whether it’s the number of neurons that matters or differences in connectivity between neurons. Nobody’s really sure yet, but we’re interested in figuring out what those deeper things are,” Horschler added.
Next up, Horschler says he’d like to conduct a similar study within specific breeds. While this study accounted for the miniature poodle and standard poodle control, a future study could actually compare cognition between the two directly. Since many “miniature” and “standard” variations within the same breed are more or less the same genetically, size tends to be the only variable between many of these types of dogs.
“I’m really interested in how cognition evolves and how that arises biologically,” Horschler says. “We’re coming to understand that brain size is in some way related to cognition, whether it’s because of brain size specifically or whether it’s a proxy for something else.”