Tug or fetch? Some dogs sort toys by how they are used

“Where’s your red ball? Get your squeaky chicken!” Some dogs know their favorite toys by name. Now, it turns out that dogs with a knack for learning words are also capable of mentally labeling toys just by how they are used during play, a new study suggests. These dogs can even classify a new toy based entirely on its use, without any verbal or physical clues.

The findings, published September 18 in Current Biology, add to the growing list of compellingly complex cognitive activities at work in the canine brain.

“This work came about after a [dog] in another study not only generalized her own toys into categories like ball, rope and ring, but could also sort toys she’d never seen before into those categories,” says Claudia Fugazza, an animal-behavior researcher at Eötvös Loránd University in Budapest. “We wanted to test whether dogs could also classify a toy based strictly on how it is used during play rather than on shared physical traits.”

The specific dogs in question are known as gifted word learners: pet dogs, many of them border collies, famed for their extensive vocabulary of toy names learned spontaneously during at-home play. For the new study, Fugazza and her colleagues recruited 11 gifted word learners and their owners. Seven dogs ultimately completed the project.

The studies took place in each dog’s home environment. As a first step, owners played games labelled either “throw” or “pull,” basically fetch or tug-of-war, with their dogs using a range of toys — from squeakers to ropes to plushies — while naming the activity aloud. Toys were randomly assigned a category; their physical traits did not dictate their use.

Once the dogs successfully connected each toy to its spoken function, owners and dogs played either throw or pull with novel items, this time without the owners naming the activities aloud.

Finally, owners asked their dogs to “bring me a pull” or “bring me a throw” from the toy pile to test whether the animals would apply the labels to the new toys based solely on their play experience with the items. Correct picks of novel toys would suggest that the dogs were generalizing functional labels from the old to the new.

Overwhelmingly, they picked right. On average, from a pile including both old and new toys, the dogs selected the appropriate novel toy in 31 out of 48 trials despite never having heard the categories named aloud in reference to those items. Most “mistakes” occurred when a dog chose an old pull or throw toy whose label had been verbalized during earlier training.

Previous investigations into whether animals can categorize objects by function relied on heavily trained captive animals. “This is the first study exploring this cognitive skill in animals in their natural environment — in the case of dogs, at home playing naturally with their owners,” Fugazza says. Earlier research also didn’t untangle physical or other cues the dogs might be using from functional ones. The new study ensured that the dogs relied on only dynamic, social cues — how their owners played with a toy.

Looking to human infants for comparison, the dogs’ functional labeling skill is about on par with that of a toddler. “The fact that this learning happened [naturally], not in a lab with thousands of training trials, suggests that dogs’ ability to infer function from context is both more sophisticated and more ecologically valid than we’ve appreciated,” says Vanessa Woods, an evolutionary anthropologist at Duke University and director of a project called the Duke Puppy Kindergarten. “It demonstrates that dogs are not only memorizing labels but can also flexibly use them in a way that reflects deeper categorization.”

Future studies may explore what other mental categories the dogs can create and the brain mechanisms involved. “It’s exciting to see dogs recognizing, remembering, inferring,” Fugazza says. “It takes a lot of cognitive processing to do what they’re doing.” Based on the fact that her subjects were gifted word learners — her “ambassadors to understanding dog cognition,” as she calls them — Fugazza can’t say all dogs have this functional-labeling skill. “But I wouldn’t exclude that possibility.”