Some dogs can classify their toys by function

"Co-author Claudia Fugazza of Eötvös Loránd University in Budapest, Hungary, likens this ability to a person calling a hammer and a rock by the same name, or a child understanding that "cup" can describe a mug, a glass, or a tumbler, because they serve the same function. "The rock and the hammer look physically different, but they can be used for the same function," she said. "So now it turns out that these dogs can do the same.""

"A dog will interpret the gesture as a directional cue, unlike a human toddler, who will more likely focus on the object itself. It's called spatial bias, and the team concluded that the phenomenon arises from a combination of how dogs see (visual acuity) and how they think, with "smarter" dog breeds prioritizing an object's appearance as much as its location. This suggests the smarter dogs' information processing is more similar to that of humans."

Certain dogs can memorize object names and extend those labels to new objects that share function despite differing appearance. Label extension is a cognitively advanced ability that typically requires years of intensive training in captivity, yet some dogs acquire it through natural play with their owners. The ability enables classification of toys by function, analogous to calling a hammer and a rock by the same name or grouping mugs, glasses, and tumblers as cups. Dogs interpret pointing as a directional cue (spatial bias), influenced by visual acuity and cognition, with some breeds prioritizing appearance similarly to humans. Head length correlates with visual acuity.

Read at Ars Technica