If you thought Rover or Sparky was smart, think again: Chaser just took him to school.
A border collie named Chaser has learned the names of 1,022 individual items -- more than any other animal, even the legendary Alex the parrot. But it's all in a day's work for these researchers.
Psychologists Alliston Reid and John Pilley of Wofford College in Spartanburg, S.C., wanted to test if there was a limit to the amount of words a border collie could learn, so they taught Chaser the names of hundreds of toys, one by one, slowly and patiently, for three years.
"We put in a lot of work on it," Pilley said in a conversation with FoxNews.com. While border collies are an especially smart breed, he said, the research doesn't allow them to conclusively call it smarter than, say, pit bulls or dachshunds.
"We can't say anything definitive about this, but there is agreement among breeders," he said, citing decades of breeding for herding that makes the dogs particularly attuned to learning words. "The hypothesis is that they do have a special propensity to language, they listen to the farmer."
Pilley stressed that the training technique more than anything resulted in the incredible skills of the dog.
"In the first experiment where we talk about the learning of proper nouns, the procedure we use is one where she was taught in a way that she couldn't fail," Pilley said. "We would place the object right on the floor, somewhere the dog couldn't miss."
Then after a period of several months, Pilley and Reid would work with a different object, slowly training the dog on each one.
"Most people when they try to teach a dog, they put too many objects on the ground. That's called simultaneous training," Pilley explained. "Our method was a successive technique."
The pair regularly tested Chaser on her vocabulary by putting random groups of 20 toys in another room and having her fetch them by name. Chaser, now 6, never got less than 18 out of 20 right, in 838 (!) separate tests over three years.
It takes 16 plastic tubs to hold all the toys.
Watch Pilley give Chaser some impressively complex commands -- combining three verbs with three nouns -- in the video below. She understands the verbs “nose,” “get” and “paw.” Her reward is playtime with “Blue,” a little ball she chases across the room. For a whole collection of Chaser videos, click here.
She learned common nouns that represented categories, such as “ball,” and she learned to infer the names of objects by their association with other objects.
Rico the border collie, from the Max Planck Institute in Leipzig, Germany, was previously top dog — he had a vocabulary of about 200 words. Chaser’s feats are chronicled in the journal Behavioural Processes.
Popular Science contributed to this report.