Rico, the border collie, was taught to retrieve different objects by his owners, who placed various balls and toys around their apartment and asked Rico to fetch specific ones. Rico gradually increased his vocabulary to about 200 words that he could match to objects. To make sure Ricos owners werent giving him subconscious cues that helped him find the right item, Julia Fischer and her colleagues at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, tested Ricos knowledge in a lab, where he retrieved 37 out of 40 items correctly. "Ricos vocabulary size is comparable to that of language-trained apes, dolphins, sea lions, and parrots," the authors write in their report, published today in the journal Science.
The team then tested Ricos ability to employ fast mapping, a neurological process that toddlers use to quickly guess the meaning of new words. The researchers put an unfamiliar object in a room with other things he did know and, without teaching Rico the name of the novel item, asked him to get it. Seven times out of 10 he returned with the correct object.
Four weeks later, the scientists tested Ricos ability to recall what he had learned. The objects that he had seen only once during the previous experiment were placed among eight other things, some familiar and some completely new. In this trial, Rico retrieved the correct item three out of six times, a feat of learning never before seen in a dog. Ricos performance was comparable to that of a three-year-old toddler, the scientists observe.
Fischer and her collaborators note that theyre not sure whether Rico is exceptionally smart or exceptionally well trained, but they hope they can use this experiment to further probe how the brain learns to understand words. Ricos powers of comprehension, they say, show that the processes the brain uses to discern words are not the same as those used to produce speech. Says Fischer: "You dont have to be able to talk to understand a lot."