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Uma experiência extraordinária pôs a prova a capacidade dos cães em  perceber a comunicação humana. Primeiro, um Border Collie observou o dono a mostrar-lhe uma réplica miniatura de um brinquedo de corda. A seguir, foi ao quarto ao lado e trouxe um brinquedo exactamente igual em tamanho maior para o dono. Fantástico! 

"Go FETCH!!!! 

Dogs are lousy conversationalists and can’t write worth a lick. But don’t sell the family pooch short when it comes to grasping subtle references in human communication, a new study suggests. Border collies quickly realize that their owners want them to fetch a toy from another room when shown a full-size or miniature replica of the desired item and given a command to “bring it here,” say biological psychologist Juliane Kaminski of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and her colleagues. Even a photograph of a toy works with some dogs as a signal to fetch that toy from an unseen location, the researchers report in an upcoming issue ofDevelopmental Science. 

Three dogs already trained to fetch objects succeeded on both replica tasks right away. Two untrained dogs got the hang of replica requests after a bit of practice. “The most reasonable interpretation of dogs’ success in the replica tasks is that they understood that by showing a replica, a human was trying to communicate something to them,” Kaminski says. Dogs evolved a feel for how people communicate as a result of living in human settlements for thousands of years, she proposes. Earlier studies have found that chimps, dolphins and other nonhuman animals have great difficulty retrieving objects after being shown replicas of those objects, even after many trials. The new study shows that the border collies interpreted a fetch request as meaning that they should find a toy resembling that held by owners, remarks psychologist Alexandra Horowitz of Barnard College in New York City. It’s not clear that the dogs’ ability to see a replica of an object as a stand-in for that object in a fetching situation translates into a general capacity for knowing that some items can be used to represent others, Horowitz says. Among the five dogs studied by Kaminski’s group, one trained and one untrained animal regularly retrieved toys depicted in photographs displayed by their owners. The remaining dogs did poorly on this task. Dogs have little experience with photographs and may have difficulty treating a photograph of an object as a separate representation of that object, at least without training, Kaminski posits. Her team conducted experiments at each dog owner’s residence in Germany. A researcher put eight dog toys on the floor of a room and then joined the owner and the dog in an adjacent room. Next, the owner requested a particular toy by showing the dog one of three visual cues — an identical replica, a miniature replica or a photograph of the toy — and saying “bring it here.” Dogs searching for a toy in the adjacent room could not see their owners or the researchers. Over eight trials, trained dogs nearly always fetched toys that corresponded to identical and miniature replicas. One untrained dog successfully used miniature replicas to retrieve toys, but neither untrained dog did well with identical replicas right away. In a second round of trials with identical replicas, untrained dogs’ performance improved. In another experiment, the three trained dogs were shown a full-size photograph of a toy and selected from among four toys and full-size photographs of them mounted on small stands. Two dogs usually retrieved what they had seen, with one favoring corresponding toys and the other preferring corresponding photographs."

in: science news online edition