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① The dog IQ test results show that even the average dog has the mental abilities of a 2-year-old child. The finding is based on a language development test. It shows that, like a 2-year-old child, average dogs can learn 165 words, including signals and gestures. And dogs in the top 20% in intelligence can learn 250 words.
② While dogs ranked with the 2-year-olds in language, they would do better than a 3-or 4-year-old in basic arithmetic. In terms of social smarts (智慧) , dogs may do even better. The social life of dogs is much more complicated, much more like that of human teenagers at that stage. They are interested in who is moving up in the group and who is having a relationship with whom", said Coren, an expert on dogs.
③ To get inside the brain of man's best friend, scientists are modifying tests for dogs that were firstly developed for children. In an arithmetic test, dogs watch as one treat and then another treat are being placed behind a screen. When the screen gets lifted, the dogs will expect to see two treats. But suppose the scientist takes away one of the treats, or adds another, so the end result is one, or three treats. “Now we're giving him the wrong equation (等式) which is one plus one equals one or three", Coren said. Sure enough, studies show that the dogs get it. "The dog acts surprised and stares at it for a longer period of time, just like a human kid would", he said.
④ Like small kids, dogs also show some basic emotions, such as happiness and anger. But more complicated emotions, such as guilt (负罪感) , are not something dogs can feel. And what humans once thought was guilt of a dog was found to be fear.