阅读理解

　　Dogs, like people and monkeys, seem to have a sense of fairness．

　　In the reward experiments, Friederike Range experimented with dogs that understood the command“paw”, to place their paw in her hand．The dogs were asked to shake hands and each could see what reward the other received．When one dog got a reward and the other didn't, the unrewarded animal stopped playing．When both got a reward all was well．Range said she wasn't surprised at the dogs' reaction, since wolves are known to cooperate with one another and appear to be sensitive to each other．Modern dogs are descended from wolves．Next, she said, will be experiments to test how dogs and wolves work together．“Among other questions, we will study how differences in emotions(情绪)influence cooperative(合作的)abilities,”she said．

　　But the dogs didn't seem to care whether the reward was sausage or bread．One possibility, they said, is that daily training with their owners overrides(比……优先)a preference．And the dogs never rejected the food, something that primates had done when they thought the reward was unfair．

　　Clive Wynne, a professor in the University of Florida, isn't so sure the experiment measures the animals' reaction to fairness, which means that individuals are responding negatively to being treated less well．But the researchers didn't do a control test that had been done in monkey studies, in which a preferred reward was visible but not given to anyone．In that case the monkeys went on strike because they could see the better reward but got something lesser．In dogs, he noted, the quality of reward didn't seem to matter, so the test only worked when they got no reward at all．However, Wynne added, there is“no doubt in my mind that dogs are very, very sensitive to what people are doing and are very smart．”