Most humans expect to receive fair treatment. A recent study shows that monkeys may feel the same way. This is the first time scientists have seen this kind of behavior in animals. Scientists chose monkeys for the research because monkeys have close relationship with each other and they also have good teamwork. Sarah Brosnan, the leader of the research, put female monkeys in pairs. The researchers trained the monkeys to exchange a small rock with them. "That may sound simple, but not very many animals are willing to give things away." Says Brosnan. When a monkey exchanged a rock with the researcher within 60 seconds, she received a reward. Usually, the reward was a piece of cucumber. The partner of each monkey who made an exchange also received a reward. Sometimes the partner got the same reward (a piece of cucumber), but other times the partner received a better reward (a grape). The researchers were surprised at how the monkey _ to the unfair treatment. When a monkey saw her partner get better treatment, she was unhappy. The monkeys did not want to continue the test or eat the cucumbers they received. Some monkeys even threw their food at the researchers. Bronson's research suggests that monkeys do not like unfair treatment. However, as Brosnan explains, "We don't know how monkeys learn to dislike being treated unfairly. But that opens up a whole new research field." Scientists will continue their research. A recent study shows that monkeys   _  .
expect to receive fair treatment behave differently from humans have no teamwork in their life have bad relationships with each other