Several experiments showed that the animals are much more cautious when it comes to intruders, and to have a bad prejudices about them. The survey was conducted on the uninhabited island of Cayo Santiago Puerto Rican in which live many different kinds of monkeys.
Neha Mahajan, a student at Yale University, led a team of psychologists who have studied the behavior of monkeys because these animals are very similar people, live in groups and build strong social ties.
Psychologists has long been known that the bias point of automatism, and that they are not even aware. Tests on monkeys have shown that biases such as "we " and "they" have their roots from ancient times.
Researchers followed a time in which the monkeys looked at the photos by their group and the monkeys that did not belong to that group. After several experiments, we found that the monkeys looked more photos of unknown but familiar faces.
To ensure that monkeys are not only curious, the researchers combined the photographs of monkeys who have recently left the group and those who have joined her.
During this experiment, the monkeys again looked more photos intruders, ie. those monkeys who left the group, although they were more familiar with the newcomers.
Monkeys are obvious differences made on the basis of whether the monkeys in the photos of their group members or not. Mahayana and her colleagues devised an experiment to discover whether animals have a negative attitude toward the intruders, and the newcomers. Then the group members with photos and intruders combine photos of attractive items such as fruit, and unattractive, such as spiders, writes Daily Mail.
When the photo of the group members combined with a photograph of fruit, or intruders with a photograph photographs spider monkeys are quickly lost interest. But when a photograph of members of the group paired with spider monkeys have long observed.
The researchers assume that the monkeys confused combination of right and wrong. This showed that the monkeys do not make a difference between group members and intruders, but also to link the members of your group with good things, and intruders with bad.
The magazine "Scientific American" (Scientific American) writes that the results of this study demonstrate the evolutionary basis of prejudice.