Washington / Atlanta - Chimpanzees can act selflessly and help each other. But how often do they actually do that? Researchers argue about this question. New results suggest that the animals are more social and disinterested than previously thought.
Researchers at the Yerkes National Primate Research Center in Atlanta had tested chimpanzees: the animals were able to choose between differently colored coins. One color only fed them food, the other color provided the food to both them as well as to a fellow-dog sitting in the side cage. "With a free choice between a selfish and a social decision, the chimpanzees overwhelmingly favored the one that also benefited their partner," the researchers report in the journal "Proceedings of the National Academy of Sciences" .
This is in contrast to many previous experiments, according to which chimpanzees are at best reluctant altruists who reacted only selflessly. "I have always been skeptical about previous negative results," says study director Frans de Waal, a long-time chimpanzee researcher, both at the Freiland and Yerkes Research Center. "This study confirms the prosocial nature of chimpanzees with a test that is better suited to the type of behavior."
It is well known that monkeys helped each other in the wilderness and showed different forms of empathy. Now this disinterestedness could also be demonstrated under controlled conditions in the laboratory. According to the researchers, this also shows that altruism is not a human reinvention. Instead, this property existed already before the separation of chimpanzee and man about six million years ago.
Excessive begging is not good
To test how altruistic chimpanzees act, there are two standard tests: In the "help" test, a coworker sitting in the secondary cage does not get to his food. The test chimpanzee can help him by giving him the food or a tool. In these tests, chimpanzees have proved to be quite helpful - especially when the species is actively making a name for itself.
In a second standard test, the monkeys must choose between two equally advantageous options. Only one of them brings food to their experimental partner. Both monkeys can not communicate directly with each other in this experiment. In these tests the chimpanzees failed so far. According to de Waal and his colleagues, however, this could be due to the complicated design of the test apparatus and the lack of contact between the animals. Therefore, you have simplified this test accordingly.
The researchers tested seven chimpanzee females, who were in contact with one of the neighbors. Before the test chimpin was a container with plastic coins in two different colors. She could exchange the coins with a human banter for a banana as a reward. However, one of the two colors also received a banana.
"One by one chose the option, which provided food for both her and her partner," the researchers report. The chimpanzees did this even when their peers were quiet. Excessive begging on the part of the experimental partner proved to be counterproductive. This therefore disproves theories, according to which chimpanzees act disinterestedly only in oppression and pressure.
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