Monkeys don’t like selfish people, not even when they tempt the animals with delicious food.
According to a study published in the journal Nature Communications last week, monkeys may judge others just like humans do. Researchers found that the primates consistently avoid accepting treats from humans that come off as selfish.
(More: Chimps Can Play Fair, Too)
In the study, seven highly social and cooperative capuchin monkeys watched two actors interact. The two people either helped or refused to help the other open a jar with a toy inside. They then offered a free treat to the monkeys, which were trained to accept food from only one. The capuchins showed no preferences between the two people when help was given but consistently turned down food from the person who was available to help others but declined to do so.
Kiley Hamlin, a developmental psychologist at the University of British Columbia in Vancouver, Canada, explained to Scientific American that the monkeys took the explicit refusal to help as a sign of dangerousness. According to CBSNews, that ability to detect undesirable personalities could be crucial to the monkeys’ survival. Wild capuchins depend on cooperation. Choosing the wrong partner probably means that they lose at the beginning.
It is not just capuchins that can recognize unfavorable traits. Similar behaviors have been seen in chimpanzees and in 3-month-old human infants. Hamlin said the Capuchin study may indicate that this ability has ancient evolutionary roots, noted Scientific American.
According to CBSNews, James Anderson, lead author of the study and a primatologist at the University of Stirling in Scotland, is now studying what Capuchins think of people who over-help others. He told CBSNews he wants to know if monkeys can form a positive impression of a person who behaves generously.