WASHINGTON (Reuters) - Monkeys can experience the joy of giving in much the same way as humans do, U.S. researchers reported on Monday.
Tests in capuchin monkeys showed the animals consistently chose to share food with another monkey if given the option, suggesting they are capable of empathy, the team at the Yerkes Research Center at Emory University in Atlanta found.
"They seem to care for the welfare of those they know," Frans de Waal, director of the Living Links Center at Yerkes, said in a statement.
His team tested eight female brown capuchin monkeys in pairs. They could choose a token that gave only themselves a treat or an option that rewarded both of them, called a prosocial option.
Either way, the first monkey got the same amount of food.
"Subjects systematically favored the prosocial option provided their partner was a) familiar, b) visible, and c) receiving rewards of equal value," De Waal's team wrote in their report, published in the Proceedings of the National Academy of Sciences.
"The fact the capuchins predominantly selected the prosocial option must mean seeing another monkey receive food is satisfying or rewarding for them," said de Waal.
"We believe prosocial behavior is empathy based. Empathy increases in both humans and animals with social closeness, and in our study, closer partners made more prosocial choices."
De Waal's team next will see whether giving is rewarding to capuchins because they can eat together or if the monkeys simply like to see the other monkey enjoying food.
"Capuchin monkeys spontaneously share food in both nature and captivity, and commonly sit next to each other while eating," the researchers wrote.
(Reporting by Maggie Fox, editing by Alan Elsner)