Be nice – or your dog may judge you. Both pets and monkeys show a preference for people who help others, and this might explain the origins of our sense of morality.Studies involving babies have previously shown that by the age of one, humans are already starting to judge people by how they interact. This has led to suggestions that children have a kind of innate morality that predates their being taught how to behave.Comparative psychologist James Anderson at Kyoto University and his colleagues wondered whether other species make social evaluations in a similar way.They began by testing whether capuchin monkeys would show a preference for people who help others. The capuchins watched an actor struggle to open a container with a toy inside.Then this actor presented the container to a second actor, who would either help or refuse to assist. Afterwards, both actors offered each capuchin food, and the monkey chose which offer to accept.
Monkeys and dogs judge humans by how they treat others