Humans aren’t the only ones who can tell when someone’s beliefs don’t match reality.
New research on chimpanzees, bonobos and orangutans suggests our primate relatives may also be able to tell when that someone’s beliefs may differ from reality. They also have been found to use this knowledge in their choice of actions.
The bonobo in the upper left corner sips juice and watches a video while researchers track his gaze, shown in red. The video is designed to test apes’ ability to recognize when others hold false beliefs. Courtesy of Fumihiro Kano, Kyoto University.
The findings suggest the ability is not unique to humans, but has existed in the primate family tree for at least 13 to 18 million years, since the last common ancestors of chimpanzees, bonobos, orangutans and humans.
The study, led by researchers at Duke University, Kyoto University, the University of St. Andrews and the Max Planck Institute for Evolutionary Anthropology, has been published in the journal Science.
As humans, we tend to believe that our cognitive skills are unique, not only in degree, but also in kind. Research like this shows that the more closely we look at other species, the clearer it becomes that the difference is one of degree. The researchers examined three different species of apes, finding they were able to anticipate that others may have mistaken beliefs about a situation.
The capacity to tell when others hold mistaken beliefs is seen as a key milestone in human cognitive development. We develop this awareness in early childhood, usually by the age of five. This step marks the beginning of a young child’s ability to fully comprehend the thoughts and emotions of others—what psychologists call theory of mind.
These skills are essential for getting along with other people and predicting what they might do. They also are the foundation our ability to trick people into believing something that isn’t true. Moreover, the inability to infer what others are thinking or feeling is considered an early sign of autism.