But new research on chimpanzees, bonobos and orangutans suggests our primate relatives may also be able to tell when something is just in your head.
The study, led by researchers at Duke University, Kyoto University and the Max Planck Institute for Evolutionary Anthropology, is scheduled to appear Oct. 7 in the journal Science.
The capacity to tell when others hold mistaken beliefs is seen as a key milestone in human cognitive development. Humans develop this awareness in early childhood, usually before the age of five. It marks the beginning of a young child’s ability to fully comprehend the thoughts and emotions of others—what psychologists call theory of mind.
Such skills are essential for getting along with other people and predicting what they might do. They also underlie our ability to trick people into believing something that isn’t true. An inability to infer what others are thinking or feeling is considered an early sign of autism.
“This cognitive ability is at the heart of so many human social skills,” said Christopher Krupenye of Duke, who led the study along with comparative psychologist Fumihiro Kano of Kyoto University.

Read more at: http://phys.org/news/2016-10-apes.html#jCp