In a remarkable new study, scientists have discovered that great apes apparently possess an understanding of what others are thinking. This was once thought to be a uniquely human trait until this new evidence.

An international team of researchers found that chimpanzees, bonobos, and orangutans possess this ability, which is known as "theory of mind," or the ability to know that others have a different point of view of the world.

During experiments, scientists put the theory of mind to the test on primates. They found that the animals understood that others could even have false beliefs.

Past studies have shown that apes can understand others' perspectives. However, this is the first study that indicates that primates appear to understand that others can possess false beliefs. This concept is usually developed in humans around four to five years old.

In this study, the experiments involved apes watching 40-second movies showing someone in a King Kong costume playing tricks on another person. The person watches King Kong hide in a rock or box and a hay bale. When the person leaves, King Kong transfers from the bale or to the rock to hide again.

This suggests that the person did not know that King Kong moved from its original hiding place. However, the ape watching this short film does. When the person returns, the ape anticipates and looks at the rock, which the ape knows that this is the last place the person knows where King Kong was hiding.

According to the co-author of the study, psychologist Fumihiro Kano from the University of Kyoto, this anticipation from the apes is evidence that they grasp the concept of others' false beliefs which is a critical factor in cognition.

According to another co-author of the study, Christopher Krupinye from the Max Planck Institute, apes show some understanding of others' actions even if they know they are acting based on wrong information.

Researchers suggest that this kind of cognitive skill is the core of a lot of sophisticated human behavior that is crucial in "cooperative context in culture and communications."

This new study has been published in the journal Science.