Apes continue to show additional similarities with their human counterparts. The theory of mind has been observed to some degree in these mammals for the first time, even though it was believed only humans had the ability to predict others’ behavior as if they could actually read their minds.

A new study published in Science revealed that bonobos, chimpanzees, and orangutans appear to form ideas about what others, including humans, are thinking. Human communication is not very easy, but it would be extremely difficult to accomplish if we didn’t have the ability to make inferences about others’ desires, feelings, and beliefs. All of this allows us to predict the behavior of those around us based on previous actions and current body language.

The theory of mind has been observed in apes for the first time. Image credit: Rise of the Planet of the Apes. Image credit: Rise of the Planet of the Apes.

“Decades of research with our closest relatives — chimpanzees, bonobos, gorillas, and orangutans — have revealed that great apes do possess many aspects of the theory of mind,” study author Christopher Krupenye of the Max Planck Institute wrote for the Conversation, the Washington Post reported.

He added that great apes have the ability to recognize the intentions and goals behind the actions of other individuals, as well as the skill to identify those features of the environment others can observe or be aware of.

An international team of researchers studied more than 40 chimpanzees, orangutans and bonobos at Zoo Leipzig in Germany and Kumamoto Sanctuary in Japan. The experiment, which was not invasive, involved eye-tracking technology as researchers aimed to find out what the apes were interested the most in when watching videos of their species interacting with humans.

In one scene, a human actor saw King Kong hide a stone within one of two boxes. He was trying to search for the stone, but the great ape moved it to another spot and then removed it completely while the actor was away. When he came back, he had the false belief that the stone remained within one of two boxes, where it originally had been.

By using a special camera that recorded the apes’ gaze patterns, the researchers were able to map them onto the video and find out where the animals were looking as they watched the scenes. The team realized that the apes did anticipatory looking. This means that their gaze went to the spots where they anticipated an action was about to take place. Their tendency helped the investigators know what the animals expected the human actor to do once he had returned to search for the stone.

A ‘genuine breakthrough’

The researchers were surprised to see that the apes consistently looked to the location where the actor mistakenly assumed the stone to be, as their gaze appeared to predict the actions performed by the actor even before he showed any signs of the spot he was headed to, in order to find the stone. Humans do the same, and that is what a false belief recognition means.

Frans de Waal, from Emory University, wrote in a commentary on the study that the research was a “genuine breakthrough.” He was not linked to the study but acknowledged that their findings clearly showed that humans are not as superior as many people think. He also noted that the scientific community should always be open-minded about the mental capacities of animals.

Apes might have the ability of predicting others’ behaviors. Image credit: Rise of the Apes.

Further research is needed to deeply understand the apes’ ability to interpret what’s going on in the minds of other individuals. Should the theory of mind be truly present in them, it probably existed already in the last evolutionary ancestor that people shared with the other apes. Based on that, the skill of recognizing others’ false beliefs would have evolved 13 to 18 million years before the Homo sapiens appeared.

Source: The Washington Post