Chimps can spot faces just like humans

Chimpanzees can quickly identify the faces of other chimps, as well as those of human adults and babies, scientists have found.
Humans are wired to pay special attention to faces and can detect pictures of faces effortlessly when they are mixed with pictures of other items.
Scientists have found that chimps, humanity's closest living relatives, also see faces differently than they do other items.
In the research, scientists first trained three adult chimpanzees named Chloe, Pendesa and Ai to find pictures of a chimp face, a banana, a car and a house among groups of other images on a touch screen.

The researchers found that the apes recognised the chimp face very efficiently.
"Chimpanzees very quickly find a face in the pile of various objects," said study lead author Masaki Tomonaga, a primatologist and comparative cognitive scientist at Kyoto University's Primate Research Institute in Japan.

However, the chimps' ability to detect a chimp face was significantly hampered when the face was upside down. This suggests that chimps may analyse faces holistically, like humans do, 'Live Science' reported.
In subsequent experiments, the scientists also found that the chimpanzees efficiently detected the faces of human adults and babies, but were unable to identify monkey faces.

The researchers suggest this gap may result from long-lasting social experiences between chimps and humans. Faces seen from the front were more easily detected than faces seen from the side, suggesting that eye-to-eye contact is important for chimps, just as it is in humans.
"Both humans and chimpanzees have developed a specialised ability for face processing," Tomonaga said.
"This implies that the face plays a very important social role in both species. These results are quite suggestive when considering the evolution of social intelligence. Both species may use facial information for their social lives in the same manner," Tomonaga said.

The study is published in the journal Scientific Reports.