Chimpanzees are able to quickly identify the faces of other chimpanzees and human adults and babies from among a group of objects, finds a paper published in Scientific Reports this week. The results suggest that chimpanzees use a similar holistic process to humans when searching for faces.
Masaki Tomonaga and Tomoko Imura carried out a series of visual search tasks involving three chimpanzees named Chloe, Pendesa and Ai. In the first experiment, the chimpanzees were trained to find the picture of a chimpanzee face, a banana, a car and a house from among a number of different objects. The authors found that the chimpanzees could detect the face quickly and readily, but their ability to detect faces was significantly hampered when the face was inverted. This may suggest that spatial configuration or a combination of facial features allow chimpanzees to accurately identify faces.
In subsequent experiments, Tomonaga and Imura found that the chimpanzees could efficiently search for and find the faces of human adults and babies but were unable to identify monkey faces. The authors suggest that this may result from long-lasting social experiences with human adults.