Gorillas and chimps in a mirror.

Most humans recognize themselves in a mirror, but this ability requires learning about mirrors. Young babies do not know that they are looking at their own reflection; at first, they react to their image as if it were another baby. They smile and vocalize toward the little playmate, try to touch it, and look or crawl behind the mirror to find it. Into her second year, the infant explores the visual properties of the mirror more intensely: pulling faces, clowning around, and testing the continencies of the mirror all contribute towards the realization that she is looking at an image of herself. By the age of 24 months, most infants show correct use of the mirror to investigate their appearance, checking their hair, looking at their tongue or inside their mouth, or noticing a mark on their face that can only be seen in the reflection. Psychologists study the development of self-recognition in human infants because it tells them about early self-awareness. Researchers have also investigated self-recognition in other species, especially monkeys and apes.𝗜𝘁 𝘀𝗵𝗼𝘂𝗹𝗱 𝗯𝗲 𝗿𝗲𝗺𝗲𝗺𝗯𝗲𝗿𝗲𝗱 𝘁𝗵𝗮𝘁 𝗼𝘂𝗿 𝗰𝗹𝗼𝘀𝗲𝘀𝘁 𝗽𝗿𝗶𝗺𝗮𝘁𝗲 𝗰𝗼𝘂𝘀𝗶𝗻𝘀, 𝘁𝗵𝗲 𝗴𝗿𝗲𝗮𝘁 𝗮𝗽𝗲𝘀, 𝗮𝗿𝗲 𝗴𝗲𝗻𝗲𝘁𝗶𝗰𝗮𝗹𝗹𝘆 𝗮𝗻𝗱 𝗮𝗻𝗮𝘁𝗼𝗺𝗶𝗰𝗮𝗹𝗹𝘆 𝗺𝗼𝗿𝗲 𝗹𝗶𝗸𝗲 𝗵𝘂𝗺𝗮𝗻𝘀 𝘁𝗵𝗮𝗻 𝗮𝗿𝗲 𝗺𝗼𝗻𝗸𝗲𝘆𝘀, 𝗮𝗻𝗱 𝘂𝗻𝗹𝗶𝗸𝗲 𝗺𝗼𝗻𝗸𝗲𝘆𝘀, 𝘁𝗵𝗲𝘆 𝗱𝗼 𝗻𝗼𝘁 𝗵𝗮𝘃𝗲 𝗮 𝘁𝗮𝗶𝗹. Convincing evidence for self-recognition exists only for great apes (chimpanzees, bonobos, gorillas, orangutans), although strong and plausible claims have also been made for a few non-primate species, namely elephants and dolphins. Like human babies, monkeys and apes first react to their own reflection as if they were looking at another, unfamiliar member of their species. However, this strange individual only imitates; it doesn’t interact normally, and it sometimes suddenly appears then disappears from view. The reflection clearly perplexes the viewing monkey or ape, and the behavioral reactions it elicits depend on factors such as species, age, sex, social status, and presence of others. For example, infants might approach their reflection as they would approach a potential play partner, whereas older individuals might see the stranger as a threat, giving rise to feelings of tension, and even aggressive attacks. Studies of great apes in captivity have documented that with increasing exposure to their reflection, tension, anxiety, and aggression decrease, and the individual starts to compare its own movements with those of the reflection. Eventually this leads to spontaneous mirror-guided self-directed responses, when the individual makes use of the mirror to explore parts of its body that it cannot see directly, such as the ano-genital region, or inside the mouth. These new behaviours suggest the transition from perceiving the reflection as “other” to perceiving it as “me” Self-recognition is often confirmed in a test in which the ape is secretly marked on a part of the face (e.g, forehead, ear) that can only be seen in a mirror. Positive evidence of self-recognition indicates that some aspects of sense of self are shared between great apes and ourselves. In contrast to the great apes, monkeys show no convincing signs of self-recognition All scientific studies of mirror-image reactions in great apes have been done on captive individuals or groups in zoos, sanctuaries, or laboratories. Nine years ago, Xavier HUBERT-BRIERRE opened up new possibilities by installing several large mirrors throughout a forest zone in Gabon, in the home range of a completely wild community of chimpanzees and at least one group of gorillas, as well as many other species. Thanks to video-traps set up near each mirror, Xavier has captured the behavioral reactions of many animals upon encountering these mirrors. The forest is a dangerous environment, not least because intruders of the same species might signal possible invasion, injury, and even death. Many of Xavier’s videos show chimpanzees and gorillas responding to their reflections as if they were under threat, displaying and charging at the mirror, sometimes violently. With repeated exposure to the mirrors, however, for many individuals the social overtones of the reflection diminish, and in the secure presence of other, calm, group and family members, individuals start to explore the reflection more quietly and carefully. This change in attitude and behaviour, in turn, might eventually lead to the first great apes in the wild to have an accurate mental representation of their own visual appearance.