Self-awareness may be beyond primates in the wild.
Chimps, organutans and other species faced with a mirror react to a dot on their face in the lab, a widely used measure of self-awareness. But while baboons in Namibia exposed to mirrors find the reflective glass fascinating, they don’t respond to dots placed on their faces, researchers report in the January Proceedings of the Royal Society B: Biological Sciences. The result could indicate that lab responses to mirrors are a result of training — and that self-awareness might exist on a spectrum.
“Psychological self-awareness is this idea that you as an individual can become an object of your own attention,” says Alecia Carter, an evolutionary anthropologist at University College London. It’s a hard concept to measure in other species, in part, she notes, because “it’s also difficult to imagine not having that kind of self-awareness.”
One measure of self-awareness is the mark test. An animal sits in front of a mirror, and a mark is placed somewhere they normally cannot see, such as on the face. If the animal recognizes themselves in the mirror, and the mark as out of place, the animal will respond to the mark.
Chimps, orangutans and bonobos have “passed” the mark test in the lab, while primates that are not great apes, such as rhesus macaques, have mastered it only after training. Other species, such as Asian elephants, dolphins and even a fish called the cleaner wrasse, have also responded to the mark test.
But no one had tried a large-scale mirror test with fully wild animals. Carter and her colleagues set up two mirrors for five months at the Tsaobis Nature Park in Namibia. The mirrors were placed by water points favored by two troops of chacma baboons (Papio ursinus). When a baboon stared into the mirror, a scientist would shine a laser pointer onto the animal’s cheek or ear and record the reaction. The researcher would also shine the laser pointer on spots on the arms or legs that the baboon could see, to make sure the animal reacted to the dot.
The baboons adored their reflective toy. “They were lining up to sit in front of it,” Carter says. They also responded to the laser pointer alone — when scientists put the dot on the visible body parts of 91 baboons, the monkeys pawed at it 64 percent of the time. But only one of the 51 baboons that gazed in the mirror while a laser shone on their face or ear responded even once. A few, Carter notes, peered at the mark in the mirror, but did not reach for their own face. The results suggest that monkeys might not pass the mark test without experience in laboratory conditions, Carter says.
It’s “the first systematic study of the mirror self-recognition question in wild primates,” says James Anderson, a primatologist at Kyoto University in Japan, and it confirms that non-ape monkeys do not recognize themselves in a mirror. In the lab, trained rhesus monkeys voluntarily use mirrors to examine their genitals. But the baboons showed no sign of using the mirror on their primate privates, Anderson says, further confirmation that they may not see the monkey in the mirror as themselves.
The baboons might, however, not see the mark as being on their face, says Masanori Kohda, an animal sociologist at the Osaka Metropolitan University in Japan who has been studying the mark test in cleaner wrasse. “The laser pointer mark does not follow one’s movements precisely,” he says. The baboons might see the mark as projected onto the mirror instead of their own faces.
The baboons did appear to understand the mirror depicted the scenery behind them, and that the image in the mirror was not another baboon. This intermediate understanding could indicate that self-awareness exists on a spectrum, says Lindsay Murray, a psychologist at the University of Chester in England. In humans, self-awareness arises gradually — only 65 percent of children show the skill by age two. “An increasing number of researchers are now using this gradualist framework,” she says.
After all, while humans place a lot of importance on self-awareness, Carter notes, that is how we experience the world, not how other animals do. “Baboons are doing very well without possibly having a concept of self-awareness,” she says. “And I’m not entirely sure what they could get out of it.”