Although we are the only species that examines our reflection in a mirror every day, we are not the only creatures that recognize ourselves on reflective surfaces.

Scientists have tested mirror recognition in a wide range of species, starting with chimpanzee studies.pantroglodytes), was published in 1970. Animals ranging from ants to mantas to African gray parrots (Psittacus beritacus) were carefully examined for signs of self-consciousness when shown a mirror. He realizes that he is looking after a small handful of himself. Many don’t do this. And some showed unconvincing behavior.

These mixed results have led researchers to debate the test’s usefulness and how it helps scientists understand animal cognition.

“Many animals can’t get through,” primatologist Frans de Waal of Emory University told LiveScience. De Waal performed self-awareness tests on capuchin monkeys but failed. “They need to check the visual cue on their own in front of a mirror, without any training or reward. It must be spontaneous. Many of the claims in the literature do not fit this description.”

So which animals were tested?

During experiments with chimpanzees in 1970, four chimpanzees were anesthetized and their faces were marked with red paint. When they woke up, they examined the areas marked on the mirror, indicating that they understood that they were looking at themselves.

An assessment test is now considered the most convincing evidence of mirror self-awareness. Other great apes were also tested. In a 1973 study, orangutans recognized themselves and even recognized markings on their bodies. In a study conducted in 1994, it was observed that bonobos examined parts of their bodies that they could not see in the mirror. The results for gorillas were less satisfactory.

Monkeys often perceive their reflection as another animal, but some controversial studies have shown that some species can identify themselves after intense training.

This is also true for other animals, casting doubt on the results of these studies. “Does the training process invalidate the results of mirror testing for species that need it?” wonders cognitive psychologist Ellen O’Donoghue, who studies pigeon learning at Cardiff University in the United Kingdom. Critics of tests that use training exercises argue that such learned behaviors are not reliable evidence of self-awareness.

The only other land mammal that passes the test convincingly is the Asian elephant (Elephas maximus) from the Bronx Zoo. Research on dolphins shows that they can also distinguish their own reflections. A 1995 study using video instead of mirrors and a 2001 study using mirrors showed that dolphins use their images to discover marks made on their bodies.

Researchers studying Eurasian magpies in 2008 (Pica Pica) found the first evidence that non-mammals have the ability to recognize themselves in a mirror. pigeons too passed the test – but only after a period of rigorous conditioning. And in 2022, wild Adelie penguins (Pygoscelis adeliae) also showed signs of self-awareness in the mirror, although they did not respond to the colorful bibs worn around their necks instead of body tags.

Testing on lower animals is particularly controversial. A 2015 study suggested that ants may have some self-awareness as they attempt to remove blue paint from their heads by looking at their reflections. Two studies have shown that fish can recognize themselves. One 2016 study found that manta rays appeared to examine themselves and blew bubbles when shown in a mirror. However, no evaluation tests were performed. 2019 experiment with wrens (Labroides dimidiatus) found that they were trying to remove the paint marks on the bottom after seeing them in the mirror.

The fact that these supposedly more primitive organisms pass the mirror test, while some of the most intelligent non-human animals, including African gray parrots, fail, casts doubt on its usefulness. It is not clear whether these studies demonstrate a true sense of self in the human mind or merely point to complex body awareness.

“The mirror test may index an aspect of self-awareness,” O’Donoghue told LiveScience. “There is a tendency to look at self-awareness as all or nothing. This is probably not true. “It’s probably more of a phase.”