The self-awareness mirror test: what is it and how is it used in animals

Since time immemorial, anthropocentrism has led us to think that human beings are the only species capable of self-recognition and self-awareness. However, research has shown that this is not the case and that many other animals, such as dolphins, orangutans or elephants, could have this same capacity.

To study this phenomenon, the mirror test has been used, a test that, until now, has served to measure self-recognition or self-awareness in animals. And we say until now because in recent years, with the discovery that even ants or fish pass The test, part of the scientific community has questioned the validity of the test to measure this cognitive ability.

In this article we explain what does the self-awareness mirror test consist of and what are its limitations. In addition, we review the latest research on this interesting phenomenon.

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The self-awareness mirror test: what is it and what is it for?

The Mirror Test, developed in 1970 by Gordon G. Gallup Jr, is a test that measures the level of self-awareness and visual self-recognition. What determines the test is

whether an animal can recognize its own reflection in a mirror as an image of itself.

This test is quite simple: just put a mirror at the disposal of the animal and observe its behavior. When the animal becomes accustomed to the mirror, the researchers mark with an odorless dye a part of its body that cannot be seen without the help of the mirror. Thus, if the animal reacts consistently with being aware that the dye is in its own body, positive evidence of self-awareness is obtained.

Behaviors that indicate that the animal is able to recognize itself in its mirror image include turning and adjusting the body to better see the mark in the mirror, or touch the mark with your own body or with a finger while looking at the mirror. The animals that until recently had passed the mirror test have been: chimpanzees, bonobos, orangutans, dolphins, elephants, common pigeons and, of course, humans.

However, recent research has found that even some species of ants and fish have reacted positively to the self-awareness mirror test, which has generated great controversy in the scientific community, dividing opinion among those who believe that the test is not valid or conclusive and who believe that the implications that it may have for the study of self-awareness must be rethought human.

Research with wrasse fish

One of the studies that has revolutionized the field of self-awareness research in animals has been the research by Kohda et al. (2019) in which the behavior of a fish from the wrasse family was observed under the conditions of the mirror test.

The results of the study concluded that the fish reacted to its reflection when observed in the mirror and met all the criteria of the mirror test. However, when the fish was given a color tag in a modified brand test, the animal attempted to remove the mark scraping his body in the presence of the mirror, but showed no response towards transparent or colored marks in the absence of the mirror. mirror.

For the study authors, although the wrasse shows behavioral responses that meet the test criteria established for other animals, the result does not imply that this species is aware of itself. However, the results of this research open several questions that remain to be resolved: is this test really valid for detecting self-awareness in animals? And if so, if this species of fish is self-aware, should we rethink the concept?

Does the mirror test really measure self-awareness?

The validity of a test like the mirror test had not been seriously discussed until the publication of new investigations with species of animals that, a priori, we would never have thought are capable of showing signs of self-awareness. The positive evidence in fish and ants has forced a large part of the scientific community to raise doubts as to whether the mirror test is a good measure of self-awareness.

Alex Jordan, an evolutionary biologist and one of the authors of the controversial wrasse fish study, is reluctant to point out that fish are so intelligent such as chimpanzees or 20-month-old human babies, and questions the validity of the mirror test to measure the concept of self-awareness.

According to Jordan, one of the problems with the test is that vision is used to measure self-awareness. However, not all animals (or all humans) depend on sight as the predominant sense. For example, bats, which depend on their sonar to move, may be self-aware ourselves and we are simply not able, as humans, to formulate a test that detects it due to our bias visual.

Similarly, although elephants can pass the mirror test, they rely more on smell than sight, and the sophistication of their consciousness may have led to misinterpretations. In this sense, this test may simply not be suitable for some animals, because we do not have the same sensory view of the world.

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The "olfactory" mirror test

To overcome the visual bias of the self-awareness mirror test, Horowitz et al. (2017) designed an olfactory test for dogs that involved altering the smell of their urine. It should be noted that these animals have not passed the traditional test, since they are not able to recognize themselves in the mirror.

In the experiment, the researchers presented the dogs with various containers. Each of them with an olfactory stimulus: in one, the dog's own urine; and in the other, a urine whose smell had been altered. By observing how long each dog stayed in the containers, it was found that they were able to distinguish between the olfactory "image" of themselves and the modified one, tracking his own scent longer when it had an additional scent accompanying it, than when it did not.

The ecological validity of the olfactory test was examined by presenting the subjects with smells of other dogs. known or unknown: dogs spent more time investigating the scent of other canids than their scent own self. Finally, in a second experiment, the dogs spent more time with the modified stimulus than with the odor modified by itself, indicating that the novelty alone did not explain its behavior.

Ultimately, the results of this research suggest that the behavior of dogs implies a certain recognition of their own scent, which translated into the traditional self-awareness mirror test implies the existence of visual self-recognition or “self-awareness” in these animals. Something that should not surprise all those people who live with these domestic creatures.

Bibliographic references:

• Bard, K. A., Todd, B. K., Bernier, C., Love, J., & Leavens, D. TO. (2006). Self ‐ awareness in human and chimpanzee infants: What is measured and what is meant by the mark and mirror test?. Infancy, 9 (2), pp. 191 - 219.
• Horowitz, A. (2017). Smelling themselves: Dogs investigate their own odours longer when modified in an “olfactory mirror” test. Behavioral processes, 143, pp. 17 - 24.
• Kohda, M., Hotta, T., Takeyama, T., Awata, S., Tanaka, H., Asai, J. Y., & Jordan, A. L. (2019). If a fish can pass the mark test, what are the implications for consciousness and self-awareness testing in animals?. PLoS biology, 17 (2), e3000021.