You may want to think before setting a mousetrap; Because the mouse can also think.
A new study has found that mice seem to recognize themselves in a mirror, placing them in a rare category alongside humans, primates, dolphins and the smartest birds.
According to research published Tuesday in Neuron, black lab mice painted with white paint and placed in front of a mirror will work diligently to remove the paint; This is an early indication that they recognize that the mouse in the mirror is them.
Researchers tend to be very wary of any findings that seem to convey animal sentience, and in this case, researchers from the University of Texas Southwestern Medical School were hesitant to conclude that the mice were self-aware.
They noted that it was possible for mice to detect a change in their appearance without a basic conscious experience that connects them to humans, elephants, or magpies.
For this reason, researchers were careful to use phrases like “self-recognition-like behavior” rather than drawing broader conclusions about the inner experiences of their little test subjects.
However, the finding that the mice interacted with the mirror creature as themselves, rather than as a friend or rival, opens the door to the possibility that the mice are more self-aware than generally thought.
The mirror test emerged half a century ago through animal consciousness research that began with our closest relatives, chimpanzees.
Zoologist George Gallup Jr. He painted the chimpanzees’ faces with odorless red paint and placed them in front of a mirror to see if they would interact with the spot.
When they did so, the findings became a powerful argument that animals, often viewed in mid-century scientific dogma as biological machines with no inner life, have a consciousness similar to ours.
In some cases, this capacity exceeded that of humans: Children could often walk and talk before passing the mirror test.
Over the past half-century, a wide variety of other animals have also passed the test: great apes in the 1970s, followed by bottlenose dolphins in the 1990s, elephants and magpies in the late 2000s, and zebrafish in 2019.
Although passing the mirror test is linked to consciousness, failing does not necessarily mean a lack of consciousness. This is largely because the test is based on a vision of intelligence in a sensory world that privileges humans, where vision is the dominant sense, where touching our limbs is the primary way of interacting with and preparing for the world. important.
For example, cats failed the mirror test, but this may be due to the notorious lack of cooperation in laboratory settings or anything else rather than a cognitive failure. (As Science reports, cats tend to fail many intelligence tests that dogs pass because of their habit of wandering around in the middle of experiments.)
Cats’ failure to pass the test may also be due to the fact that, like dogs, they prioritize scent to distinguish themselves from others.
Tuesday’s findings also reinforce the role of social learning in letting animals know what a mirror is or what their face should look like. UT researchers found that black-furred mice passed the test; but only mice raised with other black-furred mice, not mice raised alone or among white mice.
This finding suggests that “mice must have social experiences with other similar-looking mice to develop the neural circuits necessary for self-recognition,” the researchers wrote in a statement.
In another important caveat, the mice appeared to pass the test only if they had previously spent time getting used to and grooming themselves in front of the mirrors.
They need some support, too, said Jun Yokose, lead author of the study.
“The mice needed significant external sensory cues to pass the mirror test; we need to put a lot of ink on their heads,” he said, adding that the visual stimulus of seeing it, as well as the feeling of ink on their fur, raises that possibility. The image reflected in the mirror was necessary for the mice to notice the stain.
“Chimpanzees and humans don’t need any of this extra sensory stimulation,” Yokose added.
These caveats are consistent with those observed in other species that pass the mirror test only when their unique size or sensory data are taken into account.
Elephants only got by with adequately large mirrors, and magpies, crow relatives that use their beaks instead of limbs to interact with the world, needed specially designed stickers they could remove with their mouths.
Primatologist Frans de Waal, who has conducted mirror tests on elephants, said such findings are likely just the beginning of research into animal consciousness.
Quoting physicist Wevern Heisenberg, de Waal wrote, “What we observe is not nature itself, but nature subjected to our method of inquiry.”
He noted that Heisenberg “made this observation in relation to quantum mechanics, but it is equally valid for animal research.”
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