Over the decades, scientists have held up a literal mirror to various animals to determine if their minds have some sort of representation of the self.
elephantsmonkeys, dolphinsmagpies and clean wrasse are just a few of the menageries that join humans and chimpanzees in this exclusive club, and each responds to their reflection in a way that shows understanding that it represents themselves.
Scientists have now subjected Adelie penguins to a mirror test and have come up with mixed results. While it would be premature to conclude that penguins have a sense of self-awareness, the research team thinks there’s enough evidence to make this plausible.
Developed by Gordon Gallup in the 1970s, the mirror test has become a classic experiment for detecting self-awareness in animals. The method is relatively simple. Animals are first accustomed to a mirror in order to get used to its presence and reflectivity. When the subject is sedated, a clear mark is placed somewhere on their body where they cannot see it directly. When a confident animal sees the mark in the mirror, it will act in a manner that is aware that its body is marked and not some other individual.
As intuitive as it may seem, assuming responses to a reflection in different circumstances might indicate some sort of distinction in the self, The test is not without its limitations. Yet it remains one of the few means by which we can begin to examine the mind of another mind.
In a preliminary study awaiting peer review, a team led by Prabir Ghosh Dastidar of India’s Ministry of Geosciences introduced wild Adélie penguins (Pygoscelis Adeliae) to their own reflections during a series of experiments.
Penguins are very social animals, with Antarctic species relying on colonial groups to survive the cold extremes of winter. These animals are also relatively easy to test in the wild, unlike many other mirror tests that required animals to be kept in captivity.
A flock of 12 penguins were exposed to the mirror under different conditions. When exposed as a group, there was little response, but when isolated by cardboard cases and exposed to the mirror individually, the animals examined their reflections.
“The penguins made rapid movements of their heads, fins, or their bodies, some of which looked like gestures,” the team writes in their paper. “Many of these movements and gestures were quickly repeated, but what was striking was that all penguins’ visual attention was fixed on their images throughout the span of their performance.”
The birds did not attempt to make contact with or show aggression towards their reflection, suggesting that perhaps on some level they ‘knew’ that the bird in the mirror was neither friend nor foe, leaving only themselves behind.
However, when “tagged” with a red bib, the penguins didn’t respond to the change in appearance.
The team admits that there’s anecdotal evidence that not all penguins can even see red, so they’re not convinced by that result.
“Such experiments should be better designed in the future,” Dastidar and colleagues suggest, nevertheless, “our research leads us to tentatively suggest that Adelie penguins may be self-aware, as indicated by their reactions to their own images in a mirror.”
Since its introduction about half a century ago, there has been increasing evidence that the mirror test is not as clear-cut as suggested. Many animals known to be highly social fail the test, including monkeys, unless they are first trained to use a mirror.
Animals that we’re fairly confident are self-aware didn’t make it either, including gorillas.
Take dogs for example. They are capable of empathy, a trait that also implies a feeling for themselves and others, but they usually pass the mirror test.
“I believed that because dogs are much less sensitive to visual stimuli compared to humans and many monkeys, it is likely that the failure of these and other species in the mirror test is primarily due to the sensory modality chosen by the investigator to enhance self-awareness.” to test, and not necessarily for the absence of the latter,” explained evolutionary biologist Roberto Cazzolla Gatti of Tomsk State University in 2015.
Gatti tested this using a sniff test, which is equivalent to the mirror test for dogs. The dogs were tested to see how they reacted to displaced snow marked with their own or other dogs’ urine. In fact, the dogs spent much more time smelling the other dogs’ urine samples.
“This test provides significant evidence of self-awareness in dogs and may play a crucial role in showing that this ability is not just a specific trait of apes, humans and some other animals, but depends on the way researchers do it.” try to check it out,” Gatti said.
Other tests have since validated the idea that dogs have a clear sense of self, although it may not be visually based.
Furthermore, even our own children cannot pass the mirror test, with some not passing until the age of six in some countries. So while the mirror test might be able to indicate the presence of some self-awareness, failure does not seem to confirm the absence of this trait so important to sociality.
The original creator of the mirror test is skeptical about the penguin results so far.
“Penguins may actually be able to recognize themselves,” Gallup said New scientist. “But it would require much more serious science than what is contained in this paper.”
Given the complexity, it may be that self-awareness, like many other traits, is more of a spectrum than a dichotomy, as the mirror test implies. That would mean that we need new experiments to study this aspect of consciousness.
This research can be read via bioRxiv and is awaiting peer review.