Do you sometimes see your dog barking at itself in the mirror and wonder, “is he okay?”. Does he understand that he is seeing his own reflection? Does he understand that he is a “he”, an animal, a being with a brain?
One of the most extraordinary capabilities that humans have is the ability to recognize themselves in a mirror. This is remarkable because there is only a handful of animals capable of doing so in the entire world. Being able to recognize your reflection in the mirror means that you have self-awareness, which is the ability to see yourself and reflect on yourself. In other words, to be self-aware means to think about your behavior and realize that, for example, you are feeling angry because you are hungry, or that your TikTok watching habits are detrimental to your school performance. It also means that you’re able to think about yourself in the past (like childhood memories) and future (what will I do when I graduate?) and understand that you are and will be the same particular human entity at any point in time.
How does awareness take place in the first place? Although it has been difficult to pinpoint where exactly in the brain consciousness arises, studies using fMRI (Functional Magnetic Resonance Imaging) techniques have shown that activity in the medial frontal lobe, temporal lobe, and hippocampus is associated with self-awareness . Specifically, self-awareness is associated with medial frontopolar-retrosplenial areas, and both perceptual awareness and unaware self-processing are associated with activity in the inferior temporal cortex. I know, that is a lot of jargon, but the important thing is that these findings demonstrate that self-awareness has a neural basis, and that the extent to which an organism is self-aware or not is determined by the capabilities of its brain. However, mere activation of those brain regions does not always correlate with awareness, so how can we truly know if humans (or other animals) are self-aware?
The answer was given by George Gallup Jr., an American psychologist that studied biopsychology. He developed a test that would (in theory) prove if an animal was self-aware or not: the mirror test. This test consists of placing a marking, like paint or a sticker, on an animal’s face without them being aware of it (this is normally done under anesthesia) . Then, a mirror is presented to the animal, and if it reaches for its own face and investigates the abnormal mark, it is an indication that the animal is able to recognize itself and have visual self-awareness.
When are humans able to pass the mirror test? How old do you have to be to recognize yourself in the mirror? To answer that question, we first need to understand the 5 stages of awareness according to developmental psychologist Philippe Rochat . First, we have Level 0, Confusion, where there is absolutely no awareness and an individual doesn’t even understand what a mirror is. A bird that flies into a mirror and crashes is at this level, where it thinks that the mirror is an extension of the outside world. Level 1 is Differentiation, when an individual starts to perceive a mirror’s reflection as something that is not part of their environment, and realizes that there is something unique about the experience of looking at a mirror. They have the basic understanding that what they’re seeing is different, but they can’t really understand why yet. Level 2 is Situation, where the individual starts to realize that there is a correlation between the movements they feel themselves performing and the movements they see reflected in a mirror. In this level, there is no doubt in the individual that what they are seeing is unique to their experience, to their self. Level 3 is Identification, and as you might guess by its name, this is the level in which a human is able to pass the mirror test and recognize itself before a mirror. Identification occurs when a child is around 2 years old , and you can also notice this newfound identity in children when they start showing feelings of shyness, embarrassment, or seeking attention from others like their parents. The last two levels of awareness are Permanence and Meta awareness. The former refers to the ability to recognize yourself beyond the present experience, which means recognizing, for example, pictures of your younger self, pictures from before a haircut, or pictures where you are wearing different clothes than the ones you’re currently wearing. The latter refers to being able to recognize how other people perceive you; reflecting on what a teacher might think of you after you did poorly on a test is an example of Meta awareness.
As we saw, humans have enough self-awareness by the time they are 2 years old to recognize themselves in the mirror and are even able to develop more complex levels of awareness, but what about other animals? Are they able to pass the mirror test in the first place? It turns out that, yes! There are several animals that have passed the mirror test, and there are three instances where there was confirmed self-awareness in the species. The first animal that passed the mirror test was the chimpanzee. In 1970, Gallup (the same psychologist that designed the mirror test) showed that chimpanzees were self-aware when the macaques reached for their own faces in front of a mirror after seeing a red marking that had been placed while they were under anesthesia . Our second self-aware animal is the bottlenose dolphin, which in experiments done by psychologists Reiss and Marino have shown increased engagement with a mirror whenever markings were placed on several parts of its body . Finally, we have the Asian elephant, which interestingly is only able to show mirror recognition after it has inspected the mirror and played with its reflection, whereas chimpanzees and dolphins seem to make more of an immediate connection. Nevertheless, when elephants are marked with white “X”s on their face, they will inspect it with their trunks when they are presented with a mirror .
The former were examples in which, due to the experimental setups, it was clear that an animal was able to recognize itself in the mirror. However, “passing” the mirror test is not always enough proof that an animal is self-conscious. For example, psychologist Roger Thompson showed that you can train a pigeon to peck at marks on themselves in a mirror, but that in reality, the pigeon doesn’t recognize itself; it pecks only because it knows it will receive a reward ). Similar results from experiments with other animals (mainly birds) may give a false illusion that self-awareness can be “taught”, but in reality there has never been any documented cases of “induced” consciousness. Being self-aware has more complexity to it than simply responding to marks on a reflective surface, so careful assessment must be made before claiming that an animal is self-conscious.
So what makes us, chimpanzees, dolphins, and elephants special? Why are we able to pass the mirror test while other animals can’t? At the end of the day, we all have the same brain regions we mentioned earlier, right? In reality, we don’t really have an answer to this question yet, but it might have to do with the fact that human and primate brains are proportionately bigger than bird brains. However, this doesn’t explain self-awareness in elephants because they’re brain-body proportion is much lower than ours. More research is needed in order to understand the neural mechanisms that underlie these differences between organisms. In the meantime, I hope that what I told you today lets you appreciate how wonderful and privileged the human experience is because it allows us to experience self-awareness, and that next time you look in the mirror, you smile because you’re able to tell who is smiling right back at you.
 Gallup, G. G., Jr., Anderson, J. R., & Shillito, D. J. (2002). The mirror test. In M. Bekoff, C. Allen, & G. M. Burghardt (Eds.), The cognitive animal: Empirical and theoretical perspectives on animal cognition (pp. 325–333). MIT Press