Who's That Baby in the Mirror?
When babies recognize their own reflections, and what it means for development.
Posted Feb 10, 2020
Since the very first time my son looked in a mirror, he was in love with what he saw: A cute and chubby little baby beaming back at him. He turns his head back and forth and watches in delight as the baby in the mirror mimics his every move. He smiles and laughs and even tries to kiss himself. He never for a second seems to recognize that the baby in the mirror is simply his own reflection; instead, it is just another cute baby to play with.
Recognizing their own reflection isn’t something that babies can do until around 18 months of age. The first sign that babies recognize themselves in the mirror is from what researchers call the “rouge test.” The test involves putting a bit of lipstick (or rouge if you were wearing makeup when the test was invented in the 1970s) on a baby’s nose and then putting the baby in front of a mirror to observe his or her reaction. Before 18 months of age, babies show no signs of noticing the lipstick whatsoever; they smile at the baby in the mirror, just like my 8-month-old son does. Around a year and a half, their reactions start to look different. For the first time, the rouge-nosed babies look somewhat distressed and try to rub the lipstick off their own noses instead of playing with the cute baby in the mirror (Lewis, 1995).
It isn’t clear why it takes babies 18 months to recognize themselves. It doesn’t seem to matter how much experience they have looking in mirrors either; babies who have never seen a mirror before show the same pattern of responding when compared to babies who see mirrors all the time (Priel, and de Schonen, 1986). And we know that they recognize that their faces are familiar in both photographs and videos by 8 months of age, preferring to look at faces of a new baby than at their own face (Bahrick and Moss, 1996).
Recognizing themselves in the mirror seems to be a bit more complicated, and involves being able to think about themselves as independent beings that have minds and thoughts that are separate and distinct from yours or mine. This is important, as it marks the beginnings of theory of mind. Theory of mind is the understanding that other people have thoughts and feelings that are separate from yours. It is what allows children to understand other people’s intentions and emotions, and is related to a variety of important prosocial behaviors, like sharing and helping, and potentially even deceptive behaviors like lying.
Importantly, a sense of self is also related to the development of the self-conscious emotions like empathy, guilt, shame, embarrassment, and pride, which each require a child to compare their own actions to the expectations of others. For example, for a child to feel guilt, they have to understand that something they have done might have caused someone else to be upset or angry. Likewise, to feel pride, he needs to understand that something he has done might elicit admiration from others. These emotions aren’t generally observed in children until the second year of life after they’ve shown evidence of having a sense of self—after they’ve stopped trying to play with the baby in the mirror and have learned to recognize themselves in their reflections.
Mirror recognition (and the advanced cognitive and emotional abilities that come with it) isn’t an easy feat, and in fact, few animals can recognize their own reflections in a mirror. Besides humans, only the great apes, some monkeys, and dolphins seem to be able to do it. It might be part of what makes us uniquely human. And although 18 months sounds like an awfully long time to be clueless about the fact that you are that cute baby staring back at yourself, it means that by a year and a half, babies are already discovering that they have a unique place in the world, which sets the stage for the many new and exciting discoveries that are yet to come.
Bahrick, L. E., & Moss, L. (1996). Development of visual self-recognition in infancy. Ecological Psychology, 8(3), 189-208.
Lewis, M. (1995). Embarrassment: The emotion of self-exposure and evaluation. In J. P. Tangney & K. W. Fischer (Eds.), Self-conscious emotions: The psychology of shame, guilt, embarrassment, and pride (pp. 198-218). New York, NY, US: Guilford Press.
Priel, B., & de Schonen, S. (1986). Self-recognition: A study of a population without mirrors. Journal of experimental child psychology, 41(2), 237-250.