Mirror, mirror on the wall, who’s the fairest of them all?
—“Schneewittchen” (Snow White) / Grimms’ Fairy Tales, 1812
People are deeply fascinated by mirrors. The mirror is fundamental to life, science, and magic. It is a metaphor for many things, including mystery, vanity, infinity, symmetry, and enlightenment. Consider the Greek myth of Narcissus, who falls in love with his own reflection. When he realizes that the image is nothing but a reflection of himself, and recognizes himself in the image, he dies of lovesickness, fulfilling the prophecy made by the blind prophet Tiresias.
In developmental psychology, self-recognition and self-awareness are important milestones. Children usually reach them between 18 and 24 months of age. Around this time, they begin to show signs of self-directed behavior when looking at themselves in the mirror. For example, if they notice a mark, such as a red spot, on their forehead, they will try to remove it.