She has known my face since she was born, and I sort of feel like she knew it even before.
But how did she know to look for my face?
There is an area on the right side of the brain called the Fusiform Face Area. It’s thought to be specialized to tell the difference between human faces.
My mother could tell you every detail about my face, but can’t keep a dog and a cat separate, let alone two dogs. And before you get started, animals vary in looks a lot as well. Here’s an image of paper wasp faces; they recognize each other by the different patterns. However, the human brain is tuned to recognize faces. Even babies show a preference for faces.
There have been studies conducted in the field of developmental neuropsychology which show that babies will be able to tell the difference between animal faces as infants. This ability slowly fades over time as we get accustomed to looking at other human faces.
Of course you can, with practice, learn to tell the difference between things that at first look very similar. But we seem to have a built-in advantage in recognizing human faces.
If this area of the brain is damaged, or did not develop correctly, it can result in Prosopagnosia, also known as face-blindness. For these people, looking at people’s faces would be just like looking at different rocks, or animals. They would need to look at a very distinctive feature, like a certain hairstyle, or voice, to tell people apart.