A Note About Prosopagnosia
There are two different types of face blindness, or prosopagnosia.
The type that Sadie has in this story is called acquired. It results from some sort of damage to the fusiform face gyrus—from surgery, for example, or a lesion, or a traumatic brain injury—and it results in a change in the ability to perceive faces.
The other type of prosopagnosia is developmental, and it’s typically a condition people have had all their lives. It’s more commonly associated with memory than with perception. People with developmental prosopagnosia can generally see faces in the moment—they just have trouble remembering them later. This type is by far the most common—up to one in fifty people have it—but many people don’t realize they have it. Because there’s no noticeable shift from before to after, many people who have this type assume that’s just how everyone is.
If you’re interested in learning more about face blindness, a good place to start is FaceBlind.org, a joint website of the Prosopagnosia Research Center of Dartmouth, Harvard, and the University of London. There you can read more about it, access online tests to measure your own ability to perceive and remember faces, and even volunteer to participate in research.