Alexa Tsoulis-Reay, from Science of Us, talks with someone with profound Prosopagnosia:
Say I showed you a bowl of fruit for 20 seconds. You would remember it as a bowl of fruit. If I let some time pass and asked you to tell me where the apple, pears, and bananas were positioned, you probably wouldn’t be able to. You would have to stare at that bowl of fruit, and commit it to memory, and you would have to know that you had to commit it to memory when you were looking at it.
To tell people apart I have to find a distinguishing feature. And context is huge. If I’m expecting to see somebody, I’ll figure out who they are by observing their body language, listening to their voice. Good-looking people are the most difficult to recognize.
This person’s description really paints a picture. When a key component to getting by in society goes missing, one has to rely on brute force methods, like memory and visual association, just to build an approximation of recognition.