Patrick Radden Keefe, writing in the New Yorker
Prosopagnosics often have strange stories about how they cope with their condition. The subjects had their own curious tales about being on the other end of the spectrum. They not only recognized character actors in movies—they recognized the extras, too. In social situations, prosopagnosics often smiled blandly and behaved as if they had previously encountered everyone they met, rather than risk offending acquaintances. Russell’s subjects described the opposite adaptation: they often pretended that they were meeting for the first time people whom they knew they’d met before. After all, if you’re introduced to someone at a party and you remind him, in pointillist detail, about the circumstances of a brief meeting years earlier, he might reasonably conclude that you are a stalker. One of the subjects described an ex-boyfriend’s referring to her as a “freak of nature.”
As someone who has a terrible time recognising faces — self-diagnosed prosopagnosia — I find this fascinating.
You can take the test that the Met puts its face recognition applicants through here.