A student came to the desk with a coworker to ask me a question. I answered him, and he continued his chat with the coworker. Suddenly, it ocurred to me that the student might *be* one of my coworkers. I looked and listened carefully, trying to observe his clothes to see if they were like what I remember him wearing. That and his hair matched, and his voice sounded pretty close. Ok, that must be my coworker.

Why didn't I recognize him? I'm pretty sure its because he wasn't wearing the glasses he usually wears. I still don't feel 'emotionally' sure it was him, but logically it's the only explanation.

But I've been told, both by a neurologist in their professional capacity and by a friend-of-a-friend with neurological experience and knowledge, though he doesn't know me very well, that I'm not faceblind.

Ok; what's the other explanation?