Prosopagnosia

 There are a couple of things I'm thinking of these days and one of them is Prosopagnosia (or face blindness).

Oliver's book 

It's all about people not recognising  faces and there are some big names who've suffered it, they include Oliver Sacks (who wrote a book about it)  Stephen Fry, Comedian Paul Foot and seemingly the rather strange  connection of US photo-realist artist  Chuck Close.

I don't know if there are connections between sufferers (drug use?) or if it is more common amongst men or women but I can't help thinking that it tells us something about the human brain's operation.

Let's face it with several billion people in the world most with fairly 'standard' facial features it can seem pretty amazing that we can spot individuals visually - domestic animals often have keener senses of smells that humans but most of us are at least not conscious of detecting people by smell.

I recall about 25 years back on being required to meet a friend at HK Airport after not seeing him for some time anticipating spotting him being a challenge, it proved not to be the case but I do think about this and the point of losing this ability to differentiate as the years go by.