I came across this idea of seeing but not actually seeing whilst I was spending some time on the net and I think it's absolutely fascinating. The more technical term is PROSPAGNOSIA. Once you've got the hang of pronouncing that correctly, I shall continue.

Basically, it's when you have an impairment that doesn't allow you to recognise faces. Being forgetful after seeing someone, several years down the line isn't what I'm talking about.

Research was carried out and it was found that people with this condition can see the eyes, the nose, and the mouth, what is known as the context - but they cannot see a person as a whole. They do not recognise gestures nor emotions.