From the Tartan Online, April 21, 2008

Cruising a familiar neighborhood, you probably expect greetings from the people you encounter on a regular basis – or you might be upset if someone you know passes you by. Still, before gaping at an offender’s rudeness, make yourself familiar with a severe recognition disorder that could be to blame.

Prosopagnosia, also known as face blindness, is a medical condition that prevents otherwise normal people from recognizing even commonly seen faces. While recent studies have suggested that the condition can be congenital – developed during the fetal stages of a person’s life – face blindness is usually a result of severe brain damage.

The region of the brain that houses the root of face blindness has yet to be discovered. However, scientists assert with some certainty that the target region is the cognition area, which helps humans learn about, remember, and recognize objects and people.

Major cases of face blindness may involve damage to the occipital and temporal lobes, which are responsible for visual perception and helping the brain acknowledge sounds, respectively.

Entire article here.