Everyone is guilty of forgetting the name of someone they've met before, although people are generally quite good at remembering faces, and especially at recognizing close friends and family at a glance. For some people, recognizing faces is an impossibility due the neurological disorder known as prosopagnosia (also called face blindness. For them, loved ones can appear to be strangers. People with prosopagnosia cannot recognize familiar faces and often cannot distinguish among the faces of strangers. They may also have trouble recognizing familiar places or objects or seeing the difference between someone's face and another object. Some people with prosopagnosia even have difficulty recognizing themselves. Researchers estimate that one in 50 people may have some form of prosopagnosia.
Developmental prosopagnosia appears during childhood and may have genetic roots or be due to a prenatal or childhood brain abnormality or damage. Children on the autism spectrum often display some degree of prosopagnosia, which may account for their social limitations. Acquired prosopagnosia can occur in older men and women after a brain injury, stroke, or the onset of degenerative disease.