The human face is a versatile tool, but one of its most valuable qualities is that we are able to tell them apart. This ability is one of many things we rely on in our daily lives, but what if we couldn't tell the difference between faces? What if we couldn't identify our friends in a crowd of strangers? What if we ended up confusing our loved ones for household objects? This describes the unfortunate reality of individuals suffering from prosopagnosia.
Prosopagnosia is a neurological condition marked by an inability to recognize the faces of familiar people. Typically it's seen as being unable to recognize the face of someone you have met before. It could also be viewed, in some cases, as have trouble discriminating between unknown people's faces. Individuals with prosopagnosia might not even be able to recognize their own face and, at an advanced stage, it becomes difficult to discern between people and objects!
The word prosopagnosia comes from the Greek terms for "face" and "lack of knowledge." The condition itself isn't actually tied to memory dysfunction, memory loss, or even impaired vision, rather it seems to be the result of abnormalities in the brain structure, specifically in a region known as the right fusiform gyrus, which is a fold in the brain that is linked to facial perception. These abnormalities can be caused by traumatic brain injury, stroke, or neurodegenerative disease. In certain cases, it may even be congenital. Congenital prosopagnosia occurs in the absence of any brain damage and seems to run in families, suggesting a genetic component is involved with this variant of the condition. Prosopagnosia is even present, to a degree, in children with autism or Asperger's syndrome, a feature which may be a contributing factor to their impaired social development.
There are different ways to identify when an individual has prosopagnosia. A common feature of people with face blindness (another term for prosopagnosia) is an over-reliance on non-facial information, such as hair, clothing, or voice, along with other non-facial indicators. Another feature of prosopagnosia, which seems to be consistent in many cases, is the complaint of being unable to follow along with the plots of TV shows and movies, since they can't keep track of the identities of the characters. Individuals with prosopagnosia may also have trouble imagining the faces of people whom they have met or are familiar with.
Before the 2000s, most cases of prosopagnosia that had been documented were ones that resulted from brain damage. This is known as acquired prosopagnosia, and it is very apparent to suffer from it, as they have experienced normal facial recognition in the past and can easily notice their condition as a change. Meanwhile, cases of congenital prosopagnosia are much more difficult to identify, as individuals with this form of the condition would have lived all their life believing that everyone was like them. Since they're unaware of any deficits in their facial recognition, their cases often go unreported.
There are several estimates that suggest over 1 in 50 people suffer from prosopagnosia. Unsurprisingly, prosopagnosia tends create a lot of social problems for the person affected. You may have heard of the story of the man who mistook his wife for a hat, a neurological case which was documented by British neurologist Oliver Sacks. Prosopagnosia can be socially crippling for its subjects. Individuals can have trouble recognizing close friends or family, making many factors of social interaction difficult for the affected person.
The focus of treatment for prosopagnosia is to develop ways of recognizing people outside of facial identification. This includes using external clues from individuals' posture, attire, or even hairstyle. Ultimately, the best way to overcome prosopagnosia is through training in compensatory strategies of recognizing familiar people. This requires friends and family members to be conscious of the individual's condition and to be aware of what they can do to actively help them, especially in social settings or gatherings.