PROSOPAGNOSIA, or face-blindness, affects 2.5% of the population. Those afflicted cannot recognise faces, even ones they have seen before and know well. They must learn to rely on other cues such as gait, spectacles and manner of dress.

Oliver Sacks, a neurologist and writer, is himself face-blind. He has also been living with ocular cancer. In his latest book, "The Mind's Eye", he considers six cases of people who have had to adjust to big changes in their vision, including himself. The stories, some previously published in the New Yorker, are heartbreaking: a writer who loses the ability to read, a pianist who can no longer read music, Dr Sacks's own face blindness and loss of stereo vision as a result of cancer. His stories humanise his subjects and give shape to conditions that seem otherwise impossible and unliveable. Yet these are hardly sob stories. Rather, Dr Sacks offers up many examples of the plasticity of the human brain, which can adapt to almost anything.

More Intelligent Life spoke to Dr Sacks over the phone about face-blindness, the line between biology and biography, and what it was like for him to become one of his own subjects.

When was the first time you realised you were face blind, and when did you start thinking of it as a real condition?



Probably the first time was in ‘85 when I visited my brother in Australia, whom I had had no personal contact with since the 1950s. He had difficulties recognising faces and places in the same way I have and we both had a sudden feeling that this was a family thing, though my other siblings don't have it. This was the first time I consciously thought that way. And then after my "hat" book ["The Man Who Mistook His Wife for a Hat"] was published, I received letters [about conditions] that were confined to faces. Neurologists started to wonder whether there was a congenital form which had been under-reported. It turns out face recognition is a pre-attentive process, and should be instant.



How often do you think this happens? That one has a condition and assumes that it's "a personality thing"? How many more conditions like this will come to light?



Lots of them. One doesn't tend to think of oneself of having a condition. Especially if others in the family have it, they attribute it to "the way we are". Once after giving a talk on tourettes in London I took a taxi and the cabdriver was a flamboyantly tourettic, cursing, jumping on the roof. And I asked him very shyly if he had tourettes, which he denied indignantly. It is not easy to recognise a condition until it is pointed out: dyslexia is one of them, and it affects 10% to 15% of the population.



What is the effect of something like face blindness on personality?



One can react and respond in all sorts of different ways to blindness. Some people will avoid embarrassment and confusion and all social contact. Others will become extremely attentive to matters of dress and movement and voice, so much so that they become tuned automatically to how people are dressed and how they move. For my part I think I'm good at recognising posture and movement. I'm a little bit on the reticent side—that's a primary characteristic of face blindness. People should perhaps "out" themselves. In the book I tell a story where a man goes to a physician and says he can't recognise people, and so his life has become "a round of apology and offence". The matter must be aired. If people know you're face blind you don't have to apologise.



You have written so many stories about the conditions of others. Was it different writing your own case history?



There are many different forms of writing. Sometimes I'm listening to myself as as if I were another subject, and sometimes I'm talking about the pain and fear inside of me. Many years ago someone said to me you tell case histories—why not do your own? And that's what I did. When did the idea for writing a book about face blindness first come to you? And how do you think your own experience propelled you?



The last piece in the book wasn't written till January of 2010, though I have correspondence on the subject for 20 years or so. I don't know how much this propelled me. There are two famous neurologists, Henry Head and Russell Brain (two very appropriate names for neurologists). Henry Head was very interested in sensation, but he felt he couldn't experiment on patients after they came in to be helped. So he asked a colleague to divide two nerves in his own forearm and then he kept a journal about his recovery. It is valuable to use oneself as a subject as long as one can be objective. With the cancer I'm sorry I have it but I might as well use it.



It seems you are very interested in the idea of humans being adaptable, and the way we get around limitations.



Very much so. This sort of theme goes right back to the beginning for me. Sometimes with neurological things the person's other powers must kick in.



glowing review of your book in the LA Times quotes the critic C.P. Snow's desire for a "third culture" to bridge the gap between science and the humanities, and argues that you bridge this gap.



I did like that. I always wanted to get people's stories and access to their lives. I feel I'm at the interface of biography and biology, person and person-hood. I remember one man with Tourettes, who wrote and said that he had 'a tourettised soul', it affects one and one affects it—there's a liaison of a sort. A condition is sometimes a collusion, and sometimes a compromise. Although it's up to me as a neurologist to diagnose the disease and to think in therapeutic terms, I always want to address the person as much as the disease, and I'm very glad my own doctor feels similarly. I'm not just a case to him, I'm a person responding to the situation. So I somehow sit between the biology and the humanist point of view.



You write about conditions that are familiar but also very foreign, which many people have not experienced. Can one ever really know the experience of someone else through description?



I sort of sit in the middle here. I think I quite like Bertrand Russell's distinction of knowledge by description and knowledge by acquaintance—like me in "Stereo Sue"—no description could match what's happening to me now. But one must try as hard as possible to be precise and eloquent. I think concrete examples of what it's like are very telling. So when Sue describes what snowflakes are like or the steering-wheel of a car, one understands.



Yes, I particularly liked her poetic descriptions of the objects she came to see again.



May I now ask you a question? Did "Stereo Sue" make think about your own vision?



Yes, actually. So much so that I sought out a "Magic Eye" book to test my own stereo vision.



I'm delighted you say that. I do feel it's all worth it if I can make one reader question how they see.



Can you speak a little bit about the connection between artists and visual conditions?



Yes, an interesting example of this is Chuck Close, who is severely face blind. So much so that as people move their head he loses them; they seem unfamiliar. But he's a genius with fixed, flat photographic images of faces—in this case a particular flaw is inverted to find a wonderful gift. Researchers at Harvard thave hypothesised based on his self portraits that Rembrandt's eyes were too divergent and that he couldn't have had binocular vision, and paradoxically they suggested this could have been an advantage. At the time I thought this was nonsense. That is, 'till I lost stereo vision, and found that the world looks more like a painting or a photograph or a cinema screen. I no longer see objects residing in 3-D space, but shapes juxtaposed with one another by sizes and colours: what one needs to see if one needs to compose to give the illusion of three dimensions. I know artists who look through a tube to mimic this effect.



Have you thought about making art yourself?



I always used to have a stereo camera. My drawing is idiotic, such as the childlike diagrams in the book. I am moved to go back to photography, although I do think I would need to enter a digital world, which I'm reluctant to do.



What's your next professional project?

The next project will be a book on hallucinations, a subject which really needs a book to itself. It's a wonderfully rich subject and I've written quite a lot already.



"The Mind's Eye" by Oliver Sacks is published by Alfred A. Knopf in America, Picador in Britain, and is out now

Picture Credit: Columbia University