face it: prosopagnosia

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.

via The Economist.