Friday, May 6, 2011

Prosopagnosia, the science behind face blindness : The New Yorker

I've just finished reading Chapter four from Oliver Sacks' latest book, The Mind's Eye. It is his first person account of being prosopagnosic. Definitely worth a read, since it has a lot of good background information on the condition itself.

Here is the Abstract for the article he published in the New Yorker as a lead-in media piece. The great thing about it when it came out was the number of readers, in New York and elsewhere, who became familiar with PA.

Prosopagnosia, the science behind face blindness : The New Yorker: "ABSTRACT: A NEUROLOGIST’S NOTEBOOK about prosopagnosia, or the inability to recognize faces and places. Writer describes his own difficulties recognizing and remembering faces. He also has the same difficulty with places and often becomes lost when he strays from familiar routes. At the age of seventy-seven, despite a lifetime of trying to compensate, he has no less trouble with faces and places than when he was younger. He is particularly thrown when seeing a person out of context, even if he was with that person five minutes before. Writer gives several examples of his inability to recognize familiar people out of context, including his therapist and his assistant. After learning that his brother suffered from the same problem, the writer came to believe that they both had a specific trait, a so-called prosopagnosia, probably with a distinctive genetic basis. Mentions several other people who have the same trait, including Jane Goodall and the artist Chuck Close. Face recognition is crucially important for humans, and the vast majority of us are able to identify thousands of faces individually, or to easily pick out familiar faces in a crowd. People with prosopagnosia need to be resourceful, inventive in finding strategies for circumventing their deficits: recognizing people by an unusual nose or beard, or by their spectacles, or a certain type of clothing. Describes research done on the way the brain recognizes faces. Tells about the work of Christopher Pallis, Charles Gross, Olivier Pascalis, Isabel Gauthier, and other scientists. Above all, the recognition of faces depends not only on the ability to parse the visual aspects of the face—its particular features and their over-all configuration—and compare them with others, but also on the ability to summon the memories, experiences, and feelings associated with that face. The recognition of specific places or faces goes with a particular feeling, a sense of association and meaning. Briefly discusses déjà vu and Capgras syndrome. Considers the difference between acquired prosopagnosia—through stroke or Alzheimer’s for example—and congenital prosopagnosia. Discusses the work of Ken Nakayama and Brad Duchaine, who have explored the neural basis of face and place recognition. They have also studied the psychological effects and social consequences of developmental prosopagnosia. Severe congenital prosopagnosia is estimated to affect two to two and a half per cent of the population—six to eight million people in the United States alone.

Oliver Sacks, A Neurologist’s Notebook, “Face-Blind,” The New Yorker, August 30, 2010, p. 36

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