How do we react to a person who is blind, but does not know it? Or a person whose arm is paralyzed, but denies it, even denies that the arm is his? They seem bizarre.
Someone may lose vision, movement, or speech, or even a large measure of intelligence, and we still count them as a person. But if their capacity for selfreflection is disabled, they seem to be much more profoundly damaged. It is not just because we are accustomed to mechanical devices and cameras that ordinary paralysis or blindness seems like "merely" mechanical damage. The reason is that although a function is missing, what is left to such patients is still well integrated. In contrast, disorders of self-monitoring seem to violate the defining entiticity of the person. It is this that makes them seem bizarre, somehow not quite human. Self-monitoring is one of the integrating processes that binds our separate parts.
This class of symptoms is called anosognosia, and in one form or another it is not uncommon following brain injury. Some particular brain lesions produce behavioral deficits in which the failure of self-monitoring is as striking as the failure of the primary performance. Most well-known are the left hemineglect often associated with right parietal lesions, the social inappropriateness associated with frontal lesions, and the confabulation associated with Korsakoff s syndrome.
A person's world is as much personal as external. Our experience is framed in relation to ourselves as subjects (perceivers, knowers) and as agents (actors, doers). Our most fundamental orienting is given by our monitoring of how we stand with respect to our goals. Many neurological injuries interfere with orientation in the "objective"
world, but it is more damaging to a person's integration to be out of touch with the dimensions of "personal" reality through loss of self-monitoring than to be out of touch with the externals through sensory loss or paralysis.
Anosognosias are important for psychologists, neurologists, and philosophers. These clinical phenomena offer hints and constraints for any theory of awareness and cognition. An enormously stimulating and useful book, Awareness ofDe$cit after Brain Znjuv, has recently been presented by Prigatano and Schacter (Eds.). It includes descriptions of the syndromes that follow different kinds of brain damage, models of underlying cognitive and neuropsychological mechanisms, and Discussion on Anosognosia: Unawareness of Severe Brain Damage.