My neice Morgan and her husband Luke acquainted me with the neurological concept of Agnosia. As they explained it, this is the inability to attend to specific sensory data but has nothing to do with impairment of sensory organs. For example, a woman with agnosia might make up one side of her face looking in a mirror and leave the other side perfectly untouched, even though she had no difficuly actually seeing the both sides of her face clearly. A man might clean the food only from the right side of his plate, not taking a bite from the left side although all of it was perfectly tasty and he had no difficulty perceiving it.
Morgan and Luke have added a new wrinkle with something they term Distress Agnosia (Freud might have called this repression.) in which people are unable to respond to data that is simply too distressing to think about. The man who never notices that while he and his wife have black hair, his eldest son's hair is red; the folks who never stop to wonder why the neighbor kid gets a new puppy every week; the residents of Buchenwald who never speculate where all those trains are heading or why they suddenly have to spend so much time wiping oily soot off the windows and dining table. Who knows what horrible instances of Distress Agnosia we ourselves may have been prey to - by definition, we would be incapable of knowing. To have seen, perhaps, Satan Incarnate roaring like a lion in the subway, devouring screaming passengers right and left in his slavering maw, but our attention wandering to the more interesting seeming advertisements for community colleges pasted along the walls.
To Distress Agnosia I would like to add Distress Hypergnosia: the inability to stop thinking about things that distress us. Also, Dysgnosia, the irresistable impulse to think about the wrong things -- recalling for example an especially hilarious joke during a close friend's funeral, or suddenly recognizing in the license plate of the careening logging truck bearing down on you, an anagram of your own initials.
It all gets pretty tangled. Maybe I should think about something else.