A Scanner Darkly

�About that speech I gave�� Fred said.

�What this is about,� the left-hand medical deputy said, as he seated himself and produced a pen and some forms, �stems from a recent departmental survey showing that several undercover agents working in this area have been admitted to Neural Aphasia Clinics during the past month.�

�You�re conscious of the high factor of addictiveness of Substance D?� the other deputy said to Fred.

�Sure,� Fred said. �Of course I am.�

�We�re going to give you these tests now,� the seated deputy said, �in this order, starting with what we call the BG or��

�You think I�m an addict?� Fred said.

�Whether you are an addict or not isn�t a prime issue, since a blocking agent is expected from the Army Chemical Warfare Division sometime within the next five years.�

�These tests do not pertain to the addictive properties of Substance D but to�Well, let me give you this Set-Ground Test first, which determines your ability readily to distinguish set from ground. See this geometric diagram?� He laid a drawn-on card before Fred, on the table. �Within the apparently meaningless lines is a familiar object that we would all recognize. You are to tell me what the �

Item. In July 1969, Joseph E. Bogen published his revolutionary article �The Other Side of the Brain: An Appositional Mind.� In this article he quoted an obscure Dr. A. L. Wigan, who in 1844 wrote:

The mind is essentially dual, like the organs by which it is exercised. This idea has presented itself to me, and I have dwelt on it for more than a quarter of a century, without being able to find a single valid or even plausible objection. I believe myself then able to prove�(1) That each cerebrum is a distinct and perfect whole as an organ of thought. (2) That a separate and distinct process of thinking or ratiocination may be carried on in each cerebrum simultaneously.

In his article, Bogen concluded: �I believe [with Wigan] that each of us has two minds in one person. There is a host of detail to be marshaled in this case. But we must eventually confront directly the principal resistance to the Wigan view: that is, the subjective feeling possessed by each of us that we are One. This inner conviction of Oneness is a most cherished opinion of Western Man. ��

�� object is and point to it in the total field.�

I�m being Mutt-and-Jeffed, Fred thought. �What is all this?� he said, gazing at the deputy and not the diagram. �I�ll bet it�s the Lions Club speech,� he said. He was positive.

The seated deputy said, �In many of those taking Substance D, a split between the right hemisphere and the left hemisphere of the brain occurs. There is a loss of proper gestalting, which is a defect within both the percept and cognitive systems, although apparently the cognitive system continues to function normally. But what is now received from the percept system is contaminated by being split, so it too, therefore, fails gradually to function, progressively deterioriating. Have you located the familiar object in this line drawing? Can you find it for me?�

Fred said, �You�re not talking about heavy metals trace deposits in the neuronecepton sites, are you? Irreversible��

�No,� the standing deputy said. �This is not brain damage but a form of toxicity, brain toxicity. It�s a toxic brain psychosis affecting the percept system by splitting it. What you have before you, this BG test, measures the accuracy of your percept system to act as a unified whole. Can you see the form here? It should jump right out at you.�

�I see a Coke bottle,� Fred said.

�A soda pop bottle is correct,� the seated deputy said, and whipped the drawing away, replacing it with another.

�Have you noticed anything,� Fred said, �in studying my briefings and like that? Anything slushed?� It�s the speech, he thought. �What about the speech I gave?� he said. �Did I show bilateral dysfunction there? Is that why I�ve been hauled in here for these tests?� He had read about these split-brain tests, given by the department from time to time.

�No, this is routine,� the seated deputy said. �We realize, Officer Fred, that undercover agents must of necessity take drugs in the line of duty; those who�ve had to go into federal��

�Permanently?� Fred asked.

�Not many permanently. Again, this is percept contamination that could in the course of time rectify itself as��

�Murky,� Fred said. �It munks over everything.�

�Are you getting any cross-chatter?� one of the deputies asked him suddenly.

�What?� he said uncertainly.

�Between hemispheres. If there�s damage to the left hemisphere, where the linguistic skills are normally located, then sometimes the right hemisphere will fill in to the best of its ability.�

�I don�t know,� he said. �Not that I�m aware of.�

�Thoughts not your own. As if another person on mind were thinking. But different from the way you would think. Even foreign words that you don�t know. That it�s learned from peripheral perception sometime during your lifetime.�

�Nothing like that. I�d notice that.�

�You probably would. From people with left-hemisphere damage who�ve reported it, evidently it�s a pretty shattering experience.�

�Well, I guess I�d notice that.�

�It used to be believed the right hemisphere had no linguistic faculties at all, but that was before so many people had screwed up their left hemispheres with drugs and gave it�the right�a chance to come on. To fill the vacuum.�

�I�ll certainly keep my eyes open for that,� Fred said, and heard the mere mechanical quality of his voice, like that of a dutiful child in school. Agreeing to obey whatever dull order was imposed on him by those in authority. Those taller than he was, and in a position to impose their strength and will on him, whether it was reasonable on not.

Just agree, he thought. And do what you�re told.

�What do you see in this second picture?�

�A sheep,� Fred said.

�Show me the sheep.� The seated deputy leaned forward and rotated the picture. �An impairment in set-background discrimination gets you into a heap of trouble�instead of perceiving no forms you perceive faulty forms.�

Like dog shit, Fred thought. Dog shit certainly would be considered a faulty form. By any standard. He �

The data indicate that the mute, minor hemisphere is specialized for Gestalt perception, being primarily a synthesist in dealing with information input. The speaking, major hemisphere, in contrast, seems to operate in a more logical, analytic, computerlike fashion and the findings suggest that a possible reason for cerebral lateralization in man is basic incompatibility of language functions on the one hand and synthetic perceptual functions on the other.

� felt ill and depressed, almost as much as he had during his Lions Club speech. �There�s no sheep there, is there?� he said. �But was I close?�

�This is not a Rorschach test,� the seated deputy said, �where a muddled blot can be interpreted many ways by many subjects. In this, one specific object, as such, has been delineated and one only. In this case it�s a dog.�

�A what?� Fred said.

�A dog.�

�How can you tell it�s a dog?� He saw no dog. �Show me.� The deputy �

This conclusion finds its experimental proof in the split-brain animal whose two hemispheres can be trained to perceive, consider, and act independently. In the human, where propositional thought is typically lateralized in one hemisphere, the other hemisphere evidently specializes in a different mode of thought, which may be called appositional. The rules or methods by which propositional thought is elaborated on �this� side of the brain (the side which speaks, reads, and writes) have been subjected to analyses of syntax, semantics, mathematical logic, etc. for many years. The rules by which appositional thought is elaborated on the other side of the brain will need study for many years to come.