Incognito (21 page)

Let’s pause for a moment to consider how the team-of-rivals framework offers a different way of thinking about the brain than is traditionally taught. Many people tend to assume that the brain will be divisible into neatly labeled regions that encode, say, faces, houses, colors, bodies, tool use, religious fervor, and so on. This was the hope of the early-nineteenth-century science of
phrenology, in which bumps on the skull were assumed to represent something about the size of the underlying areas. The idea was that each spot in the brain could be assigned a label on the map.

But biology rarely, if ever, pans out that way. The team-of-rivals framework presents a model of a brain that possesses multiple ways of representing the same stimulus. This view rings the death knell for the early hopes that each part of the brain serves an easily labeled function.

Note that the phrenological impulse has crept back into the picture because of our newfound power to visualize the brain with neuroimaging. Both scientists and laypeople can find themselves seduced into the easy trap of wanting to assign each function of the brain to a specific location. Perhaps because of pressure for simple sound bites, a steady stream of reports in the media (and even in the scientific literature) has created the false impression that the brain area for such-and-such has just been discovered. Such reports feed popular expectation and hope for easy labeling, but the true situation is much more interesting: the continuous networks of neural circuitry accomplish their functions using multiple, independently discovered strategies. The brain lends itself well to the complexity of the world, but poorly to clear-cut cartography.

In the campy cult movie
Evil Dead 2
, the protagonist’s right hand takes on a mind of its own and tries to kill him. The scene degenerates into a rendition of what you might find on a sixth-grade playground: the hero uses his left hand to hold back his right hand, which is trying to attack his face. Eventually he cuts off the hand with a chain saw and traps the still-moving hand under an upside-down garbage can. He stacks books on top of the can to pin it down, and the careful observer can see that the topmost book is Hemingway’s
A Farewell to Arms
.

As preposterous as this plotline may seem, there is, in fact, a disorder called
alien hand syndrome
. While it’s not as dramatic as the
Evil Dead
version, the idea is roughly the same. In alien hand syndrome, which can result from the split-brain surgeries we discussed a few pages ago, the two hands express conflicting desires. A patient’s “alien” hand might pick up a cookie to put it in his mouth, while the normally behaving hand will grab it at the wrist to stop it. A struggle ensues. Or one hand will pick up a newspaper, and the other will slap it back down. Or one hand will zip up a jacket, and the other will unzip it. Some patients with alien hand syndrome have found that yelling “Stop!” will cause the other hemisphere (and the alien hand) to back down. But besides that little modicum of control, the hand is running on its own inaccessible programs, and that is why it’s branded as alien—because the conscious part of the patient seems to have no predictive power over it; it does not feel as though it’s part of the patient’s personality at all. A patient in this situation often says, “I swear I’m not doing this.” Which revisits one of the main points of this book: who is the
I
? His own brain is doing it, not anyone else’s. It’s simply that he doesn’t have conscious access to those programs.

What does alien hand syndrome tell us? It unmasks the fact that we harbor mechanical, “alien” subroutines to which we have no access and of which we have no acquaintance. Almost all of our
actions—from producing speech to picking up a mug of coffee—are run by alien subroutines, also known as
zombie systems. (I use these terms interchangeably:
zombie
emphasizes the lack of conscious access, while
alien
emphasizes the foreignness of the programs.)
³⁷
Some alien subroutines are instinctual, while some are learned; all of the highly automated algorithms that we saw in
Chapter 3
(serving the tennis ball, sexing the chicks) become inaccessible zombie programs when they are burned down into the circuitry. When a professional baseball player connects his bat with a pitch that is traveling too fast for his conscious mind to track, he is leveraging a well-honed alien subroutine.

Alien hand syndrome also tells us that under normal circumstances, all the automated programs are tightly controlled such that only one behavioral output can happen at a time. The alien hand highlights the normally seamless way in which the brain keeps a lid on its internal conflicts. It requires only a little structural damage to uncover what is happening beneath. In other words, keeping the union of subsystems together is not something the brain does without effort—instead, it is an active process. It is only when factions begin to secede from the union that the alienness of the parts becomes obvious.

A good illustration of conflicting routines is found in the Stroop test, a task that could hardly have simpler instructions: name the color of the
ink
in which a word is printed. Let’s say I present the word JUSTICE written in blue letters. You say, “Blue.” Now I show you PRINTER written in yellow. “Yellow.” Couldn’t be easier. But the trick comes when I present a word that is itself the name of a color. I present the word BLUE in the color green. Now the reaction is not so easy. You might blurt out, “Blue!”, or you might stop yourself and sputter out, “Green!” Either way, you have a much slower reaction time—and this belies the conflict going on under the hood. This
Stroop interference
unmasks the clash between the strong, involuntary and automatic impulse to read the word and the unusual, deliberate, and effortful task demand to state the color of the print.
³⁸

Remember the implicit association task from
Chapter 3
, the one that seeks to tease out unconscious racism? It pivots on the slower-than-normal reaction time when you’re asked to link something you dislike with a positive word (such as
happiness
). Just as with the Stroop task, there’s an underlying conflict between deeply embedded systems.

Not only do we run alien subroutines; we also justify them. We have ways of retrospectively telling stories about our actions as though the actions were always our idea. As an example at the beginning of the book, I mentioned that thoughts come to us and we take credit for them (“I just had a great idea!”), even though our brains have been chewing on a given problem for a long time and eventually served up the final product. We are constantly fabricating and telling stories about the alien processes running under the hood.

To bring this sort of fabrication to light, we need only look at another experiment with
split-brain patients. As we saw earlier, the right and left halves are similar to each other but not identical. In humans, the left hemisphere (which contains most of the capacity to speak language) can speak about what it is feeling, whereas the mute right hemisphere can communicate its thoughts only by commanding the left hand to point, reach, or write. And this fact opens the door to an experiment regarding the
retrospective fabrication of stories. In 1978, researchers
Michael Gazzaniga and
Joseph LeDoux flashed a picture of a chicken claw to the left hemisphere of a split-brain patient and a picture of a snowy winter scene to his right hemisphere. The patient was then asked to point at cards that represented what he had just seen. His right hand pointed to a card with a chicken, and his left hand pointed to a card with a snow shovel. The experimenters asked him why he was pointing to the shovel. Recall that his left
hemisphere (the one with the capacity for language), had information only about a chicken, and nothing else. But the left hemisphere, without missing a beat, fabricated a story: “Oh, that’s simple. The chicken claw goes with the chicken, and you need a shovel to clean out the chicken shed.” When one part of the brain makes a choice, other parts can quickly invent a story to explain why. If you show the command “Walk” to the right hemisphere (the one without language), the patient will get up and start walking. If you stop him and ask why he’s leaving, his left hemisphere, cooking up an answer, will say something like “I was going to get a drink of water.”

The chicken/shovel experiment led Gazzaniga and LeDoux to conclude that the left hemisphere acts as an “interpreter,” watching the actions and behaviors of the body and assigning a coherent narrative to these events. And the left hemisphere works this way even in normal, intact brains. Hidden programs drive actions, and the left hemisphere makes justifications. This idea of retrospective storytelling suggests that we come to know our own attitudes and emotions, at least partially, by inferring them from observations of our own behavior.
³⁹
As Gazzaniga put it, “These findings all suggest that the interpretive mechanism of the left hemisphere is always hard at work, seeking the meaning of events. It is constantly looking for order and reason, even when there is none—which leads it continually to make mistakes.”
⁴⁰

This fabrication is not limited to split-brain patients. Your brain, as well, interprets your body’s actions and builds a story around them. Psychologists have found that if you hold a pencil between your teeth while you read something, you’ll think the material is funnier; that’s because the interpretation is influenced by the smile on your face. If you sit up straight instead of slouching, you’ll feel happier. The brain assumes that if the mouth and spine are doing that, it must be because of cheerfulness.

On December 31, 1974, Supreme Court
Justice William O. Douglas was debilitated by a stroke that paralyzed his left side and confined him to a wheelchair. But Justice Douglas demanded to be checked out of the hospital on the grounds that he was fine. He declared that reports of his paralysis were “a myth.” When reporters expressed skepticism, he publicly invited them to join him for a hike, a move interpreted as absurd. He even claimed to be kicking football field goals with his paralyzed side. As a result of this apparently delusional behavior, Douglas was dismissed from his bench on the Supreme Court.

What Douglas experienced is called
anosognosia
. This term describes a total lack of awareness about an impairment, and a typical example is a patient who completely denies their very obvious paralysis. It’s not that Justice Douglas was
lying
—his brain actually believed that he could move just fine. These fabrications illustrate the lengths to which the brain will go to put together a coherent narrative. When asked to place both hands on an imaginary steering wheel, a partially paralyzed and anosognosic patient will put one hand up, but not the other. When asked if both hands are on the wheel, he will say yes. When the patient is asked to clap his hands, he may move only a single hand. If asked, “Did you clap?”, he’ll say yes. If you point out that you didn’t hear any sound and ask him to do it again, he might not do it at all; when asked why, he’ll say he “doesn’t feel like it.” Similarly, as mentioned in
Chapter 2
, one can lose vision and claim to still be able to see just fine, even while being unable to navigate a room without crashing into the furniture. Excuses are made about poor balance, rearranged chairs, and so on—all the while denying the blindness. The point about anosognosia is that the patients are not lying, and are motivated neither by mischievousness nor by embarrassment; instead, their brains are fabricating explanations that provide a coherent narrative about what is going on with their damaged bodies.

But shouldn’t the contradicting evidence alert these people to a problem? After all, the patient wants to move his hand, but it is not moving. He wants to clap, but he hears no sound. It turns
out that alerting the system to contradictions relies critically on particular brain regions—and one in particular, called the anterior cingulate cortex. Because of these conflict-monitoring regions, incompatible ideas will result in one side or another winning out: a story will be constructed that either makes them compatible or ignores one side of the debate. In special circumstances of brain damage, this arbitration system can be damaged—and then conflict can cause no trouble to the conscious mind. This situation is illustrated by a woman I’ll call Mrs. G., who had suffered quite a bit of damage to her brain tissue from a recent stroke. At the time I met her, she was recovering in the hospital with her husband by her bedside, and seemed generally in good health and spirits. My colleague Dr.
Karthik Sarma had noticed the night before that when he asked her to close her eyes, she would close only one and not the other. So he and I went to examine this more carefully.

When I asked her to close her eyes, she said “Okay,” and closed one eye, as in a permanent wink.

“Are your eyes closed?” I asked.

“Yes,” she said.

“Both eyes?”

“Yes.”

I held up three fingers. “How many fingers am I holding up, Mrs. G.?”

“Three,” she said.

“And your eyes are closed?”

“Yes.”

In a nonchallenging way I said, “Then how did you know how many fingers I was holding up?”

An interesting silence followed. If brain activity were audible, this is when we would have heard different regions of her brain battling it out. Political parties that wanted to believe her eyes were closed were locked in a filibuster with parties that wanted the logic to work out:
Don’t you see that we can’t have our eyes closed
and
be able to see out there?
Often these battles are quickly won by the party with the most reasonable position, but this does
not always happen with anosognosia. The patient will say nothing and will conclude nothing—not because she is embarrassed, but because she is simply locked up on the issue. Both parties fatigue to the point of attrition, and the original issue being fought over is finally dumped. The patient will conclude nothing about the situation. It is amazing and disconcerting to witness.