Split brain and unified Self: how the subconscious protects us from ourselves

The driver, carried away by his thoughts, does not remember how he got to the place, does not remember how he decided to stop at a red light or turn on the turn signal. He’s on autopilot. Imagine a situation where a driver, having almost had an accident, suddenly wakes up from his reverie and slams on the brakes. The car screeches to a stop a few centimeters from the mail van. Calming down a bit, the driver considers what happened. He doesn’t feel like he was distracted for just a second. It seems that everything is much more serious. He gets the feeling that his consciousness did not take any part in the driving process. Lost in his own thoughts, it was as if he had gone blind.

These feelings are confirmed by scientific research. During one of the experiments, the subjects were put behind a car simulator and a headset was put on them. They had to drive a car and talk on the phone at the same time. The simulator was equipped with a three-dimensional map of a small city with sleeping, office and business districts (more than 80 blocks). There were many billboards with large and expressive inscriptions along the city roads. After practicing a little in driving a virtual car, the subjects set off on a journey along pre-designated routes, observing all road rules. During the ride, they talked on the phone using a headset. Next, the subjects passed a test: it was necessary to mark which of the billboards they encountered on the way. Their answers were compared with the answers of those participants in the experiment who traveled the same route, but without a phone. It’s not hard to guess that the participants, whose attention was occupied talking on their cell phones, performed worse on the test than those who were completely focused on driving. And although the billboards were in the most prominent places, the subjects who were talking on the phone simply did not notice them.

How could this happen? Didn’t the participants look at the billboards? To find the answer, the scientists put eye trackers on the subjects. With the help of these devices, it was found out that even when they were carried away talking on their cell phones, drivers did not stop actively noticing everything that appeared on the way. Their gaze shifted and focused on all important objects, including road signs, other cars, and even billboards. Strange. Drivers with headsets see the same objects as drivers without phones, but they can’t remember what they saw. How can this be explained? The theory is that the subjects’ eyes do look at objects, but the drivers are so engrossed in communication that they are not fully aware of what they have seen.

But if such large and noticeable road objects as billboards can be skipped because of some conversation, why is the number of accidents not increasing? After all, people are constantly talking behind the wheel, either with passengers or on the phone. How do we manage to drive and talk at the same time if talking affects our ability to see? Obviously, it is necessary to be aware of what you have seen in order to keep the distance between cars, drive in your lane, turn, and generally perform all those actions that allow you to get home without destroying your own car along the way. Nevertheless, experiments show that although our gaze switches from one road object to another, we often do not think about what we see.

But if conscious visual perception is disabled, then what controls our gaze? The brain takes care of this subconsciously. The subconscious mind initiates eye movements necessary to monitor cars, road signs and protect the driver and passengers from damage. That’s why there aren’t more accidents. That’s why busy drivers get to their destination unscathed. Although what we see is not fully realized, the brain’s subconscious processes take control of the visual system and lead us to our destination. This example shows how the connection between consciousness and vision is disrupted. The visual system works because the car does not get out of control, but the driver does not realize that he sees objects.

Certain neurological abnormalities confirm the fact that visual fixation and comprehension of what is seen are different processes. […]

What if when we try to perform several actions at the same time, such as talking on the phone and driving a car, it’s not both systems that get to work, but just one system that distributes its efforts between the two tasks? In this scenario, our success depends on how much attention we pay to each of the actions. The more attention, the better it turns out. But this scheme is not applicable to the operation of the habit system. If an action is brought to automatism, in most cases it is better not to pay significant attention to it.

On February 10, 2011, basketball player Ray Allen, then a member of the Boston Celtics team, made his 2561st accurate three-point shot, breaking the record set by Reggie Miller before him. All those years that Allen was in the NBA, he was famous for his attitude to work. Ray often came to the stadium about three hours before the start of the game to practice. In an interview, Allen was asked how he managed to achieve such success and what happens in his head when he throws the ball. The basketball player replied: “As soon as you start aiming, you will definitely miss. Do not forget about this during the game. You need to find a point on the field from which you no longer need to aim — just jump up and send the ball straight into the basket with a precise movement of your hands.”

For Ray Allen, throwing has become a habit. Perhaps this is what athletes mean when they talk about muscle memory. The method by which Allen focuses on an important throw is to not focus on it. If he thinks too much about how to throw the ball, he misses. He plays best when he instructs the habit system to do everything he has trained in.

The same applies to other athletes. In an experiment involving talented golfers, the subjects hit the ball twice. In the first case, they deliberately focused on the mechanics of the stick’s movement, carefully monitored the force with which they hit the ball, and carefully aimed. In the second case, the golfers didn’t think about hitting at all. As soon as they stood up with a stick in front of the ball, they were distracted by another task: they were asked to listen to recordings of sounds and wait for a certain signal, identify it and report it. The scientists then compared the results. As a rule, the ball was closer to the hole in cases when the players were not thinking about hitting. Golfers, like Ray Allen, played better if they didn’t think about what they were doing.

The revealed dependence of athletes’ success on whether they are guided by habit or consciousness confirms the idea that there are two parallel systems in the brain that control behavior. By repeating the same action, we can bring it to automatism, and then the habit system will take over. Our consciousness will be freed and, with the help of the unaccustomed system, will be able to concentrate on something else.

The division of labor between the two brain systems is not limited to just basketball or golf. The most subtle nuances of behavior can be regulated by habit or lack of it, and sometimes the difference is very noticeable. […]

There is one operation shown to people suffering from severe, uncontrollable seizures of epilepsy. It is called a callosotomy and is a dissection of the corpus callosum, a bundle of nerve fibers connecting the right and left parts of the brain. Since seizures are, in fact, electrical storms that sweep through the nerve bundles of the brain, the separation of its parts from each other prevents electricity from spreading and covering both hemispheres. This procedure is an extreme measure that helps a patient with uncontrollable seizures, but it leads to strange side effects.

The most famous and unpleasant of them is split brain syndrome. Ask Vickie, who had this operation in 1979. For many months after the surgery, the two parts of her brain operated independently of each other. For example, in the supermarket, she noticed that when she reached for a product with her right hand, her left hand acted completely on its own. “I reached out with my right [hand] for what I needed, but my left hand intervened and they started fighting. Almost like magnets with opposite poles,” says Vikki.

The same thing happened every morning. Vicky was picking up a set of clothes for herself, but one of her hands suddenly grabbed a completely unnecessary thing. “I had to dump all my clothes on the bed, exhale and get back to work,” she says. One day, Vikki got so tired of all this that she didn’t resist and left the house in three sets of clothes at once.

Split brain syndrome is a condition in which the divided hemispheres of the brain begin to act independently. Vickie suffered from alien hand syndrome. This syndrome is, among other things, directly related to split brain syndrome, since the right side of the brain controls the left arm, and the left side controls the right. This cross-control also applies to vision: the right side of the brain processes information about what is on the left side of the visual field, and vice versa. Moreover, the left side of the brain (in right-handers) controls speech. Each part of the split brain has its own unique set of capabilities that cannot be transferred to another part. For example, if Vickie uses her left hemisphere to read a word located on the right side of her visual field, she can say it out loud, because the left side of her brain controls spoken language. But when the same word appears on the left side of the visual field, where only the right hemisphere notices it, Vicky cannot pronounce it, but she can take a pen and write it down.

Neurologist Michael Gadzaniga, a leading specialist in the field of split brain research, has been working on this issue for five decades. In the course of his work, while discovering different and unique functions in the hemispheres, Gadzaniga wondered if each hemisphere had a separate self-perception. Both halves of the brain have access to their own sets of sensations and skills, but does each part have its own consciousness capable of thinking and making decisions?

In the 1960s, when Gadzaniga started his research, he thought there was. In the end, that’s exactly the conclusion that Vickie’s story about the supermarket leads to. However, he later became convinced that the two parts of the brain still make up a single “I”. Despite the lack of access to what the other hemisphere knows and does, the two halves of the brain work together to ensure the integrity of the personality.

In one experiment, Gadzaniga showed a split-brain patient the word “walk” by placing the word in the left side of the visual field, so that the word was perceived by the right hemisphere. The patient got up and walked. When asked why he did this, he explained, “I wanted to go get a coke.” The left side of the brain, responsible for speech, came up with this explanation because it did not know anything about the fact that the patient saw the word “walk.” Only the right side was aware of this. And the left hemisphere just came up with an argument.

Here is another example. Gadzaniga showed the right side of the patient’s brain an image of apples. The woman laughed when she saw him. When asked what the reason for the laughter was, she replied, “It seems that the device was very funny,” referring to the device showing the picture. When Gadzaniga showed the same image of the left side of her brain, she laughed again and quickly pointed to the image of a naked woman hidden among the apples.

Finally, in one of his favorite experiments, Gadzaniga showed the word “smile” to the right hemisphere of a split—brain patient and the word “face” to the left hemisphere. Then he asked the patient to draw what he saw. The patient made a smiling face. When Gadzaniga asked why, the patient replied, “Do you want a sad face? Who wants to look at sad faces?” The left side of the brain did not see the word “smile,” so the subject had to come up with an explanation for why the face was smiling.

In all these cases, the left side of the brain (responsible for speech) had no idea what the right side was seeing, but it was talented at inventing logical explanations for walking, laughing, and smiling on the painted face. Faced with conflicting information, the brain began to fill in the voids. If both parts of the brain are separate independent units, why should they cooperate in this way? Why not justify ignorance?

Even after surgical separation, the halves of the brain do not become completely independent units. They find a way to preserve the unity of our “I”. Gadzaniga reduces this phenomenon to the efforts of the left hemisphere, since in his experiments it was this part of the brain that invented all the arguments. He formulated the hypothesis that there is a “left-hemisphere interpreter” in the left side of the brain that tries to piece together everything that happens to us from day to day and construct a coherent and logical narrative. Gadzaniga acknowledges the results of a huge number of studies we have mentioned, confirming that our “I” is formed in the right hemisphere, but states that self-perception is provided by the entire brain — and the left hemisphere plays a crucial role here. It links fragments of our experiences into personal stories, guided by what we call neurology. At least in experiments involving split-brain patients, it is the left hemisphere that fills in the gaps.

Whether a left-hemisphere interpreter actually exists and how it functions remains to be seen. Nevertheless, we can already say with certainty that the subconscious system works in the brain, which, when faced with contradictory information, comes up with arguments to reconcile them. The subconscious mind acts this way in somatoagnosis and Capgras syndrome. It causes Cotard’s syndrome and makes up stories about alien visitors. It makes schizophrenics believe that they are being watched by FBI agents or that they are being controlled by supernatural forces. It becomes a source of confabulation and false memories. It invents our dreams.

The brain has a tendency to fill in the voids in our thoughts and feelings when they turn out to be incomplete. Every time the brain closes a gap, it does so with a specific purpose: to preserve our sense of self. The subconscious mind is entirely focused on protecting our personal history and the stability of our human identity.

Source: Theory and Practice