We Think We make Decisions Logically. Do We? Decisions Actually Have
To Do with Interplay Between the Right and Left Hemispheres of Our Brain
The woman, for a fleeting moment, sees a picture of a nude, her face colors and she begins to chuckle with embarrassment. It is a beautiful California day. Can you guess exactly where she is? Strangely enough, she is a test subject—to preserve her personal privacy let’s call her Sue—in the highly respected psych testing facility at the California Institute of Technology, near Los Angeles.
Sue, in most every way, is just like you and me, with two exceptions. She has epilepsy, and has had her corpus callosum surgically severed―the large band of neural fibers that connect the right and left hemispheres of her brain―in a last resort attempt to cure her intractable epilepsy. She is a “split brain” patient. These patients provide, in my view, spectacular insights into the different functions of each half of our brains, and especially… how these two halves interact, or don’t, in daily moment-by-moment, real-time activity.
Finding Clues in the Lab
At Cal Tech with Sue is Dr. Roger Sperry, now renowned, and awarded a Nobel Prize in 1981, in part, for the groundbreaking research work he did with Sue, and other “split brain” patients like her during the 1960s. With their corpus callosum “disconnected,” all cross-talk and sharing of information between their right and left cerebral hemispheres ceases to exist for these patients. Originally, it was thought that performing such an operation―a callosotomy―would prove catastrophic for any post-surgery normal functioning as a human being. But Sperry’s work with cats and primates in the 1950s indicated otherwise.
In animal testing, Sperry found that disconnecting the hemispheres did not produce a catastrophic effect. In fact, all these animals, post-surgery, were able to live out surprisingly normal lives. The same was found to be true for the human split brain patients. Disconnection of the corpus callosum does not actually harm either hemisphere, nor does it damage any function in either hemisphere. The corpus callosum contributes no function of its own except that of a communication channel.
If you imagine two people talking on the telephone, and they suddenly lose the connection, neither person is harmed by the lost connection―the telephone line does not contribute anything to the actual conversation except its function as a physical channel for it. So, their conversation does come to an abrupt halt. They can no longer talk, share ideas with each other, perceptions, feelings, or any information whatsoever. The channel of communication is lost, but they just hang up the phone and go about their business, as normal.
In fact, if you were interacting with one of these patients, you would never know there was anything abnormal or different about their brain from your brain. But there are profound differences resulting from the disconnection, and only revealed by Sperry’s sophisticated testing. These patients presented a never-before-possible view of what each hemisphere is capable of… on its own, independent of the other!
As part of this group of about a dozen split brain patients studied in the 60s by Sperry, Sue is being tested on this beautiful day to study the effects of hemispheric “disconnection”―exploring what happens when each hemisphere is on its own. Sperry and his colleagues developed a clever method for sending verbal and visual information to just one hemisphere at a time. Using a special apparatus called a tachistoscope, a word or picture could be flashed to one hemisphere and not be seen by the other hemisphere. This “left brain not knowing what the right brain is doing,” or in Sue’s case, “seeing,” creates some very interesting results.
After a round of regular tachistoscope “picture and word” testing, Sperry, as a mischievous afterthought, shows a picture of a nude to Sue. Now, the tachistoscope only allows Sue’s right hemisphere to see it, and only for a fraction of a second, but long enough to provoke her right hemisphere into blushing with soft laughter. What happens next is absolutely amazing.
Function of the Corpus Callosum in the Normal BrainIn a normal, intact brain, the right and left hemisphere of the brain share massive amounts of information with each other through the 200+ million connecting fibers of the corpus callosum. In the example presented in the next paragraph, remember, due to cross-lateralization, activity occurring in the far left visual field is seen only by the right hemisphere. Activity occurring in the center area of the visual field, directly ahead when facing forward, is observed by both hemispheres simultaneously. And activity occurring in the far right visual field is observed only by the left hemisphere. If a potential threat, say a large dog, approaches you from the far left visual field, only your right hemisphere sees it directly. However, through the corpus callosum, your left hemisphere is immediately “informed” of the potential threat, and you instinctively turn your head to the left, so both your hemispheres can directly see the potential threat’s approach and consider a unified response while assessing the threat level. This is just one example of normal inter-hemispheric communication and integrating or synchronizing information to both hemispheres. For most tasks, the corpus callosum enables each hemisphere to be very “aware” of information possessed by the other hemisphere. But what happens when the hemispheres are not so “aware” of each other?
I first learned about Sue in the summer of 1993, nearly 30 years after the episode I describe above. Reading, for the first time, about Roger Sperry’s work with split brain patients on that warm July day changed everything about my understanding of human nature and what makes us tick.
Finding Clues in the Field
By that point in my career, five years on as an executive coach and corporate trainer, I and my colleagues had delivered scores of NLP-based sales training and personal influence programs to the likes of Sun Microsystems, Dupont, and other big name clients. These programs were done under the auspices of Malandro Communication, a training company based in Scottsdale, Arizona.
There were three fundamental principles we taught in those programs around which all of the learning exercises in the course were designed. The first one is the most interesting and relevant here: “People make decisions based on subjective experience, and later validate those decisions with logic.” You could roughly translate that to, “People make decisions based on how they feel, then, ‘feeling a little foolish,’ are compelled to look for or make up some seemingly rational reasons for their decision (for example, to tell their spouse).”
We as instructors, of course, were at one time ignorant of, and had to learn this principle for ourselves. Yet it was still always a wonder to us how so few of our participants knew they made decisions just below the level of their conscious awareness based on feelings—what looks good, sounds good, and especially what feels right.
Even after we provided several demonstrations that showed the phenomenon and the principle were true, there were always a few diehards—logical types—who still insisted they made decisions based on logic. So, with our assistance, after a “careful review” of several recent decisions each had made, even these diehards saw the light before the end of the first day.
If you don’t believe this yourself, consider: the field of applied psychology has used this principle to revolutionize the effectiveness of the marketing and advertising industries. Watch any of the current breed of television commercials and you will see the focus is on eliciting positive feelings from the viewer, with little to no reliance on or presentation of logical reasons a viewer might actually find useful in making a decision.
You could say that people are generally clueless they make decisions based upon feelings below the threshold of their conscious awareness. People are equally clueless their effort at logical validation of any decision occurs after the fact; and this validation is merely a formality and followup to the “fait accompli”—the fact the decision has already been made by their subconscious mind.
We are compelled to validate our decisions with logic by our need to believe and appear we have been logical and sensible. This compulsion is the result of a broad range of social and cultural influences we experience growing up. These influences condition us to believe we should—that it is superior to—base our decisions and actions on logic and not base them on feelings.
Over time, as a result of this conditioning, we gradually shut down the channels of communication from our subconscious to our conscious mind—channels so open and vibrant when we are young. We begin to ignore those communications typical of the subconscious mind that occur in the form of feelings, impulses, intuitions, and ideas. We downplay them, repress them, we “hang up” on them when we get a “call” from them. By degrees, an “estrangement” from a very important part of our “self” begins. I maintain that this self we become estranged from is our right hemisphere personality.
We found, during hundreds of exercises using a series of special questions designed to uncover deeper layers of subconscious desires, that most people, by the time they reach adulthood, have minimal conscious access to their subconscious minds. It is only when asked these probing questions do they get conscious access to deeper motivations.
Ironically, after one of these exercises, typically a participant would be both pleased and surprised at discovering the total picture of why, both consciously and subconsciously, they “really” wanted something (or didn’t). It was refreshing for them, even for a moment, to “discover themselves” at these multidimensional levels of consciousness—to be aware of the fullness of who they are.
On the other hand, each program often had one or a few participants who were already quite self-aware, and had a good grasp of this principle. They had effective personal strategies for uncovering subconscious desires and personal criteria, and bringing them to the level of their conscious awareness.
Perhaps most striking was the fact they were comfortable admitting that their subconscious desires often were not rational, and nonetheless, stood by them unapologetically—they were frank and ”truthful.” This “authenticity” was refreshing, and I often thought, and said to them, “You have a good partnership with your subconscious mind. Guard and cherish it.”
It also occurred to me that this authenticity with good judgment is a good marker for a well-integrated mind—a mind that equally values its conscious and subconscious aspects. During each program there was formal time for participants to critique each other. A frequent comment about these few, with noticeable admiration from their peers, was, “You really know yourself and know what you want.”
In those early days, I had no idea I would soon find out my experiences were profoundly linked with the very architecture of the brain.
Converging Clues from the Lab and the Field
On that July day, I’m spellbound as I read Sperry’s work. Sue, with blushing cheeks, is still chuckling as Sperry, with a smile on his face, asks her, “What are you laughing about?” By one account, with only a moment’s pause for thought, Sue says, “Why, Mr. Sperry, you have such a funny tie.”
That… was a eureka moment for me, one among many I had that day. But in that particular moment, I felt like I was right there, in the lab with Sperry and his colleagues and Sue. It was also like my brief, half decade of training experiences descended upon me and fell into place—a different “place” of understanding. I saw immediate parallels between Sue’s made-up response to Sperry’s question, and the equally made up rationalizations of normal people.
Sue, in the moment of thought before she responded, just made up an answer, she confabulated. She lied, albeit unwittingly. I was utterly amazed. I remember getting up and quickstepping around my house, book in hand, crying out loud several times, “Even people with a perfect corpus callosum make sh!+ up!” Now, I can forgive you if you don’t quite share my excitement, or understand my melodrama.
Remember, only the left hemisphere has the capability of speech. Sue was communicating with Sperry exclusively from her left hemisphere consciousness, just like Joe in the last article. Due to the disconnection of her hemispheres, Sue had absolutely no conscious awareness in her left hemisphere that her right hemisphere had just seen a picture of a nude. There was no callosal transfer of that information. She, with great innocence, just confabulated a plausible story based on what she knew—the fact she could feel her facial muscles creating a chuckle, minus any clue as to why—and chose the closest available possibility for such humor, Sperry’s tie.
But, fascinating as those facts are, what really amazed me was this: I realized, from my training experiences, that even people with perfectly intact brains also confabulate, make things up, “lie” (sometimes unwittingly, sometimes intentionally), or, to put it in the vernacular, “make up a load of bs” to explain decisions subconsciously made by their right hemisphere. And, even more amazingly, Sperry’s work exposed, as never before, the actual physical brain mechanism and brain structure by which this occurs—interplay (or the lack of) between the right and left hemisphere via the corpus callosum.
Now, in case you are thinking that Sue’s case is an anomaly—an isolated, singular case of confabulation—from which I should not draw such an expansive generalization, I would like to introduce you to Michael Gazzaniga. As a graduate student, he was there with Sperry during this initial testing of split brain patients. He, most notably, has carried on Sperry’s investigation of split brain phenomena to the current day, and has written numerous books on cognitive brain phenomena.
Gazzaniga, too, was fascinated by the implications of this confabulation behavior, of which Sue’s story is an example. He has continuously observed and confirmed this same behavior with many split brain patients, and has written extensively about it. Gazzaniga discovered these patients would readily and quickly make up a theory—even with very limited and incomplete information to go on—to account for and explain the little they did know.1,2,3,4,5
In Sue’s case, all she knew in her left hemisphere was physiological information from her facial muscles and sound from her own chuckling. She knew nothing of her right hemisphere’s experience of seeing a nude and finding self-conscious humor in it. When asked by Sperry why she was laughing, her left hemisphere quickly formed a “logical” theory based solely on her chuckling, and then linked it to Sperry’s tie. Her theory was, of course, wrong.
After replicating this behavior many times with other split brain patients, Gazzaniga proposed the existence of a device in the left brain he calls the “interpreter” to account for this theory-making. He has found it only exists in the left hemisphere, and that the interpreter regularly makes these errors. Further, this limited information, theory-making of the left hemisphere is not restricted to split brain patients. Everyone does it!
Consider this YouTube video segment, Severed Corpus Callosum, from the PBS series, Scientific American Frontiers where Gazzaniga demonstrates for host, Alan Alda…
I find uncanny parallels between Gazzaniga’s notion of theory-making on the part of the logical left hemisphere and my training experiences with the principle “people make decisions based on subjective experience, and then, after the fact, attempt to validate those decisions with (theory-making) logical reasons. Gazzaniga’s findings localize this theory-making function exclusively to the left, speaking hemisphere!
As intensely interesting as all that is, what Gazzaniga found the right hemisphere does is even more fascinating. The right hemisphere does not make up theories. In the same kind of testing, he discovered, in his word, right hemisphere responses are “veridical” and literal. In other words, the right hemisphere tells only the truth (veridical) and nothing but the truth (literal). It seems the right hemisphere would make a good courtroom witness, doesn’t it? Or, if you are familiar with science fiction writer, Robert Heinlein’s novel, Stranger in a Strange Land, the right hemisphere qualifies as an excellent “fair witness.” The right hemisphere is the epitome of honesty and authenticity!
The make-it-up left hemisphere squeezed into the same cranium with the truth-telling right hemisphere explains a lot about ordinary life. Consider a husband’s choices when his wife asks, “Do I look fat in these jeans?” What does he choose? Does he make up something? Or does he tell the truth? Or…are his left and right hemispheres integrated enough to manifest an “emergent property”—elegant authenticity?
Forgive me for suddenly dropping a new term on you, this idea of an emergent property. I will cover the concept of emergent properties in depth, as it relates to the two hemispheres of the brain, in a future article. For now, I’ll define an emergent property as a surprise result from integrating two simpler constituents. The surprise aspect can sometimes be seen to border on the amazing.
Elegant authenticity, in the example above, is not a trait or property of either hemisphere on its own, but is a result of a profound partnership between the two. I surely see a breakthrough opportunity when we come to understand our right and left hemispheres as each a human personality that are built to work together.
A Practical Application
To pull this all together, Sperry and Gazzaniga’s work with split brain patients revealed the existence of a device in the left hemisphere that Gazzaniga calls the “interpreter.” Everyone has an interpreter in their left hemisphere which stands ready to make up a theory and story to explain information it senses coming from the right hemisphere. The theory is often wrong. The right hemisphere, by contrast, does not make up theories. If it doesn’t have the information to answer a question, it will indicate it does not know. It reports the truth, as it knows it, literally, with no embellishment.
The right and left hemisphere in normal people carry on this same interplay. However, for them, information can pass back and forth to both hemispheres through the corpus callosum. Even so, left hemisphere theory-making is often wrong. Through my own experience with clients, their conscious awareness of subconscious motivators is meager, resulting in frequent errors by the left hemisphere interpreter, even though the corpus callosum is there to provide that awareness.
Errors can be transformed, however, by better integration of the two hemispheres. This can be done through effort driven by your personal commitment to developing self-awareness and learning self-inquiry techniques. In future articles I’ll present simple exercises to recapture the integration you had when you were young, and preserve the maturity you have now. All your communication will improve… with others, and most importantly, with yourself. Following is one practical application of the knowledge presented in this article.
Besides having a positive professional impact, this information also had a deep personal effect upon me. I thought this must certainly mean I, too, interpret my own behaviors and decisions, prone to frequent errors. With that realization, I decided to slow down my interpretations and check for deeper level motivations.
Nowhere was this more immediately beneficial and noticeable than in raising my two boys. As little boys do, they often asked for permission to do this or that. And my answer was frequently a “no.” When I began slowing down my interpretations and asking myself, ‘For what real purpose am I answering with a no? What is my real concern here?’ I discovered my deeper reasons were often baseless resting on trivialities, and I started saying ‘yes’ much more frequently.
I also began incorporating this “slowing down” and self examination in many contexts with good effect. I felt my authenticity was improving. I invite you to try it yourself.
With its rich language and speech capability, the left hemisphere is a full, conscious, self-aware human personality. Of that there has never been a doubt. Is the same true of the non-speaking right hemisphere has been the controversial question.
With Sue and other split brain patients, Sperry and Gazzaniga have shown the right hemisphere can do nearly everything the left hemisphere can do—some things not as well and some things better—except speak. The right hemisphere, as demonstrated by Sue and others, can experience humor (even of the somewhat ribald variety), and self-conscious embarrassment—unquestionably these are traits of human personality. But are they sufficient to prove “double consciousness”—that the right hemisphere is a second, independent and complete human personality?
In the next article, I will present evidence even more amazing from Sperry’s research that furthers the compelling case each hemisphere is a “mind of its own,” an individual, independent human personality with its own set of preferences, beliefs, behavioral strategies, and personal style of communication. You will discover, to use an analogy, whatever can happen between two brothers (or two sisters) can happen between the left and right personalities of the two brain hemispheres, including physical violence with each other!
For now, I would like you to consider some of what Sperry concluded from his research findings with split brain patients.
In Sperry’s own words from his 1977 lecture at the Smithsonian Institute:
Each hemisphere can be shown to experience its own private sensations, percepts, thoughts, and memories that are inaccessible in the other hemisphere. …In this respect, each surgically disconnected hemisphere appears to have a mind of its own, but each cut off from, and oblivious to, conscious events in the partner hemisphere.
Also from this same lecture: Consciousness, Personal Identity and the Divided Brain:
…we have not been able to see any real justification for denying consciousness to the disconnected mute [right] hemisphere. Everything we have observed… over many years of testing reinforces the conclusion that the mute hemisphere has an inner experience of much the same order as that of the speaking hemisphere, though differing in quality and cognitive faculties. Clearly, the right hemisphere perceives, thinks, learns, and remembers, all at a very human level. …Further, it can be shown to generate typical, human emotional responses.
For the first time, through the results of Sperry’s work with “divided” hemispheres and carried on by Gazzaniga and others, we get a clue that the right hemisphere just may be the “unconscious mind” Freud was speaking of when he first coined the term.6
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Copyright © 2011 by Mentor International Inc
All rights reserved
1 Michael S. Gazzaniga, Who’s in Charge? Free Will and the Science of the Brain,
Ch. 3, “The Interpreter” (New York: HarperCollins, 2011).
2 Michael S. Gazzaniga, Human: The Science Behind What Makes Us Unique, pp. 289-308 (New York: HarperCollins, 2008).
3 Michael S. Gazzaniga, The Ethical Brain, pp. 147-151 (New York: Dana Press, 2005).
4 Michael S. Gazzaniga, The Mind’s Past, pp. 130-148 (Berkeley and Los Angeles: University of California Press, 1998).
5 Michael S. Gazzaniga, Nature’s Mind: The Biological Roots of Thinking, Emotions, Sexuality, Language, and Intelligence, pp.121-137 (New York: BasicBooks, a division of HarperCollins, 1992)
PBS series, Scientific American Frontiers: “Severed Corpus Callosum”
Roger Sperry’s 1977 lecture at the Smithsonian Institute
6 S.P. Springer and G. Deutsch, “The Right Hemisphere and the Unconscious,” P.344, Left Brain, Right Brain: Perspectives from Cognitive Neuroscience, 5th Edition (New York: W.H. Freeman and Company, 1998)
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