Michael S. Gazzaniga Quotes

The psychology professor Richard Aslin once commented to me that he felt the idea of “consciousness” was a proxy for a whole host of variables correlated with our mental lives. We use “consciousness” as shorthand to easily describe the functions of a multitude of inborn, instinctual mechanisms such as language, perception, and emotion. It becomes evident that consciousness is best understood as a complex instinct as well. All of us come with a bucketful of instincts. Our incessant thought pattern jumps around. We have feelings about one idea, then its opposite, then our family, then an itch, then a favorite tune, then the upcoming meeting, then the grocery list, then the irritating colleague, then the Red Sox, then … It goes on and on until we learn, almost against our natural being, to have a linear thought.

enabled conscious experience itself — we humans enjoy mental states that arise from our underlying neuronal, cell-to-cell interactions. Mental states do not exist without those interactions. At the same time, they cannot be defined or understood by knowing only the cellular interactions. Mental states that emerge from our neural actions do constrain the very brain activity that gave rise to them. Mental states such as beliefs, thoughts, and desires all arise from brain activity and in turn can and do influence our decisions to act one way or another. Ultimately, these

A clearer picture of what is happening in the brain during non-REM sleep,14 during sleepwalking,15 and during confused arousals16 has been achieved through neuroimaging and EEG. It appears that the brain is half awake and half asleep: the cerebellum and brainstem are active, while the cerebrum and cerebral cortex have minimal activity. The pathways involved with control of complex motor behavior and emotion generation are buzzing, while those pathways projecting to the frontal lobe, involved in planning, attention, judgment, emotional face recognition, and emotional regulation are zoned out. Sleepwalkers don’t remember their escapades, nor can they be awakened by noise or shouts, because the parts of the cortex that contribute to sensory processing and the formation of new memories are snoozing, temporarily turned off, disconnected, and not contributing any input to the flow of consciousness.

It was only twenty-five years ago that the philosopher Joseph Levine officially dubbed it the explanatory gap, which he later described in his book Purple Haze: We have no idea, I contend, how a physical object could constitute a subject of experience, enjoying, not merely instantiating, states with all sorts of qualitative character. As I now look at my red diskette case, I’m having a visual experience that is reddish in character. Light of a particular composition is bouncing off the diskette case and stimulating my retina in a particular way. That retinal stimulation now causes further impulses down the optic nerve, eventually causing various neural events in the visual cortex. Where in all of this can we see the events that explain my having a reddish experience? There seems to be no discernible connection between the physical description and the mental one, and thus no explanation of the latter in terms of the former.2

There obviously is a different feel to a wave of intense emotion versus an abstract thought, but each conscious form is an experience that gives us a unique perception of reality. The pattern in which these various conscious forms come in and out of awareness gives us our own personal life story. The vast variety of conscious forms and the ubiquity of consciousness in the brain are best explained by a modular architecture of the brain. The conceptual challenge now is to understand how hundreds, if not thousands, of modules, embedded in a layered architecture — each layer of which can produce a form of consciousness — give us a single, unified life experience at any given moment that seems to flow flawlessly into the next across time.

I am not suggesting that single cells are conscious. I am suggesting that they may have some type of processing that is necessary or similar to the processing that results in conscious experience.

Split-brain patients act in a unique way. It appeared the left, speaking hemisphere initially offered a utilitarian response to all scenarios. Thus, if an act had mal-intent but no harm came from it, it was judged as “permissible.” And if an act did not have mal-intent, but resulted in harm, it was judged “forbidden.” Given the clarity of the stories used, this was a jarring result. What is going on? The disconnected left hemisphere is unable to take into account the intent of the person in the stories, acting as if it didn’t have a theory of mind.

As in any layered system, however, the system can become jeopardized if a core component that transfers information from one layer to another malfunctions. In the case of biological tissue, if the kinds of proteins that connect cells together are defective, then information may not be able to transfer from the individual-cell layer to the tissue layer, and the entire system could shut down. While not perfect, the layered design of biological systems is advantageous because it minimizes the number of points in the system that, if attacked, would result in catastrophic damage, and it limits the effects of attacks at other points.

This incessant interplay between cognition and feelings, which is to say between cortical and subcortical modules, produces what we call consciousness.

According to Panksepp, seven primal emotional and motivational feelings that appear to be common features of animal and human consciousness at both a behavioral and a neural level are SEEKING, FEAR, RAGE, LUST, CARE, GRIEF, and PLAY.

Adding to our understanding of why the brain seems undisturbed by disconnections was not only the notion that it was, in a sense, sending half its decisions into the realm of the unconscious; it was also the discovery of the “interpreter.” This special left brain system kept note of all the behaviors that resulted from the many mental systems. It appeared to be the surveillance camera on our behavior, which, of course, was the evidence that a mental or cognitive act had occurred. The interpreter not only took note; it tried to make “sense” out of the behavior by keeping a running narrative going on about why a string of behaviors was occurring. It is a precious device and most likely uniquely human. It is working in us all the time as we try to explain why we like something or have a particular opinion, or rationalize something we have done. It is the interpreter device that takes the inputs from the massively modularized and automatic brain of ours and creates order from chaos. It comes up with the “makes sense” explanation that leads us to believe in a certain form of essentialism, that is, that we are a unified conscious agent. Nice try, interpreter!

Symbols lead a double life, with two different complementary modes of description depending on the job they are doing. In one life, symbols are made of physical material (DNA is made of hydrogen, oxygen, carbon, nitrogen, and phosphate molecules) that follows Newton’s laws and constrains the building process by its physical structure.

Barbieri chides that “natural selection is the long-term result of molecular copying and would be the sole mechanism of evolution if copying were the sole basic mechanism of life.”15 But it isn’t. While genes can be their own template and copy themselves, proteins cannot. Proteins cannot be made by copying other proteins. The tricky thing is that only molecules that can copy can be inherited, so the information about how to make the proteins had to come from the genes. Barbieri notes that the outstanding feature of the very early protein makers “was the ability to ensure a specific correspondence between genes and proteins, because without it there would be no biological specificity, and without specificity there would be no heredity and no reproduction. Life, as we know it, simply would not exist without a specific correspondence between genes and proteins.”16

When communication between the hemispheres is lost, each is unaware of the other’s knowledge and each functions independently based on the information it receives. Both sides of the brain try to complete the task independently, resulting in the tug-of-war. By this simple task, the illusion of a unified consciousness is exposed. Clearly, if consciousness arose from a single location, then a split-brain patient would be unable to have two simultaneous experiences!

24 It is worthwhile to take a moment to understand the difference between a structural and a functional network. “Structure” refers simply to the physical anatomy of a network: how many neurons, how they are arranged, their shape, and so forth. A functional network performs a certain function; it may have to do with speaking language, or it may have to do with understanding language. Importantly, the structure of a network does not reveal its function, or vice versa.