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The Primal Urge to Know
and the Primal Urge to Relate
The human brain is puzzling, to say the least. By itself—separated from a body and a person—it appears unimpressive, though strange. Slightly larger than a melon, walnutlike in its wrinkles and grooves, putty or clay in appearance, its immediate features are evident (see figure 1.1).
The tissue that we see is the neocortex—evolutionarily the newest part of the brain. In humans it is so large that it must be intricately folded so as to fit within the skull. Viewed from the top, the neocortex is divided into two halves or hemispheres, left and right. Deep grooves, called sulci, divide each half into four sectors, or lobes. The paired frontal lobes lie behind the forehead and occupy most of the front half of the brain; they deal with intentionality and help coordinate the functions of the other cortical areas.
Behind the frontal lobes, across the top of the head, are the parietal lobes. These deal with general sensory information. On the sides of the head and behind the frontal lobes are the temporal lobes. These process sounds and, in humans, speech. The occipital lobes, in the back of the head, are the center for processing visual information. It should be noted that these specializations are not absolute; the various parts of the brain contribute to each of these complex functions.
Hidden under the wrinkled cap of the neocortex are other parts of the brain.If we were to flip our specimen brain upside down, the part on top would now be the brain stem. It connects the brain to the spinal cord and also is responsible for various functions critical to the maintainance of life, such as circulation, respiration, and temperature control. The brain stem also activates behaviors related to the basic survival of the individual and of the species: reflexes; movement patterns; fight, flight, or freeze responses to danger; and seeking a mate. Next to the stem is the bulbous cerebellum, the area that primarily coordinates motor activity. All vertebrates have brain sectors much like this one.
Sandwiched between the neocortex and the brain stem and hidden beneath the surface is a portion of the cortex evolutionarily older than the neocortex. Found not only in humans but in all mammals, it is primarily responsible for emotion, caretaking, and memory. This portion of the cortex, along with some parts of the brain stem that collaborate with it, is collectively referred to as the limbic system.
The inner part of the brain includes several commissures, or nerve-tissue bridges that carry information from one part of the brain to another. The most important of these is the corpus callosum, which connects the right and left cerebral hemispheres. Cells called glia provide support and nourishment to various parts of the brain but do not transmit information.
At birth, the human brain contains billions of nerve cells, or neurons, but they are largely unconnected with each other. Some connections, like those that enable a toddler to walk, develop on their own natural timetable; for example, even children who are blind learn to walk without ever observing anyone else doing so. Although much of a brain's basic architecture is genetic, the structure and connectivity of the brain are also molded to a very significant extent by each individual's experiences—by interaction with people and physical conditions in the environment.
Although most of the brain's neurons are present at birth, the brain multiplies in size and weight several times over as a child matures. This growth is due to the proliferation of axons and dendrites.
Axons are "branches" that carry messages out from a neuron; an axon may be several inches long. Dendrites are bushy structures to which axons from other neurons connect; dendrites are the receivers of messages. An axon comes into contact with a dendrite from another neuron at an area called a synapse (see figures 1.2 and 1.3).
Messages pass from axons to dendrites through activity mediated by chemicals called neurotransmitters.
Learning calls forth new axons and dendrites, and the brain's weight thus multiplies several times over during childhood. Throughout life, new connections form new networks of neurons; old networks may, in time, lose power from lack of use. Thus, learning is lifelong, and, in general, the more one continues to learn, the better the brain continues to function through the years.
In fact, it seems that people who are dissatisfied with parts of their mental organization—old "hangups"—can deliberately work to modify that neural organization through certain forms of psychotherapy. Various powerful experiences, including religious experiences, can be transformative. There is a striking parallel here with the early formation of neural networks. As we will see in chapter 4, to develop into a normally functioning human being, a small child must live amid interactions of love. Deprived of such interactions, a child will not develop normally. Similarly, the "remodeling" of neural networks also seems to require interaction with a loving "other." That "other" may be a therapist, a wise friend, someone mediating the presence of a loving God, or mystically experienced transcendence. To call forth deep, positive change requires the presence of deep wisdom and love.
While this description of features and functions is accurate, it oversimplifies both the complexity and the specificity of the human brain. This odd-appearing mass of matter turns out to be the most compelling, the most powerful, the most intriguing matter in the known universe. Nothing can match its majesty; nothing can approach its complexity; nothing can detract from its sophistication. It, and it alone, provides entrance to all that is human and humane, yes and all that is distorted and dysfunctional, in our known world.
In these two opening chapters we set forth our understanding of the humanizing brain and its humanizing activity. In doing so we intertwine brain evidence and God-talk.
We propose that the concept "mind" denotes the human meaning of the brain. The genetic brain shapes the developing mind. In turn, the developing mind reshapes the physical brain. The result is an emergent mosaic of meaning-seeking and meaning-making as to what matters to the survival and thriving of the human species. It is our brain-mind that marks our human grandeur and our all-too-pervasive misery.
Two features are basic to our brain and its working. They can be interpreted in either nonreligious or religious ways, because we humans live in two worlds—the everyday world of time and space and the extraordinary world of meaning and ultimate concern:
Our brains are "hardwired" to seek out and respond to the human face. This propensity keeps us humans oriented to what is human. It also makes us basically relational in our stance in the world.
We humans keeping trying to make sense of what we experience. As a result, we keep organizing the random and disorganized—both things and ideas. This propensity contributes to what matters to our survival—and to what is significant for who we are.
In short, our brain orients us to the basically human, to what is complex and whole. In technical language, these features mean we are object-seeking/ meaning-making creatures. Like Siamese twins, the seeking and the meaning processes intertwine. We separate them only for purposes of analysis and understanding.
The 1981 Nobel Prizes awarded in "physiology or medicine" dramatically symbolize the intersection between the physical environment and the world of meaning. One prize went to Roger W. Sperry for his work in identifying "some effects of disconnecting the cerebral hemispheres." This is known more popularly as "split-brain research." The other laurel went to David H. Hubel and Torsten N. Wiesel for their work on "the primary visual cortex and the influence of environment."
For us, a meeting between religion and neuroscience focuses on the issue of how we humans hold together sensory processing and symbolic processing. This connects perceptual realism and psychic meaningfulness. Sperry's work lifts up two streams of conscious organization; Hubel's and Wiesel's work identifies highly specific visual response patterns. Together these researchers provide clues to the way our brain humanizes what we encounter.
MAKING SENSE OF EXPERIENCE: THE PRIMAL URGE TO KNOW
Consider first Sperry's work on split-brain patients. Behind the discovery of two streams of consciousness lies a more basic capacity—specifically, the drive to make sense of what we experience. We regard this drive as the inquiring, meaning-seeking capacity of the human brain. The empirical evidence supports a human bias for order.
How do people put things together cognitively? To answer that we turn to a clinical study of a sixteen-year-old boy named Paul. The case illustrates the way we make sense of the world whether we are brain injured or have a normally functioning brain.
What Do You See and What Does It Mean?
Paul was one of about fifty patients operated on for uncontrollable epileptic seizures. The surgery consisted of opening the skull and cutting the main fiber tract that sends messages back and forth between the left and right hemispheres (see figure 1.4). That tract is called the corpus callosum. Different sections of it connect with different areas of the cortex. Researchers hoped this would stop the spread of the electrical thunderstorm flashing from one side of the brain to the other. In controlling the seizures, the operations proved successful. However, more subtle problems arose. We say more about this in chapter 6. Here we point to the way Paul handled the task of identifying objects.
Researchers asked him to sit at a table and look at a single point in the center of a blank screen directly in front of him (see figure 1.5). They flashed pictures of objects to either side of the fixation point. Then they asked him to identify what he saw. The speed of the flash allowed only the hemisphere to which the stimulus was directed to "see" what was on the screen. That is, the left hemisphere would see only what was in the right visual field and the right hemisphere only what was in the left visual field.
Almost our entire nervous system works in this crossover way. The left brain controls the right side of the body, and the right brain controls the left side of the body. This is true of what we take in as well as what we put out. Since the connecting fiber tract of the corpus callosum had been cut, neither hemisphere knew what the other hemisphere knew.
To the right of the fixation point the researchers flashed a chicken claw. Therefore, Paul's left hemisphere received the picture. To the left of the point they flashed a snow scene with a snowman, a car covered with snow, and smoke rising from the chimney of a house blanketed in snow. His right hemisphere processed that picture.
On the table they had spread out eight cards, each with a different object: a lawnmower, a rake, a shovel, an ax, an apple, a toaster, a hammer, and a chicken head. They asked Paul to point to the card that went with what he had seen on the screen. His left hemisphere directed his right hand to pick the chicken head; it went with the claw. His right hemisphere directed his left hand to pick the shovel; it was associated with the snow scene.
When the fiber tract is cut, neither hemisphere knows what the other hemisphere knows. The information cannot get through to the other side. Thus, each half makes a different association to what it has seen. Each hemisphere is unaware of the fact that the other hemisphere is responding to an altogether different scene.
After Paul had selected the shovel and claw, a researcher asked him, "Why did you do that?" meaning, Why did he pick the different pictures? Without a moment's hesitation Paul looked at him and said, "Oh, that's easy. The chicken goes with the chicken head and you need a shovel to clean out the chicken shed."
What had happened?
Because the left brain handles the right side, both input and output, we can understand how the claw went with the head. Because the right brain handles the left side, both input and output, we can understand how the snow scene got linked with the shovel. How, though, did the shovel—the right hemisphere's association to snow—end up being needed to clean out the chicken shed? How did the chicken—the left hemisphere's pairing of claw and head—end up representing a chicken shed that needed cleaning out?
What happened to the snow? Where did the shed come from? Why was the shed dirty? How did a snow shovel become a shovel for a chicken coop?
The Interpretive Left Hemisphere
Patients like Paul help answer such questions. In most people, the left hemisphere is the talking half of the brain. It is the source of active speech and words. If it is damaged, active speech is affected.
From the mid-1800s to the mid-1900s scientists called the left brain the "major" hemisphere. It could talk. All that mattered was the ability to speak. They thought of the right hemisphere as "minor." It was silent. Later we say more about this unexamined assumption about what is important in human experience.
For now the important fact is this: when the fiber tract is cut, the right hemisphere cannot say what it knows, nor does the left hemisphere know what the right hemisphere knows. The main communication line is down. Hardly any inside information passes between them.
The right brain could not let the left brain know about the snow scene directly. Even so, by pointing with the left hand it could still associate the scene in the slide with a card on the table. The act showed that the right hemisphere knew what it saw. At the same time, although the left brain did not have access to what the right brain knew, it could still handle the task of explaining why the hands behaved as they did. The left hemisphere knew why the right hand picked the head—because of the claw. Although ignorant of the snow scene, it did observe that the left hand picked the shovel.
To answer the question, "Why did you do that?"—referring ambiguously to the two different cards—the talking hemisphere had to make sense of two sources of information. First, there was the information it knew directly. Second, there was what it observed and thereby knew only indirectly. At the same time, the silent hemisphere knew that it had seen a snow scene because it used the left hand to select the shovel. Although the researchers kept the two hemispheres in the dark about this little trick, they knew what was going on because they had set up the experiment.
The snow scene/shovel connection is a relatively neutral one. It may trigger a feeling of being warm, snug, cozy, relaxed in the midst of a gentle winter day. The shovel may lead one to think of needing to shovel the walk. Taken together, the paired pictures are not likely to work one up into a state of excitement nor throw one into a state of despair. They are simply there as objects of information—connecting stimuli with responses.
From an emotional point of view, the shovel was merely a tool for which Paul had to account. The explanation was cognitive, rational, and logical. No significant amount of feeling was evident. Even so, Paul's response suggests that the brain—most particularly the talking left hemisphere—acts in a meaning-making way. It observes what is going on, and in the very act of observing it assumes there is some relationship—some reasonable connection—among the separate items of information at its disposal. A meaningful connection constructs an explanation—creates a story—even if that explanation is faulty. In short, the left hemisphere is the interpreter of our experienced world, but from a vantage point that observes from the outside.
The Hunger for Pattern
It seems that nothing can be innocuous enough to abort that explanatory process. Asked to figure how a series of random numbers go together, people agonize over the task. They arrive at a solution, explain it, and when informed that these are random numbers, they still insist there is meaning in the order. Unless especially trained to do so, our brain simply does not allow for the possibility of unconnected or random experience.
George Johnson, science writer for The New York Times, describes our brain's ability to detect elusive patterns as a "hunger for pattern ... even when it isn't there." In the mid-nineties, astronomers cautiously announced evidence of regular pulses of radio waves, which subsequent research showed were not always so regular. Similarly, giant accelerators send beams of particles—protons and antiprotons—crashing into each other in order to sift the resulting debris for patterns. The issue, according to Johnson, "is separating order from randomness, weeding out false positives—the patterns that leap by chance from the background noise." This hunger for pattern calls forth such ideas as "canals of Mars" or "the man in the moon," or "the shovel is to clean out the chicken shed." Our human brain—with its imaginative symbolizing predisposition—is constantly sifting the messy world of randomness for the "tiniest hints of order."
If meaning-seeking is present in ordinary experience, what does an emotionally laden element add to the experiment? Is the resulting explanation as straightforward as "Oh, that's easy [which means easy for the talking brain]. [The left brain saw the claw; it knew that. Therefore,] the chicken claw goes with the chicken head [which the right hand picked.] And [because the left brain saw the left hand pick the shovel it knew the shovel had something to do with what was happening. Therefore] you need a shovel to clean out the chicken shed." The inference allows one to make up a perfectly sensible scenario if one knows about a claw, a head, and a shovel and does not know about a snow scene. Does emotion affect the explanation?
A similar experiment with a woman split-brain patient suggests an answer. In the midst of a series of rather dull items being flashed on the screen, the researcher showed a picture of a nude woman to her right hemisphere. When asked what she had seen, she reported, "nothing." Her left hemisphere, of course, had no knowledge of what its counterpart was seeing, so it had nothing to say. At the same time she blushed, squirmed, smiled, looked confused and uncomfortable. Her right hemisphere was reacting emotionally to the nude picture.
|List of Illustrations||ix|
|Introduction: Toward a Neurobiology of Meaning||xix|
|Part 1||Linking the Physical and the Imaginative|
|1||A Neurobiology of Faith: The Primal Urge to Know and the Primal Urge to Relate||3|
|2||"Mind" as Bridge between Religion and Neuroscience: The Brain as Physical and Relational||29|
|Part 2||The Working Brain and God's Ways of Being God|
|3||The Upper Brain Stem, Attending, and an Ever-Present God: The Reptilian Brain in Arousal||51|
|4||The Limbic Lobes, Relating, and a Nurturing God: The Mammalian Brain in Play, Nurturance, and Motivation||71|
|5||The Limbic System, Remembering, and a Meaning-Making God: The Mammalian Brain in Memory and Self-Relatedness||90|
|6||The Neocortex, Organizing, and a Versatile God: The Right and Left Brain and the Search for Understanding||110|
|7||The Frontal Lobes, Intending, and a Purposeful God: The Human Forebrain in Empathy, Goals, and Prioritizing||132|
|Conclusion: The Mind-Producing Brain, Sin and Evil, and God as All-in-All||153|
|A Glossary for Religion||187|
|A Glossary for Science||191|
|About the Authors||235|