Monday, April 18, 2011

The bicameral mind

What was mental life like before the breakdown of the bicameral mind?  We know what it's like afterward because each of us lives in a modern, post-breakdown mind.  But before was very different.

In the bicameral mind, the two hemispheres had evolved into two very different beasts.  As today, the left hemisphere was in charge of interacting with the world.  It controlled the process of speech.  It controlled the right hand, the hand that reaches out, the hand that tests the world, the hand that grasps, the hand that manipulates the pieces of the world.  It is not clear what else the left brain did.  What it didn't do was perceive or think about itself.  Without a sense of self, the left brain was free to act much as it does today, but without regret.  It probably was the source of the symbology (hieroglyphics) that are seen in the works of the ancient Egyptians, who lived before the breakdown.

As today, the right hemisphere perceived reality directly through the senses and lived in the flow of the world.  It learned and kept all the knowledge of how to survive and prosper in whatever world it lived in.  It knew where the stars reside in the sky.  It knew the myriad plants in the surrounding natural world.  It knew how to nurture growth in a garden or field and how to avoid predators.  In fact, it seems much like our present right brain.

What was greatly different before the breakdown was how the hemispheres interacted.  Remember that the corpus collosum, which is the primary connection between the cortexes of the two hemispheres, is relatively small compared to the things it is connecting.  Jaynes proposed that the primary communication crossing the corpus collosum before the breakdown was words.  He found that the area of the right brain corresponding to Broca's area (the left brain's speech center) is also capable of  speech even though it is not connected to the vocal centers.

Jaynes proposed that the right brain literally spoke to the left brain.  The left brain perceived this speech as coming from outside of the body and deemed the speech to be coming from a god or gods.  The content of the speech was largely imperative: do this, do that, don't do the other thing.  The left brain listened and obeyed.  Without a sense of self or ego, there was no resentment against the voice.  Moreover, the voice was generally right, meaning that what it said to do needed to be done for a good reason: planting, making offerings, and otherwise contributing to the community.

As today, the right brains of a community were closely integrated with one another.  Mostly, all the right brains in a community saw things the same way, so they behaved as something like a "hive mind", with each right brain directing its left counterpart to perform the actions which would benefit the hive.  Conflict among the members of a hive was uncommon since there was a shared vision and no egos to get in the way.

This is not to say there was no conflict.  Geographically separated hives were not likely to share the same sensibilities, so when they came into proximity they might fight or otherwise act out their differences.

Life before the breakdown wasn't idyllic: survival has always been hard.  But people didn't feel sorry for themselves or resentful.  Nobody was taking advantage of others, so if a group suffered, it suffered together.  When there was bounty, as during early Babylonian and Egyptian civilizations before the breakdown, people naturally organized themselves in to efficient hierarchical civilizations, with right-brain communication holding each level of the hierarchy together and connected to its leaders.  Jaynes proposed that the voice a person heard sounded like the voice of the leader in the hierarchy.  An ordinary person didn't separate that from the voice of the god that person represented.

The pyramids of Egypt were built well before the breakdown, and none were built after.  The mystery of how the pyramids were built makes more sense to me as a product of a hive mind living in a bounteous time than any other explanation I have heard.  We know the pyramid builders were not slaves, and they showed an amazing amount of organization over an extended time.

Thursday, April 14, 2011


So far I have described the modern view of how the two brains work, but I said when I started that I would say more about how we got here.  The next step in our journey is The Origin of Consciousness in the Breakdown of the Bicameral Mind.  First published in 1976, this is the book that made the separation of the brains a big story.  Research had shown throughout the 20th century that there was considerable difference between how the two brains worked, but Julian Jaynes provided the first comprehensive story about what the difference was and how we got here.  Iain McGilchrist (Master and Emissary) credits Jaynes with raising the issue of two brains and speaking cogently about it, even if he has some disagreements with some of Jaynes' findings.  If you are interested in how the two hemispheres came to be what they are today, you should read The Origin of Consciousness (OC) just to understand the issues, whether you believe his fantastic theory or not.

The first issue to consider is the meaning of consciousness.  Consciousness is used to refer to many aspects of brain/mind function, and there are as many definitions of consciousness as there are psychological theorists.  In order to understand The Origin of Consciousness, you must adopt Jaynes' definition of consciousness, if only temporarily.  I happen to think his is a fine and useful definition, but it is certainly not the only one.

Julian Jaynes defined consciousness as the internal sense of "I" existing in time, with all the internal verbal conversations that come along with that.  His definition is actually more complete and precise than that, and I encourage you to read OC to understand it more fully.  His definition doesn't refer to cognition or creativity, just to the sense of self around whom all stories are built inside the mind.

Jaynes proposes that we didn't have that sense of self until about three thousand years ago.  Before that, the sense of self and "I" didn't exist, in what he calls the "bicameral mind".  About 1200 BC there started a revolution in how the mind works, referred to as "the breakdown of the bicameral mind".  As a result of the breakdown, each of us gained a sense of self and new way of thinking.  Internal human life changed dramatically, and the modern world was born.

All of this is highly improbable by any rational measure, yet it seems to be the only comprehensive theory of human consciousness and history of neurological function on the table.  No one else has proposed, much less made headway with, a comprehensive alternative explanation of all the historical and modern evidence of who we are.  I won't ask you to believe all this: it is just too fanciful.  But you should consider it.

Monday, March 21, 2011

Leaping the chasm

In the previous post I presented the modern dilemma as seen from the perspective of the left/right brain divide.  It ended with the pessimistic statement "we are stuck where we are", which is the logical conclusion of the left brain.

I don't believe we are stuck.  There are many leaps possible, and more people are understanding the need for leaping.  If you are concerned about where we are heading, make your own leap.  Encourage the leaps of others.  If nothing else, refrain from keeping others from leaping.

More to come.

Sunday, March 20, 2011

Cultural divide

In the previous post I described the balance between the use of the hemispheres in various creative endeavors.  Nearly all creative acts require both hemispheres to work in concert, but different media can engage the two differently.

In this post I intend to show that how we think about and live in the world affects the world, and vice versa.

First, here is a very terse and over-simplified summary of the balance of left and right brain in various stages of western civilization as identified in Master and Emissary.  Each stage has had a very different culture, based on the predominant thought patterns of the day.
  • Artistic expression started in pre-history as a left-brain phenomenon, though the rest of life was mostly right-brain.
  • By the time of ancient Greece, artistic expression had been integrated into the right hemisphere.
  • By the time of the Classical age, the left brain became dominant in areas outside of art.
  • Rome in the Augustan era (~1AD) was notably right-brained.
  • The rise of Roman state Christianity coincided with a shift to the left brain.
  • The Middle Ages were marked by intense rationality (left-brain).
  • The Renaissance marked a large swing to the right brain.
  • The Enlightenment was a large swing back to the left brain.
  • Romanticism was a swing back to the right brain.
  • The Industrial Revolution required and nurtured the left brain.
  • Modernism and Postmodernism reinforced the left brain.
So we find ourselves in a left-brain world.  McGilchrist suggests the possibility that we are stuck here because so many cultural forces, most notably technology, supported by postmodern art, conspire to keep us here.

How does culture affect our use of our brains?  I described in a previous post how the brain "chooses" which of many thoughts to express.  While the brain is not a blank slate, this "choosing" is subject to learning, and most of us learn to "choose" based on the dominant culture in effect when we grow up.  The culture is expressed through parents, teachers, friends, media, and institutions, and we proceed to both express the culture and impress it on those around us, including our children.  Thus culture is perpetuated in a reinforcing feedback loop.

Our "choosing" is a delicate balance: small changes can make big differences.  Small changes away from the cultural norm generally elicit negative feedback from society, restoring the norm in almost Darwinian fashio.  Small changes that support the cultural norm are often adopted, intensifying the norm.  McGilchrist argues that the natural tendency of the human mind is to restore the left-right balance, as shown by the variations over history.  But this tendency must contend with the restorative power of the cultural norm.

Our current culture is very left-brained.  Technology is pervasive, and almost every interaction with it draws us into our left brain as our eyes parse the ever-changing abstract screens on our computers and cell phones, then make our fingers run an obstacle course through arbitrary numbers and words.  Art challenges us with ever more abstract re-presentations of reality, taunting us with obsolescence if we can't analyze the latest deconstruction of the body and mind.

People aren't happy with the current state of the divide.  Our personal lives are chopped up into tiny familial pieces when our right brains crave community.  As part of my work I have seen studies of how people would prefer to relate to technology, but the cultural norm keeps those changes from happening.  Young people immerse themselves in games that exercise the right brain.  Yet complex games are now losing force to the imperfect forms of socialization and connection: Facebook and Twitter.  The tyranny of the desktop computer interface is losing to the slightly less insulting smart phone.  People vote with their feet and dollars, but they can only vote for what's on the ballot, and the choices are limited.

I will suggest that the energy engaged by the Tea Party movement is a reaction to the overly analytical world those people face.  (Ironically, the effect of the Tea Party movement, as guided by its moneyed masters, is to reinforce the cultural norm, but that's another story.)

One effect of an unbalanced divide is that we don't think straight, either individually or as a culture.  This means that when we are faced with difficult or catastrophic problems, we neither see them clearly nor respond to them effectively.  In a left-brained world, when the problems continue or get worse, we will analyze them further, perhaps to death, when no amount of local optimization will improve things, and only a wild leap to another place will help.  The left-brain will never leap, so we are stuck where we are.

Saturday, March 19, 2011

We all use both

When I first heard about "right brain", I wanted to be there.  I thought living in my right brain would make me more creative.  (I even use 'rightbrain' as my login some places.)  Now I learn that we all use our right brain all the time, so I started to consider the issue in a different light.

If we all use both, what determines the balance, and what affects the balance?  Master and Emissary has a very compelling description, which I will try to summarize in the next few posts.  First, let's consider some perhaps counter-intuitive implications of the divide.

Are novelists and playwrights writing from their left or right brains?  The written medium is all words, which would seem to be the province of the left brain.  Furthermore, the works (novels and plays) are linear, and linearity is the hallmark of the left brain.  The answer is that they use both in exquisite cooperation.  The best novels and plays are about grounded reality, which only the right brain can provide.  They evoke images in the reader's mind, and only the right brain can construct those images in words.  They employ metaphor, which only the right brain understands.  They offer humor, which is primarily a right brain function.  The left brain works with the right to linearize the story and put it into words on paper.

When we read a novel or see a play, we are also using both brains.  The left occupies itself with the words, leaving the right brain to immerse itself in the story.  The right brain understands language, but in a different way than than the left.  Language understanding in the left hemisphere is concentrated in Wernicke's area, which unpacks language in a manner similar to how the left hemisphere Broca's area packs it into speech.  Language understanding in the right hemisphere is more diffuse, connected more to meaning than syntax.  It is the simultaneous understandings of the left and right hemispheres that creates the rich and fulfilling response to a well written novel or play.

Non-fiction writing can have a different balance.  Telling a true story can be as evocative and compelling as any novel or play and the effect will be as balanced as they are.  However, much non-fiction writing concerns itself with how the world is constructed, and this appeals more to the left brain.  Some non-fiction writing is really communication of left brain re-presentations from the writer to the reader, in which case the right brain is hardly involved.  Most people find such writings hard to read.

Poetry can bypass the left brain entirely.  Most poetry offers some balance to the left and right brains, but the preponderance of metaphor leaves the right brain somewhat confused.  Some poetry offers no meaning to the left brain, in which case the left brain either shuts down or panics.  The right brain doesn't demand meaning, so it is free to rest in the shape and evocation of such poetry.  How we feel about a poem often depends on the ability of our left brain to disengage rather than rebel.

Creating and appreciating a piece of artistic pottery can also bypass the left brain.  Creation requires only the free flow of expression from the right brain to the hands, and appreciation is often just as pure.  But the picture is not so simple as it might seem.  The best pottery involves a bit of invention, and that is done with the right-left-right paradigm, often in a series of "failures" that are destroyed before the end result is ever seen.  So even the most pure artistic achievements are usually the result of the collaboration.

I write software for a living.  This last year I wrote a CAD system that ran to many tens of thousands of lines of code.  I carefully paid attention to the work in order to understand my own creative process.  I couldn't keep track of all the individual pieces of the project, but I never lost my overall understanding.  My head would ache while I puzzled some difficult problem, which I interpreted as my left brain being unable to cope.  At such times I would often take a break or go home, and most of the time when I got back, I would have a solution.  I interpreted that as my right brain working on the problem without my conscious involvement.  Left brains, including mine, are only capable of handling a limited amount of complexity.  Right brains have no such limitation.  Even engineering can involve high levels of coordinated activity between the hemispheres.

In fact, just about every creative act involves substantial involvement from both our brains.  Sometimes we just don't admit it.  How we see our brains working together can influence how we treat ourselves.  More importantly, it can affect how we treat others.  If we see our own success as a result of our left-brain analytic abilities, we will encourage and reward others based on our perceptions of their analytic abilities, and we will teach them only analytic skills.  If we see our own success as a result of our right-brain reasoning skills, we will encourage and reward others based on our perceptions of their reasoning abilities, and we will teach them only reasoning skills.  All of us need both, and our prejudices and misunderstandings on this issue can determine the future, as we will see in the next post.

Friday, March 18, 2011

How the left brain behaves

The left brain is easier to describe since it's all about words.  The left brain has a narrower, more focused, and 2D view of the world.  It only sees a small inner portion of the right visual field, corresponding to the small area of the cones.

The right brain is always finding things for the left brain to attend to.  It mostly does this by turning the head and eyes to look at something.  Whatever is inside the visual plane at the time of looking is either recognized or decomposed by the left brain into smaller bits until some bit is recognized.  Left brain recognition consists of mapping the recognized bit(s) into a set of symbols.  This is often done with context provided by the right brain.

The left brain carries a huge number of symbols, and it keeps track of a large number of relationships among the symbols.  So the right brain is able to recognize a plant, but it might not be able to recognize what to do with a seldom- or never-seen plant without the left brain turning some of the details of the plant, like leaf shape or color, into symbol references and connecting them to symbolic references to other plants in memory.  The left brain combines the recognized and referenced symbols to form a sense of the new plant and create a new symbol to represent the plant.

The left brain doesn't create a new symbol for everything new it encounters.  If a new item is deemed to be very much like another, it will adapt the previous symbol to stand for both things.  This involves making connections from the new bits it encountered to the adapted symbol and modifying the adapted symbol to include the new bits.  Thus, every time we encounter a new tree, our symbolic understanding of 'tree' enlarges to include it.  So while the right brain is busy remembering the true image of the new tree, the left brain is remembering the new bits of the new tree and generalizing 'tree' to be even less like any real tree than it was before.

Most of the left-brain symbols are associated with verbal terms.  I say "terms" because the association may be with either a word or a phrase (or a collection of words or phrases.)  When a symbol is activated by sensory input, the word(s) and phrase(s) are conjured along with the symbol.

The left brain operates at two levels.  The previous paragraphs describe the first level, in which the limited sense inputs of the left brain activate symbols and create new ones.  The second level 'plays' with this rich symbol collection, informed by the activation of symbols by the first level.  This playing goes on all the time, sometimes directed by symbol activation ("I see the cat") and sometimes operating without sensory input (daydreaming.)  And many parts of the left brain may be playing simultaneously with different sets of symbols.

The second level of left brain activity is what we normally think of as consciousness.  It is a jumble of individual words, fleeting thoughts, story lines, planning, reviewing, judging, etc., all happening at once.  The elements of the jumble typically involve words, lots of words, competing for attention.

The primary attribute of all these verbal mental processes in the left brain is that they are all based on the left brain symbols, not sensory input directly.  McGilchrist in Master and Emissary calls this use of the symbols "re-presentation" in order to differentiate it from direct perception ("presentation" of the world).  This is one of the attributes that makes the left brain so powerful: it can see and play with a world that doesn't exist.  But it also separates the left brain from reality.  The symbols are always approximations of reality, sometimes differing substantially from it, and this can lead to problems.

One of the ways the left brain connects its symbols is linearly, as if in time.  I say "as if" because the left brain's concept of time is strictly "ordering", not flow.  Time in the left brain is discrete and not continuous.  Events unfolding over time in the world become in the left brain a discrete series of symbolic events.  This (re)ordering of events is especially useful for planning and carrying out plans.  The left brain can "play" with the ordering of events, even constructing orderings that it hasn't encountered before.  Then it can step through such a series of events and carry out very precise processes that have never been seen before.

With all the verbal mayhem going on in the left brain, there has to be a way for attention to be focused.  In a previous post I referred to this process as "choosing" without going into what it involves.  In practical terms "choosing" involves activation levels of neural networks in the left brain.  Each neural network corresponds to one of the elements in the verbal jumble referred to earlier.  The activation level of a neural network depends on many factors: the strength and number of symbol activations, the emotional impact of the activations, and the state (mood) of the brain (meaning what other networks are activated.)  Not least is habituation, in which activations that we experience more tend to happen more.  Unless a network is continually reinforced, its activation decays with time, so it will likely be replaced by another network/thought/idea/concept.  Thus our attention moves from thing to thing.

One of our many choices is to attend to the right brain view directly.  When this happens, the words stop, we notice our peripheral vision, and other senses may report.  We almost always then notice something interesting.  The right brain will usually direct the eyes to it, which almost always activate a left-brain, verbal network enough to start some story ("That's a cumulus cloud".)  So we tend not to attend directly to the right brain's view for very long before we find ourselves attending to one of the many neural patterns in the left brain.

One characteristic of left-brain activity is that it takes a bit of time.  Sensory input has to activate symbols, which in turn activate multiple neural nets, which then have to be arbitrated among, each step of which takes time.  While the right brain can mediate appropriate responses to stimuli in a handful of milliseconds ("duck!"), the left brain can take hundreds of milliseconds to appropriately attend.  Thus, our normal lives (walking, driving, lovemaking, etc.) are mediated by the right brain.  At the same time the right brain is performing these actions, the left brain is participating as a voyeur.  This leaves it free to think about things that have nothing to do with the activity at hand or create stories about the activity that may not be entirely true.  Even if it attends and doesn't prevaricate, its experience is at best a series of symbol activations.

This brings us to a central conundrum: the left brain lies.  When you ask a person about an activity, it is the left brain that responds, because it controls speech.  To answer the question the left brain will have to mediate among various activations that occurred during the activity, and the right brain view is only one of them.  The choice of what activation to report is a complex consideration of survival, advantage, habit, time to respond, and myriad other factors.  If the measure is objective reality, only the right brain view is true, and the left brain may not choose to report it.

Thursday, March 17, 2011

How the right brain abides

I wanted to provide a description of how the right brain resides in the world, but I failed.  To put it in a post, I have to use words, and words immediately make it all sound like the left brain.

If you want to get an idea of what your right brain is like, read My Stroke of Insight, especially the chapter "Morning of the Stroke".  At that point she was living entirely in her right brain, and she describes what she remembers it feeling like.  Of course, anything she writes is suspect because she has the same problem I do, her thoughts must be translated by her (largely recovered) left brain.  The description is also suspect because it is a description of a right brain that has just lost its lifelong partner, essentially a fraternal twin, and is both bereft and fighting for survival.

When you open your eyes, the right brain soaks in everything in the visual field.  It connects to the world it sees, and knows where it is in the 3D world.  It listens to the world.  It knows where the sounds come from, and connects the sounds to the 3D world it sees.  It feels every part of the world you are touching and adds that to its integrated understanding of the world.  The same with smells.  All this happens without any effort on your part, and it continues as long as you are awake. 

The right brain craves sensory stimulation. The head turns.  The eyes scan.  The fingers explore.  The body locomotes.  The right brain wants more connection.  It craves complexity.  The right brain will often rest in fractal complexity, such as a tree or a mountain or a flock of birds flying or a rich work of art or clouds.  The right brain sees a fully 3D world, with a full understanding of the concept of depth in all it perceives.

The right brain recognizes changes in the visual field.  In the periphery it will notice small changes in luminosity and shift the eyes (and head if necessary) to more fully see it.  It can recognize many things.  Some things like snake-shapes and spider shapes may come from our genes.  Others are learned (via the right-left-right paradigm).  For some of those things the right brain initiates instinctive or learned responses.  For others, it alerts the left brain.   All the while soaking in the world and seeking more.

The most complex thing the right brain recognizes is the face.  The right brain tries to find faces everywhere: human faces, pet faces, other animal faces, even insect faces, all turned at different angles.  It not only finds them, it identifies them from the subtlest of cues.  While it is identifying a face, it is also reading subtle (and not so subtle) emotional cues, so we can look at a face and instantly recognize what that being is feeling (though not flawlessly.)  Then we can tell where the face's eyes are looking in the 3D space that surrounds us.  Then we can read the dynamics of a face (and its body) to predict its behavior (again, not flawlessly), all before the name of the face owner pops into our conscious thought.

The same goes for all sensory fields.  The healthy right brain wants to touch and be touched.  It hears the environment.  It pays attention to the brain's mental states.  These things go on whether you are attending to them or not, and the right brain will try to get the attention of your consciousness when something interesting or important happens.

The primary effect of this robust connection with sensory input and attraction to complexity is that the right brain perceives connections with everything it surveys.  It doesn't 'think' about the connections in any conventional sense: it resides in those connections.  It a very real sense it is those connections.  The right brain doesn't perceive boundaries between itself and the world of its senses.  It doesn't even perceive boundaries between the various things it perceives.  It perceives patterns in a unified landscape of sensual data.

The right brain lives in time as much as it lives in the 3D space of its senses.  The right brain experiences time as a continuous flow of changing sensory input, reasonably calibrated with real time.  Events not only happen in order, but intermediate events are experienced and remembered for just about every two events.

The right brains spends its time and energy resting in the continuity of the connections it has with the greater world as the world changes over time.  It reports to the left brain many interesting patterns it recognizes, and it does this tirelessly, providing a reliable context for the more frenetic activity of the left brain.

Wednesday, March 16, 2011

Drawing on the brain

My first experience with the left/right divide was a one-day course "Drawing on the Right Side of the Brain" at SIGCHI 98(?).  Based on her book and a longer course, it was the first time Betty Edwards had tried to condense her originally multi-week course to a single day.  It worked for me.

During the course she referred repeatedly to L-brain and R-brain as metaphors because at the time medicine and psychology were busy denigrating any reality of left/right brain differences and she had clearly been beaten up by the "experts".  I haven't talked to her since then, but I'm sure the last decade's real research on the differences has gratified her.

There were two exercises that made an impression.  I hadn't read the book before the course, and came into the class doubtful that I could learn to draw.  The exercises had a profound impact on me.  I was able to draw, and I felt the mental shifts she described as necessary to do it.  I will briefly describe them here. 

The first exercise was to copy Picasso's "Portrait of Igor Stravinsky".  I have tried to copy other images in my life, so I was quite aware of my inadequacies in doing so.  The second exercise was to draw my hand, and I also doubted that I could do that.  But I was open to learning.

The trick is to copy Picasso's "Portrait" upside down so as to disengage the left brain.  I started in, and was really happy with how well I was doing, both in speed and accuracy.  Until I got to the hands.  Without thinking about it, I watched my drawing turn to crap.  I erased the crap and forced myself to look only at the individual lines.  Drawing each line segment very slowly, I faithfully reproduced the hands.  After that I relaxed into my previous speed and accuracy until I got to the head.  I was ready that time and went into the slow, one-line-at-a-time mode and finished the head.  Of course, this is all described in the book, which I looked at later.

The exercise allowed me to experience the switch between left and right hemispheres.  Surprisingly, there wasn't any feeling of clumsiness in my drawing hand when the change occurred.  Apparently the brain is well practiced at making the transition.  One lesson was how subtle and natural the change is.  A second lesson was how easy it is to induce the change once you know it can be done.  The third lesson was, of course, what a dramatic difference it makes.

During the second exercise (drawing my hand), I played with the change and became comfortable with it.  I became confident that I could do it in the future as need arises.  I don't often draw, but the lessons I learned have benefited my work every since.

The lessons also opened me to thinking about left/right brain issues.  The academic condescension that was rampant at the time in most cognitive literature kept me from reading more about it until recently.  Now it seems that a corner has been turned, so I am immersing myself in the subject.

The overall lesson from the experience was that drawing is mostly seeing.   Betty made the point that drawing isn't art, so learning to draw didn't mean we had become artists.  She sees drawing as a basic skill that everyone should learn, like doing arithmetic or using a keyboard.  This message is more subtle than you might think since many of our personal and social problems arise from not seeing clearly.

A corollary to the overall lesson is that most of us can really only draw well an actual (physical) object.  Asked to draw a house, we would best draw an actual instance of a house.  Asked to draw a person, we would best draw a real person.  Drawing a generic house or person will usually lead to an uninteresting result.  I don't know how artists draw things that are entirely in their heads.

Tuesday, March 15, 2011

Playing with the world

The primary activity of the left brain is deconstructing the world and using the resulting pieces to construct new worlds.  This is the primary method of all human creativity.  It's sounds a lot like playing with Legos, and it is, but there are crucial differences.  In this post I want to describe the world of the left brain, just as I described the world of the right brain in the preceding post.

People are playful.  We tend to think of playfulness as some sort of icing on the cake of humanity, but I believe it is fundamental.  Not everyone is playful all the time.  Nor do our histories talk much about play; they tend to concentrate on the serious business of survival and power.  That may be what history is about, but day-to-day life is about play.

This is not to say everyone's life is fun or even that most people's lives are fun.  Fun isn't the reason we play.  The reason we play is that we have no choice; it is our nature.

One primary activity of the left brain is exploring the world.  The right brain typically starts this process by moving the head and eyes so the central right visual field encompasses something interesting.  The first thing that happens is that the left brain finds boundaries in the visual field and interprets the space between and outside the boundaries as pieces of the world.  The left brain carries around a lot of re-presentation of previously found objects.  A re-presentation is a somewhat idealized memory of a class of objects, something akin to an icon.  That is, the first time the left brain sees an object it remembers it much as it was first seen.  After seeing additional versions of the object, it forms a more general image of the object that both represents the object and re-presents it in slightly altered form.  If a first level object is not recognized, the left brain will typically, look for boundaries in it, and continue the decomposition.  For example, the first time a person sees what might be a house in the distance, the left brain identifies the roof, walls, doors, windows, etc.

Once the visual field has been decomposed into recognized pieces, the left brain will hold the pieces in relation to one another and see if the pieces can be recognized as some reconstructed whole.  The left brain also carries around a lot of reconstructed wholes.  Again, these are re-presentations of classes of real objects.  Continuing the example, the left brain that sees the erstwhile house will discover that an object with a roof on the top and walls on the side, with windows and doors, is likely a house.  If the match is sufficiently decisive, the left brain will "decide" that it is a house and start deconstructing its constituent parts, discovering how the roof, walls, windows and door are constructed.  If the match isn't decisive, it may continue looking for matches to a whole and find perhaps "barn".

We can see these re-presentations by asking people to draw something that is not present.   "Draw a house".  Most people will draw an image of their left brain re-presentation of a house rather than a specific house.  This left-brain re-presentation will typically be recognizable to others, but won't be considered particularly artistic.  In fact, the drawing may be a better picture than what they carry around in their head because during the drawing we will be fixing obvious deficiencies like "shouldn't the walls and the roof meet?"

These collections of re-presented parts and wholes are the Lego-like building blocks the left brain plays with.  When the left brain isn't doing anything else, it creates new things from these pieces, and some of these new things are added to the collections of wholes that might be found during some later exploration.

Note that the re-presentations aren't really stored as parts and wholes.  We continually deconstruct and construct so that most parts are really constructed of smaller parts, and wholes are often constituent parts of more grandiose wholes.  Thus we understand that doors are really made of molecules, atoms, nuclei, quarks, fields, etc., and are parts of a house in a great city on a planet in a solar system in a galaxy in one of many possible universes.

One form of creativity is seeing things that others don't see.  This may result from a person having imagined (mentally constructed) something before others had actually seen it.  Another form of creativity is making a physical representation of an imagined something that has never existed before, even if it just a little bit better than something that did.

The reality of a creation is perceived by the right brain and made an important part of our right-brain reality and that of others around us.  Thus the creative process that started with the right-brain directing the visual field of the left brain to something "interesting" proceeds full circle to returning the fruits of creation to the right brain.  This enables the right brain to find more "interesting" somethings to direct the left brain to play with.

Traditionally, creativity is ascribed to the right brain while I have described it as a playful partnership of both hemispheres.  These observations are not really in conflict if you understand what artists and philosophers have been telling us forever: the foundation of all creativity is perceiving the world clearly.  They tell us that by this they mean seeing the world without the veils that cloud our vision and distort reality.  The right brain sees clearly, but few of us are brave enough to trust its view over that of the more familiar re-presentations that fill our minds.  So for most of us, trusting the right brain is at once the most creative act we will perform and the basis of all further creation.

The secret world

The primary activity of the right brain is learning and using all the connections between all the elements of our world.  These elements include all aspects of the natural world, all the constructions of man, all thoughts and feelings in our minds, and most importantly all the other people we interact with.

We are social animals, much more than we normally admit.  The only other animals that live anywhere near as densely as we do are ants, bees, and termites, and we call them social insects.  We have conflicts,  personal, familial, and national, but most of the time in most places we live together, often very close together, leading productive and fulfilling lives.

That's the right brain.  The right brain sees everything connected, including all the human beings it perceives.  You can't escape that socialization, though you can choose not to participate at various levels.  However much you choose to live apart, your life will be defined by that separation, and much of your right brain activity will be mediating that apartness.

The right brain has mirror neurons (watch this TED video: it's fascinating.)  This is really a fully integrated major subsystem that runs through much of the right brain, though it is mediated in the frontal cortex.  Mirror neurons allow us to fully understand what another person is doing physically.  When we see another person lift her hand, the same neurons fire in our brain that fire when we lift our own hand.  Likewise, when we see another person hurt her hand, the same neurons fire in our brain that fire when we hurt our own hand in the same way.  (See the video for the reason we don't feel the same pain.)

VS Ramachandran calls mirror neurons "The neurons that shaped civilization".  I call them the neurons that make us human.  Just about every other neuronal system has an analog in other animals.  So far we have only found limited mirror neuron activity in non-humans, whereas we are immersed in it.

Every second of our lives in which we are perceiving others, we are partially living their lives.  Our right brains take in every nuance of position, action, and reaction that the people around us present.  And they are doing the same with us.

This detailed and intimate observation allows us feed our theory of mind.  Theory of mind is not a psychological theory, per se, but a theory my mind holds about the content of another's mind.  I infer what the other person is thinking from the location and observed actions of the other, that is, my mind has a theory about the content of the other's mind.  Because the right brain is grounded in reality, it doesn't turn the theory of mind into "fact of mind".  It remains a theory, which is continually updated from further "observation".  Note that "observation" here means the intimate feeling of "mirror neurons", not rational seeing and thinking about it.  All unconscious in the right brain without effort, or even choice, unless we divert our eyes.

One of the most powerful aspects of mirror neurons is the observation of other people's eyes.  Our right brains typically maintain a 3D picture of where we are in the world.  The picture is so accurate and detailed that we can often correctly infer what another person is looking at by seeing where they are and where their eyes are pointing, even if the thing they are looking at is not visible to us.  This is an incredibly complex geometric calculation that our brains can perform in real time while doing other things.

One of the most notable aspects of mirror neurons is the observation of other people's faces.  Our minds express themselves richly in our faces.  Such expression is very subtle, and there may be dozens of aspects of our faces that embody that expression.  Our mirror neurons allow us to infer what thoughts we might have been thinking that created the exact movement of a specific facial muscle that we see on someone else's face.  To the extent that we are right, we gain insight into the person we are looking at.  We can also be wrong since we express ourselves somewhat differently.

The target of mirror neurons extends outside the body.  When we see a car driving down the road, we not only infer the state of the car but that of the driver inside, even if we can't see the driver.  And we do this for many cars all at the same time.  The amount we can infer about the state of the other drivers' minds is limited, but it is sufficient to allow us to safely drive in crowded cities and freeways.

Our babies are born into the secret world.  They are born with the skills to participate in it immediately.  They don't recognize a boundary between self and other.  There is only the secret world and all the wonders in it.  Parents who bond with their babies are being re-initiated into the secret world.  As the baby becomes initiated into the constructed world, learning words and concepts and proper behavior, the child is often forced to choose which world to attend to.  The secret world never goes away, but most of us, parent and child alike, lose touch with it as the child grows up.

It seems to me that a pack of canines shares a similar secret world communicated (mostly) non-verbally.  I don't know the exact nature of that secret world, but I suspect is similar to our own.  (For example, a dog can do the same 3D positioning trick I described above.)  I believe the reason dogs have been such successful human companions is that we can share some part of our secret worlds.

Whether we are walking down a crowded street or sitting at home with family, we are participating in a continual, omnidirectional communication with those around us, and the knowledge we infer from this is as real to us as any other sensory input.

The secret world is always there, but we are not often consciously aware of it.  The experiences and circumstances of our lives often teach us to disconnect our consciousness from the secret world.  There is a lot of emotional content shared in the secret world, and much of it is sad, and some of it is disturbing, so we learn to ignore it.  There are people who can't hide from the secret world, and there are many who never experience it directly.  But we all use the information from the secret world to allow us to live in (more-or-less) harmony with others.

Working apart

The previous post described the fundamental working relationship between the two hemispheres.  That dance is what makes us human.  But it's not the only relationship, nor even the best known.

The most public working relationship is that of the left brain speaking and acting for the whole brain.  As previously pointed out, speech is mediated by Broca's area in the left brain, and most physical interaction with the world (touching, grasping, manipulating) is performed by the right hand, which is controlled by the left brain.  This is why McGilchrist termed the left brain the Emissary.

The role of emissary means that the left brain is in a privileged role.  If you accept that the left and right brains work independently and process information in completely different modes, then we have to consider that the left and right hemispheres may respond differently to the same stimuli, and there may be a conflict between the two responses.  That raises the question of which response will be acted on with body and speech.

This is part of a larger question.  I have greatly oversimplified the operation of the brain up to this point in order to create an understandable narrative.  In fact, there are many parallel operations taking place in the brain at any one time, in both hemispheres.  The brain is continually responding to stimuli, and it is also continually "choosing" which responses to act on.  The process of "choosing" is not conscious but a complex equation involving both valence and arousal, which are in turn affected by context.  Valence and arousal are independent dimensions of neural activity.  Valence can be thought of as emotional content, and arousal can be thought of as emotional impact.  The "choosing" is a learned response to evaluating valence, arousal, and context in real time.

The right hemisphere "chooses" one (or a few) response(s) among the many possibilities to present to the left brain.  (I suspect one or a very small number because the corpus callosum that communicates the choice(s) is relatively small as brain pathways go.)  Then the left brain "chooses" among its many possibilities, which include the right brain response(s), what will be acted on by body and speech.  This puts the left brain in its privileged role.

This privileged role is what has led us to think of the left hemisphere as dominant.  When the left hemisphere is severely damaged, we lose much of our ability to connect with the world, so we seem from the outside to not be the same person or not even "there".  When the right hemisphere is severely damaged, we may talk and behave normally, and the loss of right-hemisphere function may not be so obvious to those who don't know us well.

It is a running theme on the TV series House that "people lie", and this doesn't mean the doctor believes people always do it intentionally.  Furthermore, most psychological research must also deal with this issue.  Reeves and Nass describe in The Media Equation how psychological experiments for the last 60 years have had to deal with the unreliability of verbal reports.  The issue is that the left brain is "choosing" what to say.  Generally, the most honest (and useful) response to most questions will come from the right brain since it is grounded in reality.  But the left brain may choose to answer based on one of the many filters and processes it contains, ignoring the right brain response.

So the words and actions the left-brain initiates may represent only a faction among the brain's thought processes.  Depending on ones life experiences, the distance between what is said and done may be miles from what is really going on in the brain.  This distance can range from normal diplomatic speech to full repression of feelings resulting from serious abuse.  These are learned responses to a complex world.  Typically that learning is seen as necessary for survival (or advancement) of the whole by the left brain.  But there are times when those lessons are not in our best interests.

Underlying the comments in this post is the assumption that the left and right hemispheres can carry multiple disagreeing thoughts and feelings.  In a healthy person, the disagreement is typically minimal or well handled by the "choosing" mechanism.  When the multiple thoughts and feelings diverge too much and are not handled well by our "choosing" mechanism, people feel considerable distress.  Very often the underlying thoughts and feelings can't be changed.  Then our only hope is to learn to "choose" better, and that isn't easy.

The left and right brains don't know the same things.  The right brain has memory of its grounded reality.  The left brain has memory of the its constructed reality.  There is some evidence that the right brain has access to what the left brain knows, but not vice versa.  This is consistent with the way that the right brain has access to the entire visual field while the left brain only has access to part of the right visual field, and the way that the right brain is aware of the entire body and the left brain is aware of only the right side.  If true, this access makes the right brain a more complete picture of who we are than the left brain, and this is why McGilchrist termed the right brain the Master.

The asymmetry of the left-right divide in communication makes thinking and talking about the divide difficult.  As I mentioned in my second post, the left brain can feel threatened by the exposure of its role and methods.  I will repeat that I am not trying to denigrate the value or methods of the left brain: for every inappropriate coping mechanism is embodies there was undoubtedly an existential crisis making it necessary.

Do not take anything I say to mean the two brains are competing.  They are both doing their best to protect and nurture our self as a whole, but they have very different views of the world and very different structures with which to deal with that world.

Friday, March 11, 2011

Working together

In most people the left and right brains work together to create a recognizably human being.  This wondrous dance is going on all the time, and the two hemispheres are always communicating with one another, but the communication isn't symmetrical.

The right brain is connected to the world, monitoring all the senses all the time we are awake.  When the eyes are open, the right brain takes in a huge amount of information, including all the peripheral vision.  Each eye has well over 100 million photoreceptors, the vast majority of them rods, which are very sensitive to light.  The right brain pays attention to all of them and reacts when enough of them change in various patterns.  The reaction often includes directing the eyes to turn toward the change and directing the left brain's attention to it.

The sense change might come from sound in the ears or a touch on the skin.  Whether the change comes from those or vision, the right brain often directs the eyes to the perceived 3D location (which only the right brain knows) and tells the left brain to focus its attention and 2D vision on that sight.

Typically, the left brains drops whatever it was doing and places its attention on the center of vision (right center visual field only).  It takes apart the visual field in a multistep process.  First, the left visual cortex decomposes the 2D image into its component parts.  Next, the decomposed visual field is passed through the various filters mentioned in the previous post to come up with an understanding or explanation or possibility of what created the change.  Note that this change in attention is at the expense of whatever was being attended to previously.

Meanwhile, the right brain continues to pay attention to the changed area using the entire visual field.  The right brain looks for threats to survival.  Some threats may be built into our genes: there's some evidence that snakes and spiders may fall into this category and that relatively simple pattern recognition can invoke this response.  Other threats are the result of learning from previous encounters.  Such learning can be embodied in right-brain pattern recognition that responds quickly by directing the body to flee or otherwise react.  A reaction that can be mediated only by the right brain reaction will happen very quickly, in most cases quickly enough to be successful.

Meanwhile the left brain will be decomposing the event both spatially and temporally.  This takes time, so the threat better not be imminent if the left brain is involved.  On the other hand, if it's a new threat, the right brain may not recognize it, so the slow, klunky analysis performed in parallel by the left brain may be the only thing that saves you.  And if you survive the encounter, the analysis by the left brain can be returned to the right brain as a lesson that will allow faster response in the future.

The interaction of the left and right brains was just now described in terms of threats, but the same description can be made for opportunities.  Suppose you are hungry.  Walking through the jungle or savannah, your right brain takes everything in and finds all the normal sources of food very quickly.  But what if there are no normal sources?  A sufficiently starving right brain will notice anomalies in the environment that don't reach the threshold for food sources and direct the left brain to consider them.  The left brain might deconstruct the anomaly and come up with a plan to turn it into food while the right brain continues to scan for known food and threats.

Thus the normal integrated operation of the two brains is for the right brain to direct the attention of the left brain to sensory anomalies while continuing to connect to the world, for the left brain to discover new aspects of the world based on those anomalies and return the new information to the right brain, and for the right brain to integrate the new information from the left brain into its larger world view for long term advantage.  I call this the right-left-right paradigm.  This process happens continually in healthy human beings, and this the process that has allowed our species to advance so radically for tens of thousands of years.

The left brain

In the last post I described most of the primary features of the right brain.  It may have seemed that I covered most of what it means to be human.  Now I will add the rest.

The left brain is much different than the right brain.  The difference is not a matter of degree but of purpose.  The separation of function in the hemispheres of our brains is critical to both our survival as individuals and our success as a species.

The left brain doesn't see the world.  It sees this and that and the other thing: fragments in space and time.   Beyond that, it sees the world through a multi-level haze of filters.  These filters come from previous experiences.  We experience these filters as moods, opinions, theories, convictions, prejudices, etc.  At any one point in time the left brain may be interpreting the world through any number of filters.

In the left-brain mode of perception we see what McGilchrist calls re-presentations.  These are constructions of the left brain based on the filters in effect at that time.  For instance, if you ask someone about her relatives, you will usually get answers based on the stories that she tells herself about them, answers that may not agree with direct perception.  This is a very difficult concept that will be expanded in a later post.

The left brain doesn't perceive the flow of time.  The left brain understands time intervals and events and can string those intervals and events together to create the illusion of the flow, but only as long as that string is maintained.

The left brain focuses attention.  It can choose a sense to follow.  With effort it can pay attention to two senses and connect their occurrences.

Specifically, the left brain can focus its attention on the central portion of the right visual field.  This is a relatively small area that roughly corresponds to densest aggregation of cones in the center of the eye, and only the right side of that.  The cones provide our highest resolution sight, so the brain focusing on something with this vision makes a powerful tool.

The left brains sees this area in 2D.  It doesn't sense or appreciate depth.  Note that this small area on the curved visual field approximates a flat surface very effectively, so there is no real loss of perception.

The primary feature of the left brain's 2D perception is the discovery and tracking of boundaries.  The left brain is continually finding boundaries of what is in its visual field.  In fact, it does this to the extent that the boundaries often become more noticeable and important than the entities they bound.

The primary activity of the left brain is to deconstruct and reconstruct the world.  Its view of the world starts with the accumulation of sensory fragments, and it proceeds to play with these building blocks to try and make sense of the world.  The result of this play is the moods, opinions, theories, convictions, prejudices, etc., mentioned above that become filters to further perception.

In effect, the primary activity of the left brain involves a feedback loop between viewing the world through filters and continually updating or reinforcing those filters.  More on this later.

The secondary activity of the left brain is to be the primary agent of action.  Much human action is verbal, and generally only the left brain has access to the voice.  The complex manipulations of breathing and the vocal chords required for speech are so complicated (taking up brain space) that it makes sense to centralize them in one place, and that place is Broca's area in the left hemisphere.  The next most common human action is touch, which involves touching something, grasp, and manipulation.  These actions are also concentrated in the left hemisphere, which is why we think of most people as right handed.

Memory in the left brain is problematical.  The left brain can only remember what got in past the filters, and what is remembered is a collection of fragments strung together with whatever form of organization was in effect at the time the memories were created.  The recall of memories from the left brain is often found to be faulty.   The filters obscure and misrepresent reality.  The filters in place during recall are often different from the filters in place when the memories were created, leading to misinterpretation.  And the organization of the fragments is subject to revision when the memory is recalled.

These are the primary functions of the left brain.  I hope you will note that healthy human beings are not characterized by either this or the right brain description.  Being human is a dance between the hemispheres that magically gives us the best of both ways of approaching the world.  In the next post I will start describing the interaction.

The right brain

In the last post I presented what is well known (and not particularly controversial) about the functions of the two brains.  In this post I will tell you what I think is happening.  Much of it is controversial. Most of it has some evidence, though I will not present the evidence.  If it resonates with you and you want to learn more, I encourage you to read the source materials for the blog, given in the first post.

First I will describe the right brain.  This is not arbitrary.  While neuroscience has previously referred to the left brain as the primary or dominant hemisphere, those labels are being called into question.  For example, in the book titled The Master and His Emissary, the master is the right brain, and the emissary is the left brain.  I hope you will agree after I describe this relation that this may be true.

The right brain sees the world as it is.  It perceives the world in concrete terms.  It doesn't interpret the world through any sort of symbolism or abstraction or rubrik.  It perceives the world in real time.  It doesn't form opinions about the world; it doesn't judge what it perceives.

The right brain sees the world as a flow in time.  One microsecond flows into the next, with no boundary or step.

The right brain perceives the world through all the senses all the time and integrates the senses into a single flow.  It doesn't focus on any one sense or any one sensation.

In the last post I said that the left brain only has access to the right visual field.  Further, it only has access to the center of the right side of the visual field.  I'll say more about that later.  I bring that up to contrast it to the visual access of the right brain.  The right brain has access to both the left and right sides of the visual field, and it has access to peripheral vision, which the left brain does not.  Thus, if the left brain is damaged, the right brain still has access to the full visual field, quite different from when the right brain is damaged.

The condition called asomatognosia illustrates the difference in perception.  A person with a right brain stroke, able to perceive only with the left brain, may be unable to perceive the left side of the body, depending on the extent of right brain injury.  If so, the person will often deny that the left side of the body even exists.  Such a person may complain that someone else is in bed with them, because that arm isn't theirs.  By contrast, a person with left brain stroke will generally not experience asomatognosia.  Such a person will have full body awareness, though sensation from and control of the right side of the body may be compromised.  The difference is that the right brain was aware of that side of the body all along and so has a memory of it.

The right brain sees the world in 3D.  This is aided by the availability of peripheral vision.  It knows how objects fit into 3-space and understands how they relate to one another.  It knows about depth and occlusion.  Note that this 3D view doesn't depend on binocular vision, which only works in a narrow range of near distances, so one-eyed people still see the world in 3D.  This 3D perception of the world comes from moving through the world and seeing how things change their relation as we move.

The right brain holds our true memories of the past.  These are sensual memories of the events that actually happened, integrating all the senses with the emotional context that accompanied them.  A recent 60 Minutes episode reported on "superior autobiographical memory", in which 6 people worldwide have been identified as able to recall every event in their lives.  It is likely that we all have some version of this kind of memory.  The issue is recall.

The right brain can extrapolate reality into the future.  This doesn't involve theorizing, it is just a continuous extension of current knowledge a few milliseconds into the future.  This is how a professional baseball player can hit a pitch when it is known that his eye-to-arm reaction time is much of the time it takes a baseball to travel from the pitcher's mound to the plate.  He doesn't "think" about hitting the ball so much as "seeing" it a bit early.  (And it's obviously not perfect.)  The professional baseball player also extrapolates the detailed body motions of the pitcher into an understanding of where and how fast the ball will arrive.  Personally, I've experienced catching something I knocked off a table, without any time to think about it.  These are all abilities of the right brain.

The right brain doesn't perceive boundaries.  In its 3D world view it doesn't see the boundaries between the objects we normally think of.  Moreover, it doesn't see a boundary between itself and the rest of the world.  It doesn't see itself as an active agent in the world.  It sees itself as continuously connected to all it perceives, including other people.

In the next post I will describe the left brain.  It is much different from the right brain, and I have hinted at some of the differences already.

Tuesday, March 8, 2011

The nature of the split

In the previous post I described the nature of the the split between left and right brain function in chickens.  In this post I will begin to describe the nature of the split in modern humans living in modern western society.  I will draw heavily on what I have read in Master and Emissary as well as some impressions from My Stroke of Insight.  Keep in mind that this is an area of controversy and subject to the biases of the left brain that is doing much of the interpreting and communicating.

First, let's go over some of the issues that are not controversial.

It is well known that the sides of the body are lateralized to match the lateralization of the brain, with the left side of the body, including the eye, being controlled and interpreted by the right hemisphere and the right side of the body being controlled and interpreted by the left hemisphere.  This is clearly demonstrated by strokes, which typically shut down one hemisphere or the other, and much observation has been made on this point.

Most people are right handed.  This means that most of their activities are mediated by the left brain.  It is also well known that speech is mediated by Broca's area in the left hemisphere, for which there is no equivalent area in the right hemisphere.  Thus most of our interactions with the world (reaching, grasping, speaking) tend to be mediated by the left hemisphere. The left hemisphere also contains Wernicke's area which is associated with language understanding.  This led early brain researchers to designate the left hemisphere as the dominant hemisphere.

"... so only left handed people are in their right mind!"  This canard is demonstrably false.  In most left-handed people, the functions of the two hemispheres are reversed, so Broca's region, etc. are in the right hemisphere, and the normal functions of the right hemisphere are moved to the left.  (See the previous post for a possible explanation.)  Since the functions are fully reversed, everything works just as in a right brained person, but on the other side.  For ease of communication I will refer to left and right brains as if everyone was right brained.  And then there are people who are ambidextrous (I'm one of them.)  Brain lateralization has not been well studied in ambidextrous individuals.

The visual field comes from both eyes, and vision from both eyes is combined in the occipital lobe at the back of the brain.  Each hemisphere processes the optic nerve from the other side of the brain, forming a complete visual field.  It is now well known that the left brain only has access to the right visual field.   Note that this is the right visual field (created by the occipital lobe), not the right eye.  Thus, if one eye is damaged, there is still a full visual field created by the occipital lobes.  But if the right hemisphere is sufficiently damaged, only the right side of the visual field will be available to the individual.

Beyond these physiological differences, the brains are known to specialize in what activities they attend to and mediate.  I will only touch on them, because in most cases the specialization is either not well understood or otherwise controversial.  Sometimes the difference is summarized as logic vs creativity, but we shall see that understates the complex interaction between them.  The left brain is more interested in rules and linear thinking, while the right brain is better at following and solving complex problems of living like driving a car.  Have you ever wondered how thousands of us can hurtle within a few feet of one another at high speed and not have more accidents than we do now?  Thank the right brain.

There are other aspects of how our hemispheres divvy up the business of living in the world that are well known, but these are the primary ones and enough for my purposes.  In my next post I will step into more controversial aspects of the split.

Monday, March 7, 2011

Two brains

(I finished The Master and His Emissary, so now I can continue my original intention.)

If you're reading this blog, you probably have some appreciation for the split between our left and right brains.  Or perhaps you are a skeptic.  In either case I will try to make the extent of the split clear, which might make you appreciate even more how well they work together.

As a point of poetic license I will refer to each of the two hemispheres of a single brain as a "brain".  I will refer to the left brain and the right brain, even though they are really integral parts of a unified brain.  I believe this poetic license allows us to understand the issues better by overstating the separation.  Later I will speak about the incredibly intimate way in which they interact to make a living being.

Much of this post is based on the Scientific American (SA) article "Origins of the Left & Right Brain" (July 2009) by Peter F. MacNeilage, Lesley J. Rogers, and Giorgio Vallortigara.  I encourage you to read the article.

It is important to understand that the left/right split in animal brains is ancient.  Nature has evidently found it valuable to provide largely unimpeded parallel processing for some critical functions.  Of course, the brain is split in several dimensions.  There are layers (brain stem, limbic system, cerebellum, cerebrum) that seem to have been added with time, each apparently providing some new capability.  For example, the cerebrum is only found in mammals.

But even before animals had a cerebrum there was brain lateralization in the cerebellum.  The SA authors contend that hemispheric specialization "was already present in its basic form when vertebrates emerged about 500 million years ago."  The left brain "was originally specialized for the control of well-established patterns of behavior under ordinary and familiar circumstances".  The right brain "was at first specialized for detecting and responding to unexpected stimuli in the environment."

They give examples.  Chickens have two ongoing higher level functions, survival and eating, and these appear to be lateralized in chicken brains (and other birds).  Typically, the right eye (left brain) specializes in finding food.  In that case the left eye (right brain) specializes in detecting threats.  The authors suggest that by specializing two hemispheres, chickens can more safely eat, perhaps since the security function can't be compromised to help look for food.  The authors report in a sidebar an experiment in which chicks were 'de-lateralized', in which case they were unable to do both critical functions simultaneously.

An interesting note here is that about 15 percent of chickens are reversed, that is, their right eye specializes in detecting threats and the left eye specializes in feeding.  The authors suggest that this is  so that predators don't easily learn the nature of their specialization and take advantage of it.  Note that this is about the same percentage of left-handed humans.

Like most physiological functions, the actual assignment of function to the two brains has varied over time and species, depending on the nature and level of the critical functions for each animal.  Neither I nor the SA authors are suggesting that the lateralization of our brains evolved directly from the specifics of the lateralization of chickens.  There are likely interesting paths of evolution that lead to both chicken and human lateralization.

I hope you now believe how ancient lateralization is and how extensive it can and has been.  I believe the separation of function in our two brains is no less substantial than that of chickens, and is no less critical to our own survival.

Wednesday, March 2, 2011

I started this blog while I was reading The Master and His Emissary: The Divided Brain and the Making of the Western World.  Then I decided I needed to finish the book before I wrote any more.

I hadn't anticipated the scope and impact of this book, which I would describe as having the same impact on the internal basis of modern life as Guns, Germs, and Steel: The Fates of Human Societies has on on the historical basis.

It took me longer to finish M&E than I thought.  It is a thick book: 460 pages, plus 120 pages of end-notes and bibliography.  It's well written, if a bit esoteric (e.g., it doesn't always translate the non-English phrases it presents.)  But the length and erudition weren't the reason it took so long.  I was continually blown away by the revelations and implications of the book: I had to put it aside to assimilate, and sometimes cry.

I'm not actually finished with the book, but that's another quirk of mine.  Often with a book I really enjoy, I don't want it to end.  The book can't get any longer, but I can delay the finish and stay in the ambiance of the book a bit longer.  (I did this with Life of Pi for several weeks, making the amazing finish all the more powerful.)

One impact of M&E is that I will probably write about it more than I was expecting to.  However, it still doesn't seem to tell the whole story, so the other books I mentioned are still relevant.

Sunday, January 9, 2011

The problem with talking about the brains

Some things have been written about the two brains, and some, like Betty Edwards' book, have caught on for a short time, but then we tend to put the matter aside.  Why is that?  What could be more important than understanding how our brains work and how they affect and are affected by our lives.

The answer is quite simple: most of our verbal communication and much of our conscious attention is mediated by the left brain, and the left brain doesn't like the conversation because the truth seems threatening to it.  I hope your left brain doesn't take offense at what I write so you can keep reading.  If you keep reading, your left brain will find that I am not attempting to bypass or denigrate the left brain but help it find its place in concert with the right brain.

How can I write about the brains hemispheres honestly?   I'm largely ambidextrous.  I write with my left hand, but use a fork with my right.  I throw left handed, but I bat right-handed.  In other words, I'm a mess, and that may be what it takes to write about this subject.

How do we use our two brains?

I've been interested in left/right brain dynamics ever since I read The Origin of Consciousness in the Breakdown of the Bicameral Mind  in the late 80s.  Then I took a drawing class from Betty Edwards in the late 90s.  Lately I've been reading a number of other books that tell various stories about how the left and right brains interact.  They all tell different aspects of the story, and I believe I can tell a story that ties them together into a consistent narrative.  In the process we will see a fantastic (in the full meaning of the word) story about our origins as a species.  You will have to decide whether something fantastic can also be true.

The books I will try to integrate are:

I am not especially well read, so there may be other books that bear on this subject.  Please let me know about them.  I am not academic, so the presentation may be a bit haphazard.  I am not compulsive, so there may be factual errors. 

Each of the authors of the above books has his/her own point of view, and I urge you to read the books to discover it.  I may mention their points of view in passing, but I will primarily be presenting my own point of view, not theirs.  I have no idea whether any of them will agree with my thesis.