The Four Regions of the Thinking Brain Made Simple - Part Two

As I explained in my previous post, there are four general areas of the brain's cortex (thin outer layer) that handle four unique kinds of thinking. To understand these functions, it will help to understand back-brain/front-brain differences, as well as left-brain/right-brain differences.

Back-brain and front-brain. In simple terms, the back part of the cortex takes raw information from the senses and processes it into sight, sound and physical sensation. This gives us perceptual awareness — the ability to experience the world directly, to have real-time concrete images, feelings, names, facts, data and other practical details.

The front brain and the back brain are physically separated by the motor strip, a band of cortex that goes from ear to ear across the top of the brain. The motor strip sends action commands from the cortex to every part of the body. This creates behavior. Thinking in both the front cortex and the back cortex informs these commands, although the processing in both areas is profoundly different.

The back cortex has three main regions: occipital (visual/sight), temporal (auditory/sound) and parietal (kinesthetic/feel and touch). There is also an area that touches on each of these three main regions to coordinate the different types of perceptions into a total experience.

While the back brain produces instinctive stimulus-response reactions, the front brain facilitates decisions based on association and analysis.

The front brain also receives input from the back brain to relate it into categories, relationships and patterns. These units of meaning aren't perceptual. They're conceptual. In other words, the front part of the cortex "makes sense" of perceptions created by the back part of the cortex. Images, facts, emotions and other perceptual input are related to each other. These associations are stored in long-term memory as "knowledge" - meaningful conceptual patterns.

While other mammals have some front-brain tissue, the human front-brain cortex is much more extensively developed, giving us dramatically advanced learning, imagining, reasoning, problem solving and planning ability. Still, this wonderful capacity is not more important to survival than the products of the back brain, which produces perceptual awareness — the essential input for the front brain.

Left-brain and right-brain. The left and right sides of the cortex are physically separated by the corpus callosum, a bundle of nerves that let the two halves communicate with each other. We experience both input at the same time, creating the rich experience of our individual consciousness.
All language functions — hearing, understanding, forming, speaking, reading, and writing language — are clustered on one side of the brain. We call this the "left side" for convenience, because for the vast majority of people, the language areas are on the left side.

The presence of language processing on this one side of the brain has a profound impact on the thinking that goes on there. The act of naming things is unique to humans. The categorization of experience, using the names of things, creates a mechanism for order and structure that is the foundation of logical thought. Reason is essential to understanding cause and effect, analysis, problem solving objective, evaluation and decision-making.

Logical thought may be distinctly human, but it isn’t the only effective way of thinking. The right brain thinks by associating images. This highly useful way of sorting experience and creating meaning is how the right side of the brain processes information, learns, imagines, makes intuitive decisions and triggers action. It’s the basis for human creativity, artistic judgment, value judgment, intuitive judgment, interpreting behavior and recognizing complex patterns.

Neither left-brain nor right-brain thinking is superior to the other. Both are essential to survival and work together to help us make our way in the world. If a person was lacking either one of these ways of thinking, he or she would be radically disabled and have trouble functioning in society.

Now you can see why there are actually two different back-brain perceptual areas - the left-back and right-back, and both of them handle different kinds of concrete, "specific, concrete" thinking - what things are.

And there are two different front-brain conceptual areas - the left-front and the right-front, and both of them handle different kinds of "big-picture" thinking - what things mean.

In my next post, I'll describe what makes these four areas unique.

Post by Dennis E. Coates, Ph.D., Copyright 2011. Building Personal Strength . (Graphic from Performance Support Systems, Inc., used with permission.)