[Paleopsych] Revenge of the Right Brain

Alice Andrews aandrews at hvc.rr.com
Mon Apr 25 13:52:07 UTC 2005

I'm beginning to see it more as a continuum of cerebral variation. Chris McManus, in his awards-winning book Right Hand, Left Hand (2002), explains that although there's oddly little research done on the genetics of handedness, and 'brainedness', there is good reason to believe there are genes responsible for hemispheric dominance, lateralization and organization. According to McManus, there is a left-handed gene and it is known as the C gene; the right-handed gene is known as the D gene. Three manifestations of the alleles are possible: CC, DC and DD. Most CC individuals will be left-handed but also may be susceptible to such things as dyslexia, stuttering, autism, and schizophrenia. These individuals make up about 4% of the population. Most DD individuals will be right-handed and make up 64% of the population. And finally the DC individuals (32% of the population), will be right-handed and left-handed. 

McManus writes:

"In looking for an advantage for the C gene-and specifically for the DC genotype-a good starting place is the most striking feature of the C gene: its ability to confer randomness on the organization of the brain, not only for manual dexterity and language.but almost certainly for a host of other cerebral symmetries, such as those for reading, writing, visual-spatial processing and emotion. Although it might seem paradoxical, randomness, at least in small amounts, can benefit complex systems."

His theory of random cerebral variation "provides an explanation," he explains, "for the lay belief that some people literally 'think differently' or have their brain 'wired differently.' In a nutshell, McManus characterizes the DD brain/mind as "the standard textbook description" and having the "cold certainty of an ice crystal." For McManus, every DD brain is effectively built the same way and that about 2/3 of the population have such brains/mind. The DCers, in contrast, have modules all over the place, their brains neither lateralized nor compartmentalized the way DD-brainers' are. What this randomness means is that there's a good chance you get a kind of creativity you might not have gotten otherwise. Here are a couple of his examples, but there are many:

Say a DC individual has "a module specialised for understanding emotions located in the left hemisphere rather than the right, so that it now sits alongside left-hemisphere modules involved in the production of spoken or written language, that might be beneficial for writing poetry or being an actor....Or "imagine that a module for understanding three-dimensional space is in the left hemisphere rather than the right, so that it is now located alongside modules involved in fast, accurate, precise control of the hand; that might well benefit drawing or the visual arts, or perhaps ball control in sport." (p.231)


  ----- Original Message ----- 
  From: Thrst4knw at aol.com 
  To: paleopsych at paleopsych.org 
  Cc: Euterpel66 at aol.com ; ToddStark at aol.com 
  Sent: Monday, April 25, 2005 9:40 AM
  Subject: Re: [Paleopsych] Revenge of the Right Brain

  In a message dated 4/24/2005 10:07:41 PM Eastern Daylight Time, ljohnson at solution-consulting.com writes:
    I thoroughly disagree with the premise. First, the idea of right-brain / left-brain has been thoroughly discounted. Second, the author is creating a false dichotomy. Most technical people are creative and artistic. Both my brother (Ph.D., chemical engineering) and my son (mechanical engineering) play jazz guitar. 
  First, I agree that overly much had been made of hemisphericity and its supposed role in cultural as well as individual differences.  

  Second, I also suspect that pervasive regional and subcultural differences in thinking patterns are sometimes real and when they *are* real, are indeed loosely related to different ways of using the same cognitive talents present in all of us (that is, using the same human brain in different ways).  I don't see these two views as contradictory once we grasp the differences in logical levels between brain function and actually using the mind.  

  The differences in the way the cerebral hemispheres work probably does plays a role in pervasive differences in thinking patterns, although the notion of "drawing on one side of the brain" is surely simplistic and isn't a very practical or accurate way of thinking about the implications of this. It implies that using your brain differently is like flexing your left arm rather than your right arm, which confuses function with neuroanatomy.  The fact that some function of the brain has some relationship with a particular part of the brain doesn't tell us as much as one might think because we generally think of it as a mechanical relationship, whereas brain function is a partly a result of organized massive intercommunication, not just mechanical relationships between component parts.  Also, the mind in action is structured partly by how it is used rather than (just) how it is wired.  

  As a result, there are a couple of different ideas here that are usually confused together: (1) differences in cognitive patterns that vary in different environments (e.g. "cultural" thinking differences), and (2) cognitive differences related to hemisphericity, the specialization of the human cerebral cortex.  

  In "Geography of Thought," Richard Nisbett does an early but plausible analysis of the factors that lead to pervasive culture thinking differences of the sort we used to associate with being "right" vs. "left" brained.  His thesis: the organization of human groups, partly a result of ecological condtions, helps determine the way human beings form and process basic concepts and even influences basic perception in some ways.  His thesis is tested in the laboratory and applied to speculations about geographical and cultural differences. 

  Does this link back to the hemispheres?  Possibly to some degree.  Bob Ornstein, an early adopter of the strong hemisphericity thesis and later skeptic, finally gives a moderate account in "The Right Mind: Making Sense of the Hemispheres."  Essentially he concludes that while the earlier interpretations of "creative" or "mystical" right brains and "logical" left brains were not supported in fact (nor even the idea that the right side is "mute"), it appears to be true that there is a profound evolutionary and developmental division where essentially the brain specializes into providing the context or big picture, and keeping track of the details.  

  It isn't hard to see that keeping track of details would play a large role in Nisbett's Western cultural model of thinking, which emphasizes the properties of individual objects, and that providing context would play a large role in processing complex systemic relationships of the sort that characterize Nisbett's Asian model of thinking.

  Perhaps Nisbett's differences couldn't be manifested without Ornstein's differences, so we could rightly say they are linked in some way.  On the other hand I think it would be wildly inaccurate to say that they are simply the same thing.
  Ornstein, Robert, (1998).  "The Right Mind: Making Sense of the Hemispheres."  Harvest Books.

  Nisbett, Richard (2003). "The Geography of Thought: How Asians and Westerners Think Differently and Why."   Free Press.

  kind regards,



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