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Monday, May 27, 2024

The civil war inside you

Most people understand, or at least loosely grasp the idea of our brains’ functions in everyday life. The brain regulates our heartbeat, our breathing, pain and emotional responses and contains the genetic blueprint for our personalities – the “nature” that determines how “nurture” is interpreted.

However, most people are completely unaware of our brains’ roles in shaping our society and culture. The brains’ left and right hemispheres are constantly interacting to shape our perceptions of, and interactions with, the world.

Scientists know that the left hemisphere controls the right half of the body, and the right hemisphere controls the left half. This cross wiring does not make understanding its functions any easier. Added to that is a bundle of neural fibers called the corpus callosum that bridges the gap between the two hemispheres.

Of course, the distinction between hemispheres is not as clear-cut as left vs. right. Clifford Saron is an associate research scientist at the UC Davis Center for Mind and Brain (CMB), and he believes that the media and popular science have drastically oversimplified the brain’s systems.

“Our culture is interested in pre-existing dichotomies,” said Saron. “Like the devil and angel on our shoulders … there exists an inappropriate romance with left vs. right hemisphere function.”  

He explained that this emphasis is due to research conducted on split-brained patients – patients who either had no corpus callosum or had their corpus callosums cut in order to fix severe epilepsy.

It could be argued that what makes us human is not our biology and genetics, but the cultural trademarks that unify us: music and language in particular. These emblems of humanity are the result of a continuing struggle for dominance between our left and right cerebral hemispheres. So far, the left hemisphere seems to have the upper hand, as demonstrated by the 90 to 93 percent of the population who are right-handed with left-brain dominance.

We can see the manifestations of this conflict every day in many languages. The French word for left, gauche, is the same as the word for bad, awkward and crude. In Italian, the word for left, mancino, denotes deceitfulness. In Anglo-Saxon, lyft meant worthless. In English, we have the phrase, “in his right mind,” to indicate sanity, “right-hand man” to indicate a trusted friend and the etymological origin of the word ambidextrous means “two right hands.” As popular science writer Carl Sagan said, “we have no bill of lefts.”

For Tamara Swaab, an associate professor of psychology here at UC Davis, the multilingual preference toward the right makes sense. According to Swaab, the right hemisphere is responsible for seeing the “big picture,” but it is the left hemisphere that is responsible for converting the associations made in the right hemisphere into written and spoken words.  

The separation of hemispheric function becomes unclear when music is involved, and is muddled even further depending on whether you are listening to, or creating music.

“People with more expertise in music use the left brain more than the right,” said Stephen Luck, a professor of psychology and director of the CMB here at UCD.

He said that this is because the left hemisphere is responsible for creating patterns.  

However, it is the right hemisphere that has been generally accepted as the source for music appreciation, and both hemispheres are required to differentiate pitch, tone and tempo. Since no one’s brain operates the same way, appreciation for music is as individual as the person listening to it.

The brain is the most complicated biological system known to man. Not even the most advanced computer systems can emulate the brain’s capabilities. Since the brain’s functions are an amalgamation of genetic “nature” and socialized “nurture,” it is likely that we will never be able to wrap our minds around the concept of the brain with any degree of certainty.

For neuroscientists, the puzzle of the mind is exciting. In Saron’s words, the complexity of the brain is “a total miracle to think about.” 

HUDSON LOFCHIE can be reached at science@theaggie.org. Follow him on Twitter @HudtacularSci.


  1. Nice explanation about an obviously complicated subject. What say you about right-handed people who have a predominance of left-handed friends?


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