Although centuries have passed, these traits are still detectable in the modern world, changing with the environments where people live. Since we are social beings, affecting each other without even realizing it, people in developed areas of the world display a prevalence of RHS domination. The reverse is common in developing regions of the world and places with extreme climate. Many of the ancient tribes of the Arctic were LHS-dominant cultures.
These traits are hardly unique to people, for that matter. Studies of birds like the Chickadee are consistent with these results. Chickadees indigenous to Canada have LHS dominance compared to their relatives from Texas. One experiment had the populations change places, and the action-reliant Texans soon became prevalent in the Yukon.
When saying that either the LHS or RHS becomes dominant, bear in mind that both hemispheres of the brain continue to function, but during interactions, one side gradually becomes dominant, drowning the other out. In the moment right before we act, but have already decided to do so, we are changing the state of our brains, shifting the weight balanced by each hemisphere.
Whether we act or not, we impact the way in which one hemisphere can mute out the other. At the same time, the less effective, restricted hemisphere learns how to give off more excitatory signals with more frequency for next time. If you choose to splurge on dessert, your LHS has effectively inhibited the RHS and altered the power dynamic, making the LHS just slightly more dominant than the submissive RHS. If you choose to avoid the calories, then the reverse happens.
Over one’s lifetime, these decisions in an ever-changing anatomy, along with one’s own environment, will determine both the structure and plasticity of the individual’s brain. If you happen to think of your life as dull and suburban, chances are that your LHS contains fewer distinct neural networks than the RHS. In individuals that are violent offenders, the LHS appears much more distinct and pronounced than their RHS.
However, veteran gang members have displayed some of the most visible symmetry between both hemispheres of the brain. Although these individuals show an amazing propensity to behave in extremely risky ways — the ruthlessness needed for doing business with dangerous associates, or just for surviving in high-stress environments like prison — they also prove to be just as capable of inhibiting themselves from acting out.
Following The Synaptic Trail
To more fully understand the operations between the cerebral hemispheres, one must follow the path of the neural networks around them. Our association of the LHS with action and emotion is because of its connectivity to specialized parts in the brain across both hemispheres that play a role in those behaviors.
Most significant are LHS connections to both the brain’s insular cortex (a key part of consciousness and self-awareness — the reason we took that Facebook quiz in the first place) and the amygdala, which is critical in decision-making and memory-manufacturing.
Our association of the RHS with inaction and calculation is because of its neural networks that attach to the anterior cingulate (likewise involved in decision-making, but also error detection and reward anticipation — allowing you to see the long-term benefits of putting off the dessert) as well as the orbitofrontal and prefrontal cortices (which signal possibilities of punishment and reward with each decision).
Describing oneself as left- or right-brained hardly seems to give an accurate portrait of ourselves at all. The plasticity of our brains is constantly at work, causing dozens of changes at every moment. Involuntarily, information is passing back and forth between the hemispheres. Even patients suffering damage to the LHS have been able to form neural connections in the RHS to carry out the tasks traditionally associated with the LHS.
Those with RHS damage show a high degree of functionality in motor skills after new neural connections develop in the LHS. Despite grievous injuries, these shifts continue to occur, even on the level of neurons, which gather on each side when signaled by the RHS. This shift in the neurons’ functioning is actually similar to what occurs in people who lose their sense of sight or hearing, and when specialized neurons serve to boost the other senses to compensate for the loss.
This article was originally published in Brain World Magazine’s Summer 2016 issue.
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