Science

You are not Controlled by Your Right-Brain or Your Left-Brain

Why this modern myth persists in spite of scientific evidence disproving its applicability

You are not Controlled by Your Right-Brain or Your Left-Brain July 25, 2017Leave a comment

Myths, legends, fairy tales, things you hear repeated on forums or shared across Facebook that, on the face, seem plausible but upon examination disintegrate in the light of rationality fill our daily lives. Some things we accept at face value because why not, eh? One of those common social myths is that of how some people are predisposed to certain talents because of the dominance of one side of the brain over the other. The left hemisphere of the human brain corresponds to logical thought and mathematics while the right hemisphere of the brain is tied to creativity and aesthetic…at least, that’s what you have heard, right?

At some point or another everyone will encounter this or a variation on this misconception of the the brain’s function. This division of the brain’s hemispheres and the subsequent erroneous functionality placed upon each is an over 200 year old myth that has persisted in popular parlance because of its deceivingly simplistic explanation and the human desire to divide objects into pairs of opposites. According to this Ted Ed talk, the incorrect notion derives from the 1800’s and a discovery by German neurologist and psychiatrist Carl Wernicke in 1874 in which he theorized about a connection, “between the left posterior section of the superior temporal gyrus and the reflexive mimicking of words and their syllables that associated the sensory and motor images of spoken words.” Because of Wernicke’s work with patients suffering from aphasia, or loss of the ability to speak, Wernicke’s theory became associated with a broader conception of the right side and the left side of the brain as controlling creativity versus logic and language. There is even an region of the brain named after him, called Wernicke’s area.

This social myth was further popularized by Scottish author Robert Louis Stevenson with the publication in 1886 of his Gothic novella Strange Case of Dr. Jekyl and Mr. Hyde. In this book, its content considered shocking for its time, the logical Dr. Jekyl is ruined by the chaotic (and completely opposite in disposition) Mr. Hyde. It is implied that this dichotomy lurks within every single person. The author may have found inspiration for his novella during his experience in the criminal case of his friend, Edinburgh’s Eugene Chantrelle who was convicted of the poisoning of his wife and several others, a trial at which Stevenson was present throughout. The disparate actions of the apparently calm and composed Chantrelle, who was a well-known Edinburgh French teacher, with the murderer that lurked beneath that facade inspired the idea of an inherent division in the persona of every human.

This idea became popular during a time when scientific progress was becoming a topic of popular discussion and was conflated with the very clear division of the brain into right and left hemispheres as shown in textbooks of anatomy. Writing for Live Science, Christopher Wanjek cites a University of Utah study that, “debunked the myth with an analysis of more than 1,000 brains. They found no evidence that people preferentially use their left or right brain. All of the study participants — and no doubt the scientists — were using their entire brain equally, throughout the course of the experiment.” The University of Utah’s team of scientists examined subjects from a range of ages of and backgrounds and found that during their directed tasks that each side of the brain operated in concert with the other, no one side ever dominating the other or, as graduate student Jared Nielsen summarized “We just don’t see patterns where the whole left-brain network is more connected, or the whole right-brain network is more connected in some people.”

Live Science’s Christopher Wanjek speculates in his article “Left Brain vs. Right: It’s a Myth, Research Finds,” that there may be a more modern origin for the dichotomy between left and right brain hemispheres found in the work of Nobel Prize winner Roger Sperry who studied patients with epilepsy in the 1960’s. Roger Sperry’s specialty in split-brain studies was facilitated by a medical procedure that separated the region connecting each hemisphere of the brain, the corpus callosum, on patients suffering from severe epilepsy. When the corpus callosum is cut and the connection between the left and right hemispheres of a brain is severed, an epileptic seizure, which normally begins on one side of the brain and travels to the other, can no longer do so which prevents seizures from occurring. Sperry’s experiments moved on to cats where he cut the connection between the left and right eyes in cats and also severed their corpus callosum. The results of these experiments led him to theorize that the two hemispheres of the brain function separately when not connected by the corpus callosum.

Sperry’s experiments eventually involved split-brain patients and tested the patients’ language abilities, motor skills, and eyesight. The results of these experiments lead to his theory that, “Indeed a conscious system in its own right, perceiving, thinking, remembering, reasoning, willing, and emoting, all at a characteristically human level, and . . . both the left and the right hemisphere may be conscious simultaneously in different, even in mutually conflicting, mental experiences that run along in parallel.” Wanjek’s estimation is a little more forgiving (and grounded in science) than the Ted Ed hypothesis about the origin of the left-brain/right-brain division but it cannot explain the persistence of this idea in popular culture. Finding the origins of the myth are not as interesting as examining as its ability to survive and morph, from a seemingly pseudo-romantic understanding of the mind as presented by the Stevenson novella to the coldly scientific experiments of Roger Sperry, the idea that people are inherently dominated by one side of the brain or the other continues to hold weight in common parlance.

Christian Jarrett, writing for Psychology Today, calls the left-brain/right-brain division a metaphor and one that should be challenged. Jarrett calls the idea seductive in its simplicity and cites the countless self-help professionals that claim to help people tap into one hemisphere or the other to unleash their creative or rational potential. While it might be appealing to label each hemisphere of the brain with its own discrete set of functions, this does not, “…note that the kind of tasks that engage one hemisphere more than the other don’t always map neatly onto the kind of categories that we find useful to talk about in our everyday lives. Let’s take the example of creativity. We may find it a useful shorthand to divide tasks up into those that are creative and those that are repetitive. But the reality of course is more complex. There are many ways to be creative.” In an article for The Guardian, Amy Novotny does not hold back, proclaiming “Despite what you’ve been told, you aren’t ‘left-brained’ or ‘right-brained’.” Like Christian Jarrett of Psychology Today, Amy Novotny ascribes a certain responsibility for the persistence of this scientifically inaccurate understanding of the brain’s function with the explosion of self-help books and experts who promise their followers they will help them tap into these talents hidden within each side of their brain.

Popular psychologists are likely to blame for the ascription of personality traits and labels to each hemisphere of the brain, using the scientific studies of Sperry and his graduate student assistance Michael Gazzaniga to justify their assertions. In a sociological aside, Amy Novotny notes that the left-brain/right-brain divide may extend beyond metaphor and into social structure and the human need to classify and compartmentalize the surrounding environment. Citing the popular personality exam, the Myers Briggs test – a battery of questions aimed at unearthing a person’s true disposition within a set framework of predetermined personalities – Amy Novotny says: “..the left-brained/right-brained thinker theory provides us with an explanation for why we are the way we are, and offers insights into where we fit into the world. It’s also a great conversation starter – and if used as a novelty, or a way to strengthen the “weaker half” of your brain, the myth is pretty harmless.” Though, like the Myers Briggs test there is little scientific evidence to support it, the metaphor only becomes insidious when it becomes a self-fulfilling prophecy, or, as Amy Novotny theorizes, when you tell a child they will not be good at certain things because of a certain predisposition to one side of the brain or the other then a parent or teacher unfairly inhibits a child’s development using the unscientific inferences without grounding in testing or applicable theory.

In this way, the left-brain/right-brain metaphor presents society with a unique challenge, and that is the need to discard a seemingly innocuous myth because of its potential to dampen someone’s belief in their own abilities. Telling someone to tap into their right brain to become a better painter is of no scientific merit and offers encouragement far inferior to simply telling someone to give it a try and see what practice can do. The persistence may have an evolutionary role not imagined by psychologists in that it helps humans quickly compartmentalize others and develop their talents in that area to their maximum potential. In another jab at pop psychology, the notion that an individual can be all he or she can be is a thoroughly modern one and would not have worked in the tribal societies within which much of humanity has existed for much of its history as a species.

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