Left-brain Versus Right-brain Myth

The idea that people could be left-brained and right-brained is ubiquitous—there are 200 million results on Google, a best-selling book by Daniel Pink, a BuzzFeed quiz, even Oprah describes herself as a “right-brained” person. However, there is actually no such thing as right-brain or left-brain dominance. The human brain is divided into two hemispheres that are connected to each other by the corpus callosum. Depending on the task, there are only localizations where more of one hemisphere is activated than another. These hemispheres each have assigned tasks that control movement and receive stimuli from the opposite side of our body. In other words, the left hemisphere controls the right side of our body and also receives sensory inputs from the right side of our body. Our brain is highly interactive, and there is a much more complicated exchange than the myth implies its functions to be.

In a study conducted in 2016, 78.5% of the pre-service teachers who participated accepted the validity of hemispheric dominance even when there have been other recent studies that prove cerebral functions require the use of both hemispheres (Dundar & Gunduz, 2016). There is currently no evidence linking hemispheric dominance to learning; however, it is the second most believed neuromyth, only after learning styles (Dundar & Gunduz, 2016). Additionally, brain-based learning has influenced the way curriculum is developed (Society for Neuroscience, 2009) and teachers may unknowingly incorporate many other neuromyths in their pedagogy. The lack of neuroscientific expertise in many educational institutions can result in the adoption of “brain-based” learning methods, all while not realizing its pseudoscientific nature. In fact, people are more likely to believe in claims that have embedded marketing buzzwords such as “brain” and “neuroscience” (Lindell & Kidd, 2011).

The prevalence of this myth, especially in the education sector poses dangers. For one, students may be taught material in methods that are not actually effective. Since “right-brain/left-brain” teaching methods have not been validated, nor have supporting evidence (Bruer, 2002), it would then be completely erroneous to adopt a “right-brain/left-brain” teaching. The consumption of this belief can be restricting and limiting in thinking that people’s capabilities and personalities are predicted by a split-brain point of view. The internalization of this neuromyth could impact people’s sense of self-efficacy and may even be a cause for self-fulfilling prophecies (Bandura, 1994).

Origin of the Myth and Supporting Evidence

In the 1800s, pioneers Paul Broca and Carl Wernicke showed that language production and comprehension are governed by two distinct brain regions, which came to be known as Broca’s and Wernicke’s area. Broca and Wernicke’s study suggested that language is controlled by the left side of the brain. This finding became the foundation of Robert Lewis Stevenson’s “Dr. Jekyll and Mr. Hyde” in 1886. He explored the duality of human nature in his work by introducing the idea of a logical left brain in the character of Dr. Jekyll competing with an emotional right brain in the character of Mr. Hyde (Waters, 2017).

With the dawn of the twentieth century, the whole left-brain right-brain obsession went relatively quiet until the 1960s through Roger Sperry’s split-brain experiments that awarded him the Nobel Peace Prize in 1981. The original study that purported this myth was done on participants whose brain functions were not at all typical in the first place--its intended purpose was to find more about epilepsy (Lienhard, 2017). Much of the original work of Sperry, who discovered the functioning differences between left- and right-brain hemispheres remain valid, but have been extrapolated--the conclusions are taken to an extreme, creating misunderstanding in thinking that is unsupported by literature and spread by popular media: New York Times Sunday Magazine published an article in 1973 titled “We Are Left-Brained or Right-Brained” and Harvard Business Review published an article in 1976 titled “Planning on the Left Side and Managing on the Right.” When reputable agencies are spreading this myth under the guise of self-improvement, a new psychology theory emerges that ultimately buries the truth in misconceptions.

In relation, the “Interpreter Phenomenon” is a concept introduced by Sperry’s student, Michael Gazzaniga. While performing his initial experiments, Gazzaniga and his colleagues observed patients when left and right hemispheres could no longer communicate. They were shown an image within the right visual field that maps to the left-brain hemisphere and were able to give an explanation. However, when the image was presented to the left visual field, the patients were only able to point to objects similar to the image. Gazzaniga interpreted this by hypothesizing that even though the right brain could see the image, it needed the left brain to generate a verbal response, thus characterizing the left hemisphere as “inventive and interpreting,” compared with the “truthful, literal right brain” (Gazzaniga, 2015). This statement, without proper understanding of brain processes can easily be misinterpreted and oversimplified. Sperry (1984) himself warned the public: “…experimentally observed polarity in right-left cognitive style is an idea in general with which it is very easy to run wild…it is important to remember that the two hemispheres in the normal intact brain tend regularly to function closely together as a unit.”

To say that an individual is left brained or right brained is incredibly false, yet the results of Perry’s study and others have been misunderstood to link brain lateralization with individual personality traits, even the mental states of others. The oversimplification of a complex neuroscience process could just be a result of our human instinct to understand things that which we do not, characterizing ideas and embracing simplified narratives despite warnings. There is no perpetual tug-of-war within the brain—the hemispheres are systems and should be viewed as such.

Evidence Against the Myth

Brain scans show no evidence of sidedness, instead there was actually activity on both sides of brain, depending on the task (Nielsen, Zielinski, Ferguson, Lainhart & Anderson, 2013). This study looked at 3D pictures of over 1,000 people's brains and measured the activity of the left and right hemispheres, using an MRI scanner. Results showed that both sides of the brain are engaged in cognitive processes, supporting lack of selective simulation in brains (Lindell, 2011).

One of the most widely held beliefs within the left-brain vs right-brain myth is creativity being a “right-brain” process. Further perpetuated and one of the most popular ideas is that the right brain is the center of imagination and that “right-brained” people are more creative that their left-brained counterpart. This has been refuted as both sides of the brain are involved in tasks requiring creativity (Runco, 2004, p. 665). The “interpreter phenomenon” as previously discussed, shows that it is naïve to portray the left hemisphere as incapable of creativity especially when logical tasks require creativity and creativity can also be rooted in logical reasoning even when people in creative careers show greater interaction in both sides of brain than those in non-creative professions (Gibson, Folley, & Park, 2009).

Brain lateralization is a multifaceted and ongoing process by which differing regions of the brain “specializing” the functioning of specific behaviors and cognitive skills. Indeed, the brain does have two hemispheres, but they have a complex working relationship and always operate with other areas of the brain (Noggle & Hall, 2011). It is important to note that laterization has no link to personality traits. Hence, no one is fully right-brained or left-brained (Sperry, 1961). Laterized functions in the healthy brain, such as language, can even be rewired into the other hemisphere, especially if the patient is very young. Increased laterization and plasticity is seen both before a child develops the activity and even after the function has begun to develop (Ressel, Wilke, Lidzba, Lutzenberger, & Krägeloh‐Mann, 2008) and can go on to live normal lives. Children with brain damage to their left hemisphere are able to continue language development and damage is undetectable by age 7 suggesting that even when one side is not working correctly, the other side will “take over” tasks to achieve cognitive processes as a unified system (Lindell, 2011; Reilly, Bellugi, & Wulfeck, 2004).

The simplicity that tasks are dominated by one side of the brain is a notion unsupported by science—even the study that was the basis of this popular lore did not necessarily apply to normal functioning brains. There are two hemispheres that each play critical roles in executing tasks; one side of the brain isn’t more creative, nor more logical, nor more analytical—some of these functions may be localized in one hemisphere, but their overall function is not reliant on solely one hemisphere because the hemispheres are not isolated from one another. The classification of brain functions in simple oversimplified dichotomies (“left-brain vs. right-brain”) is the reason this myth exists, one that largely ignores the intimate working relationship of a system that is the human brain.

References

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16. Waters, E. (2017). Waters, Elizabeth: The left brain vs. right brain myth. [Video file]. Retrieved from https://ed.ted.com/lessons/the-left-brain-vs-right-brain-myth-elizabeth waters#discussion