The Left-Brain, Right-Brain Myth

human brain

New research indicates that left-brain and right-brain dominance is a myth. (Photo credit: Photodisc/Getty Images)

You have probably heard that if you are creative, imaginative, and artistic, you are right-brain dominant, and if you are analytical, logical, and well-organized, you are left-brain dominant. However, recent research by scientists at the University of Utah indicates that the left-brain/right-brain dichotomy is nothing more than a myth.

The truth of the matter is that your brain is not made up of two completely separate hemispheres. Instead the left and right hemispheres are connected by a band of neural fibers called the corpus callosum. The concept of left-brain/right-brain dominance rose in popularity in the 1960s through the Nobel Prize-winning research of Dr. Roger Sperry. Sperry studied the brains of epileptic patients who had their corpus callosums cut as a treatment for their disorder. In studying their brains, Sperry was able to determine which parts or sides of the brain were involved in activities such as language, math, drawing, and other functions. Left-brain/right-brain dominance gained traction in popular psychology as an interesting way to categorize personality traits, though such a notion never caught on with the mainstream neuroscience community.

Dr. Jeff Anderson, director of the fMRI Neurosurgical Mapping Service at the University of Utah, and his colleagues conducted a two-year study of brain function. Over the two-year period, the researchers studied the brain functions of 1,011 participants between the ages of 7 and 29. The scientists used brain scans from the International Neuroimaging Data-Sharing Initiative, or INDI. These scans were taken during a functional MRI analysis. During this type of analysis, a participant lies in an fMRI scanner for a period of 5 to 10 minutes while the participant’s resting brain activity is analyzed.

In the study, the scientists looked at activity in 7,000 brain regions and analyzed neural connections within and between these regions. While the researchers saw some areas of heavy neural traffic in particular regions of the brain, on average, both sides of the brain were equal in neural networks and connectivity. In other words, the scientists did not see left-brain or right-brain dominance in any of the study participants.

“It’s absolutely true that some brain functions occur in one or the other side of the brain,” Dr. Anderson said in a statement about the research. “Language tends to be on the left, attention more on the right. But people don’t tend to have a strong left- or right-sided brain network. It seems to be determined more connection by connection.”

According to Jared Nielsen, a University of Utah neuroscience graduate research assistant who led the study, the results are groundbreaking.

“Everyone should understand the personality types associated with the terminology ‘left-brained’ and ‘right-brained’ and how they relate to him or her personally.” Nielsen said in a statement about the study. “However, 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. It may be that personality types have nothing to do with one hemisphere being more active, stronger, or more connected.”

The research, titled “An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging,” was published in the August 2013 edition of the open-access, peer-reviewed journal PLOS ONE.

More to Explore
An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging
Left Brain vs. Right: It’s a Myth, Science Finds
Despite What You’ve Been Told, You Aren’t ‘Left-brained’ or ‘Right-brained’
The Truth About the Left Brain / Right Brain Relationship
Researchers Debunk Myth of ‘Right-brained’ and ‘Left-brained’ Personality Traits

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