Left Brain vs. Right: It's a Myth, Research Finds

by Christopher Wanjek | September 03, 2013 12:21pm ET

It's the foundation of myriad personality assessment tests, self-motivation books and team-building exercises – and it's all bunk.

Popular culture would have you believe that logical, methodical and analytical people are left-brain dominant, while thecreative and artistic typesare right-brain dominant. Trouble is, science never really supported this notion.

Now, scientists at the University of Utah have debunked the myth with an analysis of more than 1,000 brains. They found no evidence that people preferentially use theirleft 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.

A paper describing this study appeared in August in the journal PLOS ONE. [10 Things You Didn't Know About the Brain]

The preference to use one brain region more than others for certain functions, which scientists call lateralization, is indeed real, said lead author Dr. Jeff Anderson, director of the fMRI Neurosurgical Mapping Service at the University of Utah. For example, speech emanates from the left side of the brain for most right-handed people. This does not imply, though, that great writers or speakers use their left side of the brain more than the right, or that one side is richer in neurons.

There is a misconception that everything to do withbeing analyticalis confined to one side of the brain, and everything to do with being creative is confined to the opposite side, Anderson said. In fact, it is the connections among all brain regions that enable humans to engage in both creativity and analytical thinking.

"It is not the case that the left hemisphere is associated with logic or reasoning more than the right," Anderson told LiveScience. "Also, creativity is no more processed in the right hemisphere than the left."

Anderson's team examined brain scans of participants ages 7 to 29 while they were resting. They looked at activity in 7,000 brain regions, and examined neural connections within and between these regions. Although they saw pockets of heavy neural traffic in certain key regions, on average, bothsides of the brainwere essentially equal in their neural networks and connectivity.

"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," said Jared Nielsen, agraduatestudent and first author on the new study.

The myth of people being either "left-brained" or "right-brained" might have arisen from the Nobel Prize-winning research of Roger Sperry, which was done in the 1960s. Sperry studied patients withepilepsy, who were treated with a surgical procedure that cut the brain along a structure called the corpus callosum. Because the corpus callosum connects the two hemispheres of the brain, the left and right sides of these patients' brains could no longer communicate.

Sperry and other researchers, through a series of clever studies, determined which parts, or sides, of the brain were involved in language, math, drawing and other functions in these patients. But then popular-level psychology enthusiasts ran with this idea, creating the notion that personalities and other human attributes are determined by having one side of the brain dominate the other.

The neuroscience community never bought into this notion, Anderson said, and now we have evidence from more than 1,000 brain scans showing absolutely no signs of left or right dominance.

Anderson said he wasn't out to do some myth busting. His team's goal is to better understand brain lateralization to treat conditions such as Down syndrome, autism or schizophrenia, where the left and right hemispheres have atypical roles.

So, should you trash your app that tries to determine if you are a left-brain or right-brain thinker? Both sides of your brain, as well as neuroscientists, say yes.

Christopher Wanjek is the author of a new novel, "Hey, Einstein!", a comical nature-versus-nurture tale about raising clones of Albert Einstein in less-than-ideal settings. His column,Bad Medicine, appears regularly on LiveScience.

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1/24/2016 Public Affairs Blog Article 1/2 Researchers Debunk Myth of "Rightbrain" and "Leftbrain"Personality Traits bilateral motor render The orange shaded areas show parts of the brain in the left and right hemisphere responsible for moving this patient's hand. Motor function is organized such that the left side of the brain controls muscles in the right side of the body and vice versa. Aug 14, 2013 3:00 PM (SALT LAKE CITY)— Chances are, you’ve heard the label of being a “rightbrained” or “leftbrained” thinker. Logical, detailoriented and analytical? That’s leftbrained behavior. Creative, thoughtful and subjective? Your brain’s right side functions stronger —or so longheld assumptions suggest. But newly released research findings from University of Utah neuroscientists assert that there is no evidence within brain imaging that indicates some people are rightbrained or leftbrained. For years in popular culture, the terms leftbrained and rightbrained have come to refer to personality types, with an assumption that some people use the right side of their brain more, while some use the left side more. Following a twoyear study, University of Utah researchers have debunked that myth through identifying specific networks in the left and right brain that process lateralized functions. Lateralization of brain function means that there are certain mental processes that are mainly specialized to one of the brain’s left or right hemispheres. During the course of the study, researchers analyzed resting brain scans of 1,011 people between the ages of seven and 29. In each person, they studied functional lateralization of the brain measured for thousands of brain regions —finding no relationship that individuals preferentially use their left brain network or right brain network more often. “It’s absolutely true that some brain functions occur in one or the other side of the brain. Language tends to be on the left, attention more on the right. But people don’t tend to have a stronger left or rightsided brain network. It seems to be determined more connection by connection, ” said Jeff Anderson (http://healthcare.utah.edu/fad/mddetail.php? physicianID=u0281911#jeff%20anderson) , M.D., Ph.D., lead author of the study, which is formally titled “An Evaluation of the LeftBrain vs. RightBrain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging.” It is published in the journal PLOS ONE this month. Researchers obtained brain scans for the population they studied from a database called INDI, the International Neuroimaging DataSharing Initiative. The participants’ scans were taken during a functional connectivity MRI analysis, meaning a participant laid in a scanner for 5 to 10 minutes while their resting brain activity was analyzed. By viewing brain activity, scientists can correlate brain activity in one region of the brain compared to another. In the study, researchers broke up the brain into 7,000 regions and examined which regions of the brain were more lateralized. They looked for connections — or all of the possible combinations of brain regions — and added up the number of connections for each brain region that was left lateralized or rightlateralized. They discovered patterns in brain imaging for why a brain connection might be strongly left or rightlateralized, said Jared Nielsen, a graduate student in neuroscience who carried out the study as part of his coursework. “If you have a connection that is strongly left lateralized, it relates to other strongly lateralized connection only if both sets of connections have a brain region in common,” said Nielsen. Results of the study are groundbreaking, as they may change the way people think about the old rightbrain versus leftbrain theory, he said. “Everyone should understand the personality types associated with the terminology ‘leftbrained’ and ‘rightbrained’ and how they relate to him or her personally; however, we just don't see patterns where the whole leftbrain network is more connected or the whole rightbrain 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,” said Nielsen. 1/24/2016 Public Affairs Blog Article 2/2 # # # Media Contacts Melinda Rogers Communication Specialist , Of ice of Public Af airs Phone: 8015870986 Email: (mailto:) Visit our News Archive (../archive/index.php) for a complete list of previous News.