You are not Left Brained nor Right Brained

Super fact 134 : The idea that people have a dominant “left brain” or “right brain” that dictates their personality is a popular myth. Brain imaging studies show that people do not have a dominant hemisphere.

A left brain in orange and right brain in blue. The entire brain is surrounded by what looks like electricity. | You are not Left Brained nor Right Brained
Shutterstock asset id: 2483871211 by Shutterstock AI

The left and right sides of the brain do tend to specialize in different tasks. For example, language tends to be on the left, and attention more on the right. Brain images studies show that we do not have a dominant hemisphere. Both halves of the brain work together and are used equally in most activities. You can read more about the topic here, and here, or here.

Four Minute Video on Left Brain versus Right Brain

The YouTube video below is 4 minutes long, but it presents a good overview of left brain versus right brain myth.

How did the right brain versus left brain myth get started ?

That the brain is divided into a left side and a right side has been known since ancient times. In the 1860’s it was discovered that speech was based predominantly in the left hemisphere of the brain. In the 1960’s Psychobiologist Roger Sperry studied “split-brain” patients who had their corpus callosum (the nerve bundle connecting the two halves) severed to treat epilepsy. Their neuroscience research seemed to show that one side of the brain tends to be more dominant in each person. Popular culture took these findings out of context and the right brain versus left brain myth took hold.

A rotating transparent skull with a colored brain inside.
The human brain is divided into two hemispheres–left and right. Scientists continue to explore how some cognitive functions tend to be dominated by one side or the other; that is, how they are lateralized. Purple is the Right cerebral hemisphere. Blue is the Left cerebral hemisphere. Polygon data were generated by Database Center for Life Science (DBCLS), CC BY-SA 2.1 JP <https://creativecommons.org/licenses/by-sa/2.1/jp/deed.en&gt;, via Wikimedia Commons. The gif is taken from this link.

Later research showed that the human brain does not favor one side over the other and that one side is not more dominant then the other, unless it is damaged. The two sides of the brain work in concert. You can read more about the topic here.

A related fascinating fact is that the human brain contains about 100 billion neurons and 100 trillion connections. That is 100 trillion parameters to use Artificial Intelligence speech. Which should be compared to the 175 billion (not trillion) parameters in ChatGPT 3.5, and one trillion in ChatGPT 4.0. Well AI neurons and connections/weights and those in the brain are not directly comparable. Another related interesting myth is that we only use 10% of our brain. We use our entire brain.

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Author: thomasstigwikman

My name is Thomas Wikman. I am a software/robotics engineer with a background in physics. I am currently retired. I took early retirement. I am a dog lover, and especially a Leonberger lover, a home brewer, craft beer enthusiast, I’m learning French, and I am an avid reader. I live in Dallas, Texas, but I am originally from Sweden. I am married to Claudia, and we have three children. I have two blogs. The first feature the crazy adventures of our Leonberger Le Bronco von der Löwenhöhle as well as information on Leonbergers. The second blog, superfactful, feature information and facts I think are very interesting. With this blog I would like to create a list of facts that are accepted as true among the experts of the field and yet disputed amongst the public or highly surprising. These facts are special and in lieu of a better word I call them super-facts.

61 thoughts on “You are not Left Brained nor Right Brained”

  2. I’ve heard both of these; the 10% thing went by the wayside a long time ago. The left/right dominance thing stayed longer, however. Being left-handed, I always thought I was one of the few in my right mind. But seriously, this myth has a lot of staying power.

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    1. Thank you so much Denise. Yes I believed the left brain right brain myth for a long time. I was convinced I was left brained. However, as it turned out, it was not that simple. Left handed or right handed, you are still one of the few in your right mind.

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  4. I totally bought into the myth and considered myself more right-brained, especially since I did not excel in math and sciences at school. 🫣 Thanks for clearing that up! As for the 10% myth, that didn’t resonate. Fascinating info about ChatGPT!

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    1. Thank you so much Debbie. I bought into the myth as well, but I was convinced I was left-brained. Math and physics was easy for me but I sucked at art. ChatGPT and other LLMs are far from human level intelligence and capabilties even though it may not look that way. However, thanks to Moore’s law the LLMs and other AI will keep getting better and better and trillions of times more powerful. What then?

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    1. Yes I knew you were both analytical and very creative with art, poems, writing, etc. It is pretty obvious. Some people just have it all. I’ve read that the number of connections have something to do with IQ but that brain size or number of neurons less so. However, I have to read more about that.

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            1. I am not sure but it might be going that way. I’ve read somewhere that some AI scientists were betting that a full brain simulation (copying all brain functionality and beyond) could happen as early as 2045, assuming Moore’s law keep holding. There are some that say it will take much longer and others who say it will never happen. However, we need to prepare for the possibility. We don’t want a nasty surprise like SkyNet in the Terminator.

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    1. You are right Java Bean, it may seem circular, but it really isn’t. The Universe is examining and analysing itself, and it is possible. We humans have big brains but you dogs use yours very effectively. You are very smart.

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  9. I remember reading about split-brain studies for our psych classes. My favorite one was where they showed people with severed corpus callosa different pictures and asked them to describe what they saw, and when they showed a female patient a racy picture in one eye she just kind of started to smile but couldn’t say why, and when they asked her to explain she just said something like “Oh, that funny machine of yours!”

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  10. Thank you for clearing this up so well. Popular culture and mainstream media tend to like division and conflict, and though the myth seemed to be reinforced in my early 80s college psych classes due to the amount of time we spent on split brain research, I’ve always known I was not right or left brain dominant. Our brains are way more adaptive than that.

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    1. Yes you are right JoAnna, and it took a few decades until the 2010’s before the scientists began to clear up the right-brain left-brain over simplification. Whether the researchers in the 1960’s were right or with all theur conclusions from their split brain research, they still moved science forward.

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  16. Fascinating post, Thomas! It’s amazing how deeply the “left-brained versus right-brained” idea became embedded in popular culture. I especially enjoyed learning how the myth developed from real scientific discoveries that were later oversimplified. Another great reminder that the human brain is far more complex—and fascinating than the labels we give it. Excellent post!

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          1. Yeah, it’s getting more necessary too with mental health issues on the rise which is quite unfortunate. I always found psychology interesting, it’s the maths parts that made me decide not to major in it. I’m not good with statistics.

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            1. Oh yes statistics. I think I am pretty good with statistics, but the rest of psychology is harder for me. I would be a terrible psychologist. But like you say, mental health issues are on the rise so psychologists are needed.

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              1. I’m the opposite, I’m good at everything but the stats and biology parts of psychology. It’s funny how our brains can be so good at one thing and bad at something else. It’s like we all have a superpower and weaknesses.

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    1. So what the articles are saying is that differences in personality and thinking styles, as you give an example of, comes from life experiences, psychological categorization, etc., rather than a dominant brain hemisphere. Also even for traits such as being artistic or analytical, both sides work together. Also we humans tend to put personalities and traits into boxes that are too simplistic.

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  19. I’m only partly convinced. What about artistic abilities that seem to be inherited and often go with being left-handed (right-brained)? Could it be that family and life influences help certain characteristics to be stronger and then this is passed on to the next generation? I find it interesting (slightly off topic here) that quite often, people who find social interactions difficult also don’t swing their left arm as naturally when they walk as they do their right arm. (Right brain that governs the emotional/social aspects of life, doesn’t work as easily in governing the left side of the body, which it is supposed to do). People who are organized and mathematically inclined would be more likely to swing their right arm vigorously than an artistic right-brained person. This is all very generally speaking. What do you think?

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    1. That is OK it is good to ask questions. I have expertise in Artificial Intelligence, Physics, robotics, some in climate science and mathematics, but no expertise in neuroscience/psychology. I keep my super facts basic and verify with reputable sources in all fields and sometimes wikipedia and encyclopedia britannica (good-nuff sources). As you can see I add many of those links to the posts. I also get help from people who have expertise in those fields, to make sure I get it right. This is what Psychology today say about left-handedness and creativity “Left-Handedness and Creativity” Basically, No link between left-handedness and creativity was found. I can add that according to my settings you can put two links per comment. If you want to add more links you have make multiple comments.

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  20. I guess I can only judge by what I’ve seen, but it’s another thing to attach a cause for what I see, and I could be completely wrong. It could be just one coincidence after another. Thanks for your response. It’s interesting to hear other people’s points of view on these nebulous ideas.

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