Right brain/left brain, right?

Robert H. Shmerling, MD
Robert H. Shmerling, MD, Faculty Editor, Harvard Health Publications

Follow me on Twitter @RobShmerling

If you’re like me, you learned that about 90% of people are right-handed and much of the reason is genetic. And that’s true, although it remains a mystery why our genetic evolution led to so many more righties than lefties).

But for certain tasks, handedness can be “overcome.” For example, right-handed kids learning to play tennis, golf, or baseball can become successful hitting from “the other side.” It may be more a matter of how they are taught and what gets reinforced than about a hard-wired preference for one hand or the other.

According to new research, the idea of people being “left-brained” or “right-brained” may also be less fixed than we’d thought.

Recognize yourself?

According to conventional wisdom, people tend to have a personality, thinking style, or way of doing things that is either right-brained or left-brained.

Those who are right-brained are supposed to be intuitive and creative free thinkers. They are “qualitative,” big-picture thinkers who experience the world in terms that are descriptive or subjective. For example, “The skies are gray and menacing; I wonder if it’s going to rain?”

Meanwhile, left-brained people tend to be more quantitative and analytical. They pay attention to details and are ruled by logic. Their view of the weather is more likely, “The forecast said there was only a 30% chance of rain but those cumulonimbus clouds will probably bring thunder as well as rain.”

A popular book first published in 1979, Drawing on the Right Side of the Brain, extends this concept. It suggests that regardless of how your brain is wired, getting in touch with your “right brain” will help you see — and draw — things differently.

These notions of “left and right brain-ness” are widespread and widely accepted. But they may also be wrong.

Location matters

There is truth to the idea that some brain functions reside more on one side of the brain than the other. We know this in part from what is lost when a stroke affects a particular part of the brain. For example, it has long been thought that, in most people, control of language resides in the left side of the brain. And there are areas of the right half the brain that control movement of the left arm and leg (and vice versa). Damage to the front part of the brain is linked with reduced motivation, difficulty planning, and impaired creativity. Meanwhile, the back of the brain (the occipital cortex) integrates visual information from the eye. Damage to this area can cause partial or complete blindness. These are just a few examples of how certain parts of the brain appear responsible for specific functions. So, location does matter.

But for more individual personality traits, such as creativity or a tendency toward the rational rather than the intuitive, there has been little or no evidence supporting a residence in one area of the brain. In fact, if you performed a CT scan, MRI scan, or even an autopsy on the brain of a mathematician and compared it to the brain of an artist, it’s unlikely you’d find much difference. And if you did the same for 1,000 mathematicians and artists, it’s unlikely that any clear pattern of difference in brain structure would emerge.

The right-brain/left brain myth?

So, is the idea of “thinking with the left side of your brain” a myth? Maybe. But, the lack of proof does not prove the opposite. For people living thousands of years ago, an inability to prove the earth was round did not prove the earth was flat!

But, the evidence discounting the left/right brain concept is accumulating. According to a 2013 study from the University of Utah, brain scans demonstrate that activity is similar on both sides of the brain regardless of one’s personality.

They looked at the brain scans of more than 1,000 young people between the ages of 7 and 29 and divided different areas of the brain into 7,000 regions to determine whether one side of the brain was more active or connected than the other side. No evidence of “sidedness” was found. The authors concluded that the notion of some people being more left-brained or right-brained is more a figure of speech than an anatomically accurate description.

The bottom line

If you’ve always thought of yourself as a “numbers person” or a creative sort, this research doesn’t change anything. But it’s probably inaccurate to link these traits to one side of your brain. We still don’t know a lot about what determines individual personality; but it seems unlikely that it’s the dominance of one side of the brain or the other that matters.

Related Information: Your Creative Brain

Comments:

  1. Carolyn F. Sur

    As a “both-sider,” this information was most helpful. I am easily more creative than average, taught math in secondary and college level for 25 years, and find directions when driving my greatest challenge. Earning a doctorate in historical theology was much easier for me than a masters in mathematics at the same university. I remain a “puzzlement” to those who claim to know me. Carolyn

  2. Frederick W.H Collins

    One thing I see is that Arabic is written right to left. Were the inventors of written Arabic left handed?

  3. Richard Reiling

    Just an addendum: As a medical student at Harvard, our genetics faculty was convinced that handedness was defined by a typical dominant-recessive distribution. This would indicate that about 25% of our class would be left-handed. However, only about 12% was left handed – so much for a genetic explanation!

  4. Richard Reiling

    As a left hander, this concept has always intrigued me. Clearly, I used my left hand preferentially from birth but many influences in my life changed my pattern of activity. Probably the first was the effect of my grade school teachers who tried to convert, at least my handwriting, to my right hand. Fortunately my mother stopped that but did get to to straighten out my left handing when writing.
    I have developed a right/left ‘dyslexia’ in that I tend to go the other way than right or left when thinking or told to do so. It is frustrating to this day and I have not been able to change. It did cause a few problems when I was a pilot of my own airplane; but, not as a surgeon!
    What was difficult in my career was the overwhelming emphasis on right-handedness in the operating room. Even the majority of instruments are designed specifically for right handers, to wit, scissors, needle holders and ratcheted clamps! The pejorative terms used have been annoying, especially when a nurse would respond, “oh, you use the wrong hand!”
    So to this issue, I can’t say what side of the brain I am using and it really doesn’t make a difference. I can say after a right sided, frontal lobe CVA, that muscle control of my left arm is the prime issue, not speech, etc.

  5. sharon willson

    Ridiculous. We deal with right brain/ left brain stroke survivors which depict a definite difference in what they can do or not do. ie: numbers, speech, singing, behaviours.. “A DEFINITE DIFFERENCE”

    • Rob Shmerling

      Of course certain parts of the brain control certain functions, as noted in the “Location Matters” section – and yes, this is quite clear in stroke patients and others with brain disease; but this piece is describing brain sidedness and less finite functions such as personality types, “being good at numbers” vs. being intuitive and so on.

  6. Lokesh Punj

    Still a vast majority of people are unaware that growth of neurons forming human brain starts early and is almost complete by the age of 4 to 5 years and the basic hard wiring or circuitry connections patterns get developed in early childhood and neurons not used or sparingly used get decomposed. Parenting with good coaching and focus on ability of parents and teachers for a healthier upbringing and use of brain by children is the most important part. Good that lefties are at no major disadvantage except writing of scripts can be left to right only….
    Do we use our brain to its full capacity? No . We do not use even the skills and knowledge gathered to even a quarter of the whole!

  7. Margaret Bourdette

    The amazing thing is that when I feel most in tune with God,
    my brain feels clear and light. I hope there can be more studies done with people who use prayer to become more inspired.

    I am amazed at how the Lord can forgive me and clear my brain, even after it has felt muddled or unclear.

    Thanks,
    Margaret in San Diego, CA

  8. Papp Sandor David

    Robert is wrong.
    Handedness is strictly hard-wired.
    One can be forced to use the “other hand”, but it will be a lifetime hurt.
    Also, it is everyday experience, that left-handed people have different menthality than right-handed ones.
    Not better, just different.
    Nobody can deny it, so don’t question it.
    It can be a hypothesis, that it comes from the “brainness”.
    But even if the science cannot prove it, you should accept that there is a main difference between righ-handed and left-handed people.
    Maybe, a right-handed one can even “draw with right brain”.
    Congratulations, well done.
    However, the difference still exists between right-handed and left-handed people.

  9. Leticia Sison

    What about ambidextrous individual like me? I can use both hands in many ways though each hand is more adept in some functions than the other. I could not remember how I learned to write with my right hand but I can also write with my left if I need to.When I get tired using my left I can also switch to my right without any problems ( ex. slicing, ironing, holding, sweeping).
    When I became conscious of my being ambidextrous , I began using my right hand as I learned new skills ( knitting, giving injections).
    Is there any study about ambidextrous individuals? What percentage of the population and how many are indeed gifted in both brain functions?

    • julie

      letecia, you bring up an interesting point about being ambidextrous. I too am ambidextrous, but not to the full extent as you – my left/right handedness is completely random – i write left handed, brush my teeth left handed, but i use scissors with my right hand (I wouldn’t be able to cut something with my left hand to save my life). As a child in school I didn’t want the left handed scissors as they were incredibly awkward for me. I can write on a chalk board with my right hand, but prefer my left. I can say that I utilize my right hand/arm for most gross motor skills (tennis, golf). I would guess it’s mostly gross versus fine, but i can’t say conclusively.
      i too would be interested in further research findings on this subject, because in truth, i’m about the most random mix of dichotomous characteristics one could find: i’m very black and white and analytical….but i lack superior math skills (or desire) because i’m riddled with ADD and fly by the seat of my pants in most scenarios. Most everyone thinks I’m highly organized, but i’m a flurry of chaos inside and out, and I always get the job done in superior fashion (but never remember how i did it two days later) – I can be overwhelmingly creative and whimsical, but it’s not a constant – as i tend (more comfortable) toward the logical path most often, and thinking outside of the box isn’t always my forte’ yet often times the most “out of the box” answer is ridiculously obvious to me when others can’t see it.
      So, I’ve never related to the “left/right brain” concept because of my mixed bag of traits. While I tend to believe the findings in the article, ” lack of proof doesn’t prove the opposite.”

      • Stephannie Bartos

        I loved both of these stories. The short version of my story is that I can draw and was always pretty good at math. I attribute both of these to parents that had time to spend with me in the years before I went to school. And they did so until I was 5– school started later in those years than it does now, and think I may have been quite different without that early boost in somewhat opposing talents.

  10. Robert Haile

    At age 66 my right shoulder rotator cuff was severely injured in a surfing accident. There was too much damage for surgery to be effective but with rehabilitation, I could use both arms to paddle for surfing. However, a lifetime sport, tennis, was out of the question. I decided to try with my left hand and with a lot of practice and patience, especially by my wife, I can now play almost as well with my left hand which is remarkable to me now age 68. I also grew up in an extremely alcoholic and dysfunctional family developing some nasty personal traits. This was aggravated by a ruptured right MCA aneurysm with a significant right brain insult, at age 28, causing some left sided weakness, pathfinding difficulties, and naming difficulties. I was in the middle of medical school and after 2 brain surgeries took a year off classes, but assisted in the anatomy lab and worked with a neurologist/physiatrist. When able, I began exercising, studying, and solving difficult mathematical problems in my head. Later, I began meditating and worked very hard on changing my very irritable personality. As my wife can attest, I changed remarkably over many years developing patience in addition to persistence, and becoming internally as well as externally calm. I did complete medical school and was first in the nation in my residency board exams, mentioned not to be self congratulating but to indicate how with hard work, even in the setting of a difficult childhood and a brain insult, one’s brain seems to have extensive plasticity as a young adult and even at an older age, but it does require very hard work.

  11. Ola Adewuya

    Right brain/left brain, right?
    Thank you for your enlightening discussion and information. I am a medical doctor trained in Nigeria, Switzerland and the United States. I am currently practicing in Nigeria where the issue of being Lesbian, Gay, Bisexual, Transsexual or Queer (LGBTQ) is a “Hot Button Issue!”. There is legislation against the act and recently a bunch of citizens were arrested for allegedly performing “Gay Acts” contrary to the law. This kind of action exists in some other African countries. After my exposure to Neuroscience in the US, and seeing and knowing personality changes that take place in people with brain damage after much common cerebrovascular disease in Nigeria, I came to the conclusion that, of course, certain areas of the brain, controls certain behaviors and specific actions. I personally believe that LGBTQ people are born that way. I respect all people of all creed and shades. In the country, people find it hard to understand that our brains may be different and that some people may have more, or fewer enhancements, rather biochemical, and less structural differences that influence their behaviors. There is evidence, that I have seen and studied myself, that the LGBTQ people are a variant of the mainstream and should be allowed to exist freely or protected. The question is: “has neuroscience conclusively, identified whether this group of people have a Right or Left sided brain dominance, or a biochemical difference in their brain activities that make them exist out of the mainstream of people? If so, I would appreciate more information and materials on this. In fact, there are many nuclear families here with children from the same parents, but one of them becomes an LGBTQ. The family cannot understand why and ascribes all kinds of non-scientific causes to the strange (to them) development. The person becomes miserable and lives a frustrated life. An estimated 60% of Nigerian families may be straight families consisting of a man a wife and children from both parents versus the likely 50% mixed marriage families that exist in the US, so the Nigerian family, where one person becomes an LGBTQ, may be an evidence of a genetic brain variant. I belong to the mainstream of the so called “straight people” but now confronted with the growing dilemma in the society and is neither an advocate or otherwise. Thank you.

  12. Ben Carter

    Whenever I see ‘University of Utah’ I discount the findings. Didn’t they give us tabletop fusion and similar frauds? But your objection seems obviously sound. Unless the subject is engaged in drawing or calculating, equal activity levels don’t mean anything.

  13. Joelle Morrison

    I am technically right-handed but do most things with my left hand. Brain-related or because my mother was a leftie and I do things the way she taught me? I don’t know. I believe I have mixed dominance; my proof is almost universal confusion when I meet a revolving door — which way to push? I also often see things differently when I’m deep in right-brain mode and it can be bewildering. If I remember, LOL, I use a breathing technique to shift to left-brain mode and bingo, I can function better. It’s simple, involves holding one nostril closed, breathe in and count to four with opposite nostril, then hold that nostril closed and exhale with the first. Continue for five or six shifts. It really works. Would love for someone to test that!

  14. Bruno Matellotto

    On the recently TV brain competition show I watch, I wonder how some people able to sort their memory like a ‘file manager’. They can remember something and then they placed it somewhere in ‘their brain’. When they want to use it, they’ll remember it. It was said to be ‘thinking with your both sides of your brain’. If thinking with either left side or right side do exist, how do they or we control it? Is it also possible to use your both sides of the brain at the same time?

  15. A Goldstein

    I guess it should follow that brain activity (i.e., electrical, blood flow or metabolism) indicates usage as in connecting with the outside world. But the brain is always metabolizing, receiving blood and producing some electrical activity. It is alive after all.

    Is it possible that esoteric brain activities like intuition, analytical thinking and creative thinking might occur at the baseline or ground state of the human brain? Perhaps our observational tools cannot measure everything of importance going on in the brain.

  16. Victor Arcega

    Researches to resolve the righty-lefty issue should include deeper studies on the unified and coordinated roles of corpus callosum, the occipital lobes, the thalamus and the handedness phenomenon. Otherwise, all that right-left question remain a mystifying anomaly. One such example of this anomaly is me. I am writer with strong discursive skills in words and logic who is a visual artist — drawing, painting, sculpture, photography — right-handed and with strong physical preference for my left stances in martial arts. I and the few others like me would be curious about what science say on this myth.

  17. Harry Warrick

    I wonder about cross hemispheric individuals. I was tested in my youth and advised that indeed I had cross hemispheric or cross dominance symptoms. At the same time I was tested and found to have an IQ of 144. Not amazing as an IQ compared to many, but it did allow me to adapt and learn in new ways during my lifetime, at least to date.
    I understand your thoughts on the research results. Certainly other research points to the fact that after brain trauma one can start to use other areas of the brain to take over functions for damaged areas.
    The research you mention with the mathematician verses the artist brain scans were likely not conducted while the part was actively performing their said specialized skill (especially on the corpses). If so, then we would see certain areas of the brain that showed higher levels of activity that others. Also that the activity would be in many people in different areas since the neural pathways would have been built in their brain based on all environmental factors, age at the time of learning, and brain trauma earlier or later.
    Also if you want your IQ to drop 50 points or more go to YouTube and you will find a renewed debate on Flat Earth. I went down that rabbit whole for 20 minutes today just out of interest in the failure of our educational system.

    • Victor

      One of my co-workers believes in Flat Earth —in the 21st century. It boggles my mind.
      He conscribes other ‘conspiracy theories’ as well, but believing in an idea in spite of overwhelming proof to the contrary takes the notion to whole further level of ignorance.

    • Charles Fuchs

      The failure of our educational system is very apparent on the roadways as you drive anywhere. People have become more and more stupid! Brain fog is everywhere. They think paying attention costs money!!

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