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Top Five Questions Left-Handers Ask, #4: Will Switching Writing Hands Mess Up My Brain

By: , Posted on: November 22, 2016


Recently I gave a talk titled The Mystery of Left-Handedness at Lifeworks an organization in Erie, PA that promotes life-long learning, health and wellness (see  My talk was organized around questions about left-handedness I have been asked repeatedly.

My five questions below represent issues that arise again and again when I talk to left-handers or when I am interviewed by the media about left-handedness.  I will answer each of these five questions in my five-part blog series of the next several weeks.

  1. I write with my left hand but do other things with my right hand.  Is that normal?
  2. Everyone in my family is right-handed but me.  Why? I thought handedness is genetic.
  3. Are left-handers smarter and more creative than right-handers?
  4. If I try to switch writing from my left to my right hand, will I mess up my brain?
  5. Are left-handers better at sports than right-handers?

Response to Question Number 4:

The practice of forcing left-handers to become right-handers has a long history.  Forced conversion remains an ongoing practice in some parts of the world but I will concentrate on the history of conversion practices in North America and Great Britain. The 19th century Italian physician, Cesare Lombroso, was influential in connecting left-handedness to insanity and criminality.  His writings lent scientific credibility to the idea that left-handedness is an undesirable trait. Left-handers should be converted to right-handers to avoid developing the negative traits that lead to socially unacceptable behaviors.  Early 20th century British, Canadian and American educators adopted Lombroso’s ideas and promoted forced rightward conversions in left-handed children.  These conversion attempts were often conducted with punitive fervor.  Restraining the left hand so it could not be used or striking the left hand when the child tried to use it were common conversion techniques.

In the 1920’s a series of publications presented data claiming that 50% of stutters were left-handers who had undergone rightward conversion.  There were further reports that the stuttering of converted left-handers improved when individuals were returned to their natural left-handed behaviors. The speech center in the brain is located in the left hemisphere for most persons.  One researcher, Samuel Orton, argued that switching handedness interfered with the establishment of language functions in one hemisphere and resulted in the development of speech and language disturbances. These findings connected the rightward conversion of left-handedness to a ‘messed up’ brain that caused speech problems. As a consequence there was a relaxation and widespread elimination of the educational practice of forced rightward conversion of left-handedness over the following decades of the 20th century in North America and Great Britain.

Researchers continue to investigate the possibility that handwriting conversion causes changes in the brain. Studies conducted in the 21st century use neural imaging techniques to record brain activity while individuals write. Right and left hand movements are controlled by the movement control centers of the opposite hemisphere. Movement centers in the left hemisphere control right-hand motions while movement centers in the right hemisphere control left-hand motions. Natural right- and left-handers show primarily opposite hemisphere activity when they write.  Converted left-handers, who now write with the right hand, display activity in both hemispheres when writing. A study published in 2010 found that movement control centers in the brains of converted left-handers show structural differences when compared to these centers in the brains of natural right- and left-handers. It seems that brain development in the movement control areas can be affected by an early experience of writing hand conversion.  However, the researchers did not find a relationship between these brain differences and speech, language or other learning difficulties among converted left-handers.

In summary, connections between left-handedness, handwriting conversion, criminality, insanity and disabilities of language or speech find little support in the contemporary research literature.

Stay tuned for the next articles appearing throughout the end of November for answers to the next questions.


Clare_PoracClare Porac received her Bachelor of Arts degree in sociology from Duquesne University and her MA and PhD degrees in psychology from the New School for Social Research, and is presently Professor of Psychology at Penn State Erie. She has authored or coauthored 63 research articles and has presented 66 conference papers on her human laterality research; she has an additional 55 publications and 50 conference papers on other topics. You can read her full biography here.

Professor Porac’s new book, Laterality: Exploring the Enigma of Left-Handednessis a comprehensive overview of scientific research on laterality that not only tells us what is true, but also debunks commonly held misperceptions. Each chapter is based on a question or questions covering diverse topics such as genetic and biological origins of handedness, familial and hormonal influences on handedness, and the effects of a majority right-handed world on the behaviors of left-handers.


If you would like to purchase a copy of Laterality: Exploring the Enigma of Left-Handedness at up to 30% off the list price and free global shipping, visit the Elsevier Store. Apply discount code STC215 at checkout.

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