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 lifeworkserie.org).  My talk was organized around questions about left-handedness I have been asked repeatedly.

Left-handers like to post lists on Facebook…10 Things Left-handers Should Fear…7 Things Left-handers Should Know…5 Good Reasons to be Left-handed…and so forth.

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 week.

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?

Take Our Left-Handed Questionnaire Here

Response to Question Number 1:

When people are asked about their handedness, most call themselves left- or right-handed based on their writing hand.  Writing is a highly lateralized or sided behavior.  This means that a person consistently uses the same hand to perform the activity.  Although Leonardo Da Vinci was reputedly able to write proficiently with both the right and the left hand, it is a rare person who can do this. However, there are other one-handed behaviors such as waving good-bye or using a push button phone that are not firmly lateralized…a person might use either the right or left hand depending on the circumstances.  It is also common to find people who switch their handedness from one side to the other depending on the activity.  For example, many left-handed writers throw a ball with the right hand.  As one can see, there are many hand use possibilities.  A person can switch handedness side both within an activity…waving good-bye with either the right or left hand…or across activities…writing with the left hand and throwing a ball with the right hand.

Below you will find a questionnaire that I use in my research to measure handedness.   Answer each question as indicated, and if an activity is difficult to rate, act out the behavior or leave a blank for that question.

Download (PDF, Unknown)

Rating handedness for these 20 behaviors in the questionnaire shows that handedness is a sidedness continuum ranging from strongly left-handed for most activities to strongly right-handed.  Based on previous questionnaire results, approximately 56% of respondents rate all 20 items as right-handed while 9% rate all items as left-handed.  The remaining 35% of respondents have mixed-handed scores where the right hand is used for some behaviors and the left hand for others or either the right or left hand can be used to perform a single behavior.

Three facts emerge from this exercise in handedness measurement.

1. One is 6 times more likely to find a strongly right-handed person than a strongly left-handed one.
2. About one-third of people are mixed-handed and can use either the right or the left hand to complete an action depending on the activity and the circumstances.
3. It is normal to be able to use the non-writing hand for other one-handed activities.

In summary, it is normal to write with the left hand but do other things with the right hand.

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

ABOUT THE AUTHOR:

Clare 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-Handedness, is 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.