Making Sense of Left-Handedness: An Interview With Howard Kushner, PhD

December 5, 2017

The practice of forcing left-handers to use their right hand is a long as human history and found in most societies. In fact, the words “left” and “left-handed” are synonyms for “defective” or “sinister” in almost all the world’s languages. More in this interview.


Howard I. Kushner, PhD is the Nat C. Robertson Distinguished Professor of Science & Society Emeritus at Emory University in Atlanta, Georgia and the John R. Adams Professor of History Emeritus at San Diego State University. A historian of medicine and the neurosciences, he has authored a number of books, including A Cursing Brain? The Histories of Tourette Syndrome (Harvard University Press, 1999) and American Suicide: A Psychocultural Exploration (Rutgers University Press, 1991). He has also been involved in a collaborative study of Kawasaki Disease at The University of California, San Diego, supported by a series of grants, including the National Institutes of Health, the National Library of Medicine, and the Kawasaki Disease Foundation. His most recent book is On the Other Hand: Left Hand, Right Brain, Mental Disorder, and History, published in August by Johns Hopkins University Press. He took some time to answer a few questions about his newest work.

Greg Eghigian, PhD (GE): How did you become interested in the subject of left-handedness?

Howard I. Kushner, PhD (HIK): My interest in left-handedness came from a combination of personal experience overlaid with clinical observations. It began with my own and my mother’s left-handedness. The lack of left-handed desks in my grammar school no doubt contributed to my inability to master the cursive writing skills, but otherwise my left-handedness presented no drawbacks. I was an acceptable first-baseman and a useful Little League switch-hitter. In contrast my mother, a natural left-hander, had been forced to write and sew with her right hand, a practice enforced by educators in the Philadelphia public schools in the 1930s. Like other left-handers who were forced to switch, mother had a number of reading difficulties that she masked but could not overcome.

The second impetus for this study was based on my observations of pediatric patients at a movement disorders clinic at Brown University’s Memorial Hospital of Rhode Island in 1994 and 1995, where it appeared that the patients with Tourette syndrome and attention deficit disorder appeared to be left-handed in a greater proportion than the 10% of the population predicted. Using the standard handedness inventory, we uncovered an excess of left-handers among our patients. However, the findings were statistically inconclusive due to our small sample size and lack of controls. I had planned to undertake a full-blown research project on handedness and pediatric movement disorders. The project was sidetracked, however, by my work on the etiology of Kawasaki Disease, a sometimes-fatal pediatric vasculitis.

In the fall of 2000, I moved to Emory University, where I worked on addictions and self-medication by people with chronic diseases, especially those with pediatric movement disorders. Again, because a disproportionate number of this population appeared to be left-handed, I was propelled to consider the role of handedness in learning disorders.  More than a decade and a half after my experiences at Brown, I resolved to stay focused on the mysteries of left-handedness. The result is my new book On the Other Hand: Left Hand, Right Brain, Mental Disorder and History.

GE: You say toward the end of the book that “The history of left-handedness parallels that of other disabilities.” How so, and should we consider being left-handed a form of disability?

HIK: I examine left-handedness in the context of disability studies that has contested the classifications and meanings of disability, forcing researchers to reexamine their assumptions and attitudes about disability while challenging public policies aimed at them. The “profane” left hand has historically been opposed to the “normal,” often sacred, right hand. This antagonism was informed by both transcendent and culturally specific beliefs. As I argue the damage produced by discrimination against left-handers was greater than the supposed pathology resulting from left-handedness. By the early 20th century the stigmatizing practices toward left-handers was replaced by scientific, social, and educational theories that (re)authorized the view that left-handedness was a disability as it authorized forcing left-handers to become right-handed. Moreover, the assumption of so many researchers that left-handedness is connected to learning disabilities has contributed to the persistent belief that left-handers are abnormal.

GE:One of the confusions surrounding estimates of the prevalence of left-handedness, you note, involves how it is defined. In what ways have societies and groups differed in how they identify someone as left-handed?

HIK: The reported prevalence of left-handedness is strongly influenced by how handedness is defined. In China, the prevalence of handedness was obtained by measuring the handed activities that were most essential to the Chinese when they were being measured. In earlier epochs, what mattered most was what hand one used for eating. By the late twentieth century, writing and drawing had become the test for handedness. Because natural left-handers were routinely made to write and draw with their right hands, little attention was paid to these people’s continued reliance on their left hand for other tasks. This is true in other societies. Maria De Agostini and colleagues1 asked their Côte d’Ivoire and Sudan subjects to identify pressures to change their writing, eating, or other handed activities. The team reported that in both societies the greatest pressures aimed to change left-handed eaters.

The instruments and methods used to assess handedness pose a major problem for determining the prevalence of left-handedness. New Zealand psychologist Michael Corballis2writes that there is “little agreement as to precisely how handedness should be defined or measured” even though “nearly all people readily identify themselves as being either right-handed or left-handed.” Although it is difficult to pin down exact percentages, the reported rate of left-handers tracks with the prevalence of discrimination against left-handers in any society: the lower the reported prevalence of left-handers in a society, the greater the stigma and discrimination toward left-handers.

GE:You discuss the practice of “retraining,” forcing left-handed individuals to become right-handed. When and where in history has this approach been adopted, and what kind of consequences did it have for those who were “retrained?”

HIK: The words “left” and “left-handed are synonyms for “defective” or “sinister” in almost all the world’s languages. Eating and writing with the left hand was, and often remains, a profane practice; the sacred, in contrast, is restricted to the right hand. In the 20th century, these beliefs were reinforced by medical theories. The practice of forcing left-handers to use their right hand is a long as human history and found in most societies.

The methods employed to achieve right-handedness were often tortuous and humiliating, including corporal punishment and immobilizing a child’s left hand. By the mid-20th century, the majority of Western educators and physicians endorsed the view that left-handers often exhibited mental and cognitive disabilities. To combat these dangers, they endorsed “retraining” left-handers to be right-handers. The chief psychiatrist of the New York City Board of Education warned that, unless retrained, left-handed children risked severe and life-long cognitive deficits.3

As the testimonies of the retrained reveal, translating theory into practice often exposed children to a greater danger than that allegedly posed by left-handedness. Recalling his experiences in a mid-1920s elementary school, one British left-hander reported that he was forced to sit on his left hand and write with his right hand. When that failed, his teachers tied his hand behind his back. Another pupil related that whenever he used his left hand his teacher poked a cane in his ribs. Retraining was not limited to the powerless. The Duke of York, future King George VI (1895-1952), had been forced to write with his right hand, which probably contributed to his stuttering. The methods used to transform Duke into a right-hander were similar to those reported by other British elementary students.

Retraining was common in the West until the late 20th century. Many French schoolteachers continued to force left-handers to write with their right hands well into the 1970s. “When I was in school,” wrote 64-year-old Gisèle, “the nuns were teachers and they forbade me to write with my left hand because they said that the LEFT-HANDED were possessed of the devil.” She was regularly hit with a ruler, and her hands were tied behind her to restrain use of her left hand. A 61-year-old German engineer from Wiesbaden recently reported his retraining led to “psychological and health problems” later in life. Along with other retrained German left-handers, he set up an online forum where others who post their own experiences of having been retrained. The adverse consequences of reported reveal how these humiliations reflected wider beliefs that difference is synonymous with abnormality.

GE:I get the sense that genetic and evolutionary arguments about the etiology of left- and right-handedness have grown in prominence since, say, 1970. To what extent is that a fair assessment of more recent research developments?

HIK: This is especially the case since the mid-1980s. Today, when the cause of behaviors and traits increasingly are assumed to be genetic, investigations into left-handedness have focused on searching for the putative gene or genes that determine handedness. Although genetic hypotheses have been proposed since the early 20th century, today’s genomics relies on sophisticated statistical and imaging tools that take advantage of the recent elaboration of the human genome.

These studies often gain wide, if fleeting, media coverage. For instance, a widely publicized 2007 BBC report claimed a British team had identified “the gene for left-handedness,” which also increased the risk for mental illnesses, including schizophrenia.4 As is often true when the media translate scientific hypotheses, the complexities and caveats of researchers are frequently sacrificed to the demands of provocative headlines and accessible summaries. The studies themselves are not bad science. Indeed, like the studies I discuss in my book, they are methodologically sophisticated and intriguing. But identifying the etiology of handedness always turns out to be much more complex than it appears, not least of all because there is no agreement about how to define left-handedness.


1. De Agostini M, Khamis AH, Ahui AM, Dellatolas G. Environmental influences in hand preference: an African point of view. Brain Cogn. 1997;35:151-167.

2. Corballis MC. The genetics and evolution of handedness. Psychol Rev. 1997;104:714-727.

3. Blau A, Lowrey LG (Ed). The Master Hand: A Study of the Origin and Meaning of Right and Left Sidedness and Its Relation to Personality and Language. American Orthopsychiatric Association, Inc.; 1946.

4. Gene for left-handedness is found. BBC News. July 31, 2007. Accessed December 5, 2017.