Forced Right-Handedness

“Use your good hand!” my grandmother always said – meaning: use your right hand, not your left! “But I had always done everything with my left hand: writing, painting, shot put,” says Anneliese Meier, who does not want to give her real name for professional reasons. “Then I would get a slap on the fingers,” recalls the 62-year-old. An estimated one in ten people is left-handed; some surveys assume there are even more left-handed people. In the past, these people were retrained, as was Anneliese Meier. When she started school, she had to write with her right hand: left-handed people were considered abnormal, and teachers were vigilant. “My right hand was constantly cramped. That's why I sometimes built a screen for myself. Then the teacher couldn't see that I was writing with my left hand in between.”

If the teacher had looked at the sheet of paper, he might not even have noticed which sentences the student had written with which hand: The handwriting of left-handers who were retrained at an early age usually looks just as uniform and delicate as that of a typical right-hander.

Stefan Klöppel is not surprised by this, at least not anymore. At the University Medical Center Freiburg in 2007, he discovered that left-handed people who have been retrained to use their right hand have also had their brains retrained, at least partially (to study).

Generally speaking, the left hemisphere of the brain is responsible for writing in right-handed people, while the right hemisphere is responsible in left-handed people. The nerve pathways from the motor and sensory centers of the two hemispheres are criss-cross-connected to the two sides of the body. However, it was long unclear how this works in left-handed people who have been retrained to use their right hand.

Stefan Klöppel had 16 ordinary right-handed people, 16 ordinary left-handed people, and 16 retrained left-handed people complete three tests: First, they were asked to pantomime situations such as throwing, brushing their teeth, and playing tennis – this was to test how left-handed they were. Then the test subjects were asked to write small double Ls, i.e., thus two loops, by hand for several seconds, once with their left hand and once with their right hand – this was to test their handwriting. They were also placed in a functional magnetic resonance imaging (fMRI) scanner, where they were shown various symbols and asked to press a button for certain images, for example, a sun with their left index finger and a star with their right index finger. This was to find out whether the brains of retrained left-handers work differently.

The pantomime test revealed that the retrained left-handers in the test group wrote with their right hand, sometimes with both hands – but most of them used their left hand for other activities. This made it easy to identify the retrained left-handers among those who wrote with their right hand. The situation was different in the handwriting sample and symbol test: "The handwriting of the retrained left-handers and the pure right-handers looks very similar. And in the fMRI test, both groups were equally quick and made a similar number of typing errors," says Stefan Klöppel. The fMRI showed that the areas of the brain responsible for movement control were dominant in the left hemisphere of the retrained left-handers – as in normal right-handers and unlike normal left-handers.

The retrained area of the brain is the primary sensorimotor cortex. “This is where movement is controlled. The more successful the retraining was, the more the movement was controlled by the actually non-dominant left hemisphere of the brain,” says Stefan Klöppel.

However, the brain was not completely reorganized. “The planning and control of movements still took place in the right hemisphere,” says Stefan Klöppel. In the fMRI images, two regions lit up more strongly in the right hemisphere than in the left: the dorsal premotor cortex and the supramarginal gyrus. "The dorsal premotor cortex is the classic region for controlling motor function. And although the supramarginal gyrus is responsible for many different things, one of its functions is to serve as an alternative region when the dorsal premotor cortex is already busy," says Stefan Klöppel. And retrained left-handers need a lot of computing power in these areas of the right hemisphere; they don't just have to coordinate their usual left hand, but also their unfamiliar right hand. This was also evident in the fMRI: both brain regions were more active in retrained left-handers than in pure right-handers and pure left-handers.

When retraining to become right-handed, only some of the brain activity is shifted to the left hemisphere, while other activity remains in the right hemisphere. This may be because planning and coordinating a movement is cognitively more demanding than simply executing the movement. It is also conceivable that the planning of a movement can be easily decoupled from the motor execution of the action, and that there is therefore little pressure to transfer these planning regions to the left hemisphere of the brain as well.

The brain regions responsible for planning and coordination are superior to those responsible for immediate control. Retrained left-handers have to cross-route their input from the right to the left hemisphere of the brain, while also overcoming the natural impulse there. This requires more work from the brain. Perhaps this even explains why Anneliese Meier was so unsuccessful in her attempts to learn instruments. “My older sister is right-handed and had a guitar and an accordion. I wanted so much to play them, but I just couldn't,” says the retrained left-hander. Stroking strings and pressing keys was something her right hand could do poorly at best – the coordination was too difficult.

In a follow-up study, Stefan Klöppel found another difference between the brains of retrained left-handers and pure left- or right-handers: “The retrained left-handers had less gray matter in the middle part of the left putamen,” says Stefan Klöppel. The putamen is part of the basal ganglia. The front part near the forehead is responsible for cognitive tasks, while the rear part controls movement – the tasks overlap in the middle. “It is completely normal for the volume of the basal ganglia to decrease in the first years of life, as this is probably due to the breakdown of unnecessary nerve connections,” says Stefan Klöppel. However, this effect was particularly strong in retrained left-handers in the transition area between the cognitive putamen region and the movement-controlling putamen region. “That really surprised us,” recalls Stefan Klöppel. “We had actually expected the gray matter to increase in this area, just like muscles do during exercise. After all, it's a kind of training when left-handers constantly use their unaccustomed right hand.” The neurologist does not know the reason for this strange research result.

However, he has gained an important insight: “In retrained left-handers, even simple movements place greater demands on the brain. However, there is no question of excessive strain, nor of underuse in the now less active regions of the brain.” Stefan Klöppel thus contradicts those who claim that in retrained left-handers, the brain is sometimes overstrained and sometimes underused, and that this is what makes people ill.

There are retrained left-handers who attribute their psychological problems to retraining. Bedwetting, poor concentration, memory problems, and fear of failure are most commonly cited.

However, there is no scientific evidence for this, says psychologist Alan Searleman from St. Lawrence University in the US. He has conducted extensive research on left-handed people. "A few years ago, we became aware that Johanna Barbara Sattler in Germany was complaining that there were very negative consequences for left-handed people who had to write with their right hand. Her claims surprised us, and we have no data to support them." So far, the question of how retraining from the left to the right hand affects the psyche has apparently not been empirically investigated. There is also no study on this topic in the PubMed database for medical publications.

Stefan Klöppel does not believe that retraining itself is responsible for psychological distress: “It is more likely the psychological stress that one is exposed to when forced to use the right hand, even though it feels wrong.”

Anneliese Meier no longer holds a grudge against her grandmother. “It was just a different time.” Today, left-handed children in Germany are hardly ever retrained. On the contrary, parents and teachers are encouraged to place spoons, pens, and other utensils in front of the child so that they can decide for themselves which hand to use. Left-handedness is no longer a stigma but is now considered a sign of particularly clever minds (see info box on myths about left-handed people). How the brains of retrained left-handed people work is therefore no longer something that can be studied in this country.

Further reading

• Klöppel, S. et al.: Can Left-Handedness be Switched? Insights from an Early Switch of Handwriting. In: Journal of Neuroscience, 2007; 27 (29), pp. 7847–7853 (to the text).
• Klöppel, S. et al.: Nurture versus Nature: Long-Term Impact of Forced Right-Handedness on Structure of Pericentral Cortex and Basal Ganglia. In: Journal of Neuroscience, 2007; 30 (9), pp. 3271–3275 (to the text).
• Ocklenburg, S. and Güntürkün, O., The Lateralized Brain: The Neuroscience and Evolution of Hemispheric Asymmetries, London: Academic Press, second print, 2024.

First published on February 22, 2013
Last updated on October 25, 2025