Can the acquired skill of writing with both hands make your mind sharper and faster? Can schoolchildren’s training on using the non-dominant hand improve exams? Such statements have been expressed for over a hundred years.

Right-handedness or left-handedness - one of the deepest puzzles of neurology. We still know very little about what it means for the brain to be left-handed or right-handed, or what effect ambidexterity will have on the brain.
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By four years we have developed a preference in using one hand instead of the other, which remains with us until the end of life. Most of us prefer the right hand, and most of the rest - the left. But a tiny part, less than one percent, live in ambidexstra. This property is innate and partly controlled by genetics. It is also observed in other animals, including primates. But the reason for the prevalence of right-handedness is still not clear.

Two hands, two brains?

We know that the choice of the hand is related to the asymmetry in the brain: the left hemisphere controls the right side of the body, and vice versa. Most of it contains speech centers, and therefore it is often claimed that it prevails over the right.

Historically, left-handed people were stigmatized, punished and forced to relearn, but at the end of the 19th century a movement appeared that advertised the benefits of ambidexterity. In 1903, John Jackson, a senior teacher of the grammar school in Belfast, founded the Ambidextral Culture Society. Jackson and his followers believed that the hemispheres of the brain differ and work independently, and that the prevalence of right handedness wastes half the educational potential.

Jackson wrote that with ambidexterium workouts, "each hand will be independent of the other in the production of any work ... if necessary, one hand will be able to write a letter and the other will play the piano without losing concentration or ability." And the universal application of ambidexpression, as a result, should have led to a brave new world of two-handed citizens with doubled brain activity.

And although Jackson's statements were based on scientific observations, they were rejected as a result. Nevertheless, such ideas still exist, and some believe that learning to use a non-dominant hand can have a beneficial effect on brain activity. People who make such statements usually refer to neuroplasticity , that is, the ability of the brain to change its structure and functioning in response to the experience.

False statements

Take, for example, Whole Brain Power Consulting - “a revolutionary brain training program” by Michael Lavery, who has declared himself “a pioneer in the field of applied neurology and brain work”. Through a set of “simple ambidexterity, writing and memory workouts,” he promises “to spur your mental outlines, your memory, overcome stress, sharpen your mind, raise your spirits, improve sleep, etc. etc.". And all this for only $ 67 (4400 r).

At various sites, you can find statements that training the use of a non-dominant hand can develop your creative abilities. In his blog Good Financial Cents, certified financial designer Jeff Rose claims that using the “opposite” hand to perform daily tasks like brushing your teeth “will strengthen nerve connections in the brain and grow new ones.” And also "will help your brain cells grow."

Rose talks about the fact that "the non-dominant hand is connected with the non-dominant hemisphere of the brain, because we exercise less frequently ... Therefore, when you use the non-dominant hand, both hemispheres are activated, which can lead to a change in thinking and an increase in creative potential."

And although the structure and functioning of the brain, of course, can greatly change under the influence of new impressions and training, and your brain does continue to grow new cells throughout life, the question of how ambidexterity affects brain function is still poorly understood. There is no scientific evidence that training a non-dominant hand can lead to such positive effects.

And although Rose correctly writes that the non-dominant hand is connected to the non-dominant hemisphere of the brain, his suggestion that this hemisphere does not train so often is wrong, since all behavioral scenarios, even those that activate brain regions that exist only in one of the hemispheres, activate both hemisphere.

Risks and benefits

Some neurologists believe that training ambidexterity can cause harm, based on some studies, according to which congenital ambidexterity correlates with the worst results in scientific disciplines and mental health. These studies show that ambidextras are worse than left-handers and right-handers, they cope with different tasks, especially arithmetic, memory problems and logical exercises, and that ambidexters have language problems and attention deficit disorder. Ambidexterity is also associated with an accelerated decrease in brain volume during aging.

“The two hemispheres of the brain are not interchangeable,” says cognitiveist Michael Corballis of the University of Auckland, who conducted several studies on ambidexters and their academic success. “This asymmetry may have arisen as a result of evolution so that the two parts of the brain can develop specialization. If you try to cancel or change this effective setting, you can come to psychological problems. ”

However, these are only assumptions, and there is no evidence that ambidexteria training leads to problems. On the one hand, science believes that inborn ambidexterity can have some drawbacks, not only in the work of the cognitive apparatus, but also in mental health. On the other hand, it is not at all clear whether ambidexterity training will lead to the same consequences for the brain as congenital ambidexteria leads to.

Therefore, the question of how the training of the nondominant hand can affect the brain does not have a simple answer.