January 2024
Leonardo Da Vinci’s mid-15th century notebooks include experiments with writing with both hands at the same time in the same direction, writing in mirror writing, upside down, writing with both hands in different directions, and so on, indicating that he was ambidextrous. For years, it was thought he was left-handed but learned to write with his right hand. Recent studies by the Uffizi Gallery in Florence, Italy, indicate that he was equally proficient with both hands and his drawings and writings indicate this. The drawings and writings showed equal pressure in each stroke and produced in the same style, debunking the other theory that some parts of his work were done by an apprentice.
Current studies on hand dominance are producing a lot of new and interesting insights. I’ve written something about this before, but here I want to elaborate upon the psychological implications of the subject.
About 90 percent of people are right handed, while the remaining 10 percent are either left handed or with some degree of ambidextrousness, though only about 1 percent are truly ambidextrous.
What is happening in the brain? The examination of those who have had surgery to fix their epilepsy that involved having their brains surgically split, has shown that the two halves of the brain are responsible for different tasks. The left side controls language and the right emotional and nonverbal functions. When a person has a right-hand preference, the brain’s left hemisphere is dominant. Left-brain dominant people tend to be better at analytical thinking, while right-brain dominant are more ‘big picture’ thinkers. In mixed-handedness, one side of the brain has no clear dominance over the other. Ambidextrous people are using both sides of their brains about equally. Herein lies some difficulties that may arise for the ambidextrous. These issues that can be corrected with training.
An article published in a neuroscience journal in 2023, identified an association between dyslexia and ‘mixed-handedness.’ In the study context, ‘mixed handedness’ referred to both ambidexterity (no hand preference for a task) and inconsistent hand use (using different hands across different activities.) A strong link was found between dyslexia and mixed-handedness, and also, interestingly enough, ADHD (attention-deficit/hyperactivity disorder). Which hand to use, and how? What to do next? A symmetrical brain thinks differently. In typical brains, language is rooted in the left hemisphere and neural networks that control attention are anchored in the right hemisphere, but brains without a dominant hemisphere operate in other ways. Maybe our education system just isn’t geared to these differences.
Hand dominance is inherited, though the old practice of making left handed children write with their right hand often leads to ambidextrousness, or left-right confusion. La sinestra, from which comes our English word “sinister”, literally means “left” and being left handed was an indication of being associated with the devil (according to some misguided people).
Being ambidextrous is useful. A friend of mine once worked in casinos and she was able to be much more efficient way than her right or left handed counterparts. I first came to know her when she was a university student of mine. I noticed then that she seemed to have a certain linguistic blindness to particular words. When she became a friend, I continued, and continue, to proofread her creative writing and notice that the problem continues. I only recently discovered that she is ambidextrous.
Now, I am also ambidextrous, but I am not dyslexic. I’ve been mulling about this and conclude that because I was introduced to playing musical instruments at a very young age, I was able to develop my dual-handedness, without too much confusion. I do retain a bit of left-right confusion when opening jars, as do others with ambidextrousness, but the clue to ironing out incipient problems is getting the person to engage the hands in related but different tasks at once. I encourage others to explore this. Maybe taking up an instrument, or experimenting – as Da Vinci did – with writing/drawing with both hands at once could be the clue to strengthening one’s attention and linguistic skills , and thus avoiding psychological issues associated with a symmetrical brain.
