In a world made for right-handers, a left-handed student finds it difficult to take notes inside the room, where the seats have a folding table, since it is on the right side of the seat. A left-handed teenager learning to play the guitar is forced to turn to a specialty store that has guitars with the strings in the opposite order to those made for right-handed players. A doctor practicing surgery requests the modification of his tools or the ordering of special tools so that he can perform with the required precision the movements he needs to make. A mistake, after all, could be fatal. At the same time, even a handshake looks awkward between a right-hander and a left-hander, who find it difficult to sit side by side at the same table as one’s elbow blocks the other’s elbow…

Difficulties of this kind continue in every other aspect of everyday life in which hand movements are involved, such as handling tools that involve risks of injury, but also in cases where the perceptual differences between people with different preferences for the upper limbs are also evident. . Typically, one item that runs out of stock quickly in left-handed stores is the wall clock. In this the movement of the hands is counterclockwise rather than clockwise and the numbers move from right to left of the clock and vice versa.

“Until the recent past, the environment for left-handed people was not so friendly and human achievements, for reasons of economy, were all designed for right-handed people, with the result that left-handed people are simply forced to adapt”, Georgios Grouios points out to APE-MPE. professor of the Department of Science of Physical Education and Sports of the Aristotle University of Thessaloniki (AUTH).

He explains that this fact makes left-handed people more vulnerable to injury and states: “in an electric saw, for example, that cuts wood, the buttons for its operation are on the right side of the device as right-handed people open and close the saw with the thumb. A left-handed person to use the same machine will have to put his hand over it, and if he uses the saw for many hours, he is more at risk of an accident.” By the same logic, he says, the pot used by a right-handed person pours the coffee from the spout into the cup from the inside of the hand, while a left-handed person with the same pot should pour the coffee by tilting it towards the outside of the hand . “This movement is not ergonomic, it is not anatomical, and these people can easily injure themselves,” he adds.

Left-handed products that sell out the fastest

In recent years, however, special stores have been created that sell the same items, adapted to meet the needs of left-handed people. In them, those interested can find keyboards, mice, rulers, erasers, pencils, notebooks, crayons, coffee mugs, writing handles, eating knives, etc.

The items that disappear from the shelves at the fastest rate are wall clocks, scissors, buckets, mugs, vegetable peelers, pens, can openers, scrapers, and pruning shears.

Lateralization: The motor cortex of one hemisphere prevails over the other

Mr. Grouios, who has been dealing for the last twenty years with hand preference as one of the lateralization indicators of the human body, notes that this specific behavior is part of the kinetic asymmetry and in addition to the preference for the upper limbs there is also a preference for the lower limbs, eye preference as also a preference for movements such as crossing the arms and legs and intertwining the fingers.

“In general, lateralization reflects the predominance of the motor cortex of one hemisphere over the other in the human species. It is a behavior, which is interpreted with more than one theory, without it being clear how it arises,” he adds. Answers to this question have been given by genetic, environmental, developmental, evolutionary and pathological theories, while it is considered that the causes of this behavior are more than one.

In terms of percentages, 90% of the population is concentrated in the category of absolute right-handedness, while a percentage of 3 to 4% is at the other extreme, that of absolute left-handedness. The remaining percentage, a 6 to 7%, is distributed between these extremities, in the middle of the distribution, where upper extremity ambidexterity exists. This means that a person performs complex dexterous movements equally well with both hands, or performs some movements very well with one hand and others with the other. However, ambidextrous people cannot be as well specialized in their movements as completely right-handed and completely left-handed.

Increased rates of left-handedness in clinical populations

At the same time, it has been established that the percentages of left-handed people are increased in clinical populations, people with neurodevelopmental disorders, schizophrenia, depression or manic-depression, which according to the professor of the Department of Physical Education and Sports Science of AUTH, “reflects a different way of organizing the cortex of the cerebral hemispheres in these individuals”.

Best Left-Handed Performances – Famous Left-Handers

On the other hand, many famous people from the fields of science, politics, art and sports are left-handed. They include Leonardo Da Vinci, Albert Einstein, Bill Gates, Jimi Hendrix, Celine Dion, Lady Gaga, Angelina Jolie, five presidents of the United States of America: Barack Obama, George Washington, Gerald Ford, Richard Nixon and Grover Cleveland, the Rafa tennis players Nadal, Jimmy Connors and Martina Navratilova, but also racing drivers Ayrton Senna and Valentino Rossi.

As an explanation, Mr. Grouios states: “left-handed people as a population exhibit certain characteristics, which in certain areas, make them more effective. For example, in some confrontational sports such as wrestling, boxing, tennis and fencing, the techniques adopted by the athletes allow them to be more effective. Also, left-handed people perform very well in subjects that require organization of space and time and thus become very good painters, musicians, architects, librarians, physicists, mathematicians, astrophysicists. Conversely, they may have poorer handwriting or lower performance in language-related subjects.’

When partisanship is transferred to society, religion, politics

The differences, however, between right-handers and left-handers are not only limited to people’s daily lives and professional careers, but are also interwoven with spaces such as those of society, religion and politics. “The left in society, religion and politics is intertwined with evil, while the right with good. We often say: ‘let the new year come in with the right hand’, ‘foot with the right hand’, ‘from the right hand of the father’, ‘may everything go to your right’, ‘we make our cross with the right hand’. This is because the left was socially obliterated and anything left-leaning was out of line. In the past, all these societies eliminated them and this was the reason why many parents and teachers pressured left-handed children to write with their right, so that this movement would not indicate their difference compared to the average behavior of the population”, notes the characteristic Mr. Gruios.

Against this kind of behavior and practices, the professor recommends encouraging left-handers to develop their superiority in various fields, avoiding stressful situations since, as he says, the functioning of the brain does not change with pressure, but also the increasing empathy so that difficulties arising for left-handed people are perceived and facilitated more.

“It is true that in recent years there has been greater sensitivity to specifics and personal data. In this context, left-handedness becomes of particular interest and the changes that this can cause in various fields such as education and society, can make the lives of left-handed people better”, concludes, speaking to APE-MPE, the professor of the Department of Science of Physical Education and Sports of the Aristotle University of Thessaloniki.