Being left, a very normal 'peculiarity'

2005/01/01 Agirre, Jabier - Medikua eta OEEko kidea Iturria: Elhuyar aldizkaria

• Osasuna

In the 1970s, scientists considered the left as a characteristic of the person, rather than a mistake to correct. But since then, teachers and parents have wanted to teach many children to use the right instead of the natural hand. And still today that vast minority has to live in a world designed for the right, where most kitchen utensils are designed for the right, and musical instruments, such as guitar and hand sound, are played with the right hand.

Why is it left?

Researchers do not agree on why a person is right or left. It seems that if the father of a child is left, the possibility of being left is 10%, 20% if it is mother, and if the two parents are left, the probability of the child also being left rises to 85%. However, half of the children who have both parents on the left are on the right. Why? Will education influence?

Another drawback for researchers who prioritize genetic inheritance is that of Bikiena, as one of the twins may be the same proportion as the left (25%).

Regardless of the genetic weight, neurological reasons are accepted by all researchers. Being left or right is limited by the brain.

However, until the child is between 5 and 7 years old this point is not fully consolidated and until then it is necessary to be patient if the child tends to do all things with the left hand. We will have to teach you how to do it well, just as it is taught to the right, but respecting its natural tendency, helping you to get enough skill so that you do not have delay in learning, but in no case forcing you to use the other hand.

That's the worst thing to do, forcing the child to be right. Today, it is clear that the use of the left side does not imply a delay in development in any area, but that the use of the right can have negative consequences for the child in his psychomotor development.

According to researchers, most people at birth are left to right, that is, theoretically they have the same ability or ability to use both hands. However, the laterality of the child is noticeable when it is about two months old, seeing if, for example, it takes the toys to the right or left. But, as already mentioned, these data are not definitive, since it takes a few years to fully consolidate.

Today, therefore, there is, at least in theory, no problem to be left. On the other hand, throughout history there have been illustrious left: Aristotle, Nietszche, Leonardo da Vinci, Picasso, Napoleon, Marilyn Monroe or Bill Gates, among many others. In 1975 he was appointed on 13 August for the first time the International Day of the Left. A curiosity is that in the USA there is a small town in which all the inhabitants are left, called Left Hand.

Key questions

• Why was it wrong to be left? In the Gospel of Matthew it is said that on the day of the Last Judgment Jesus will say to those sitting on his left: “Turn away from me, cursed!”
• Is there animal on the left? Yes, depending on the possibilities are 50%. And among polar bears, for example, there is no right.
• And do they have more diseases? According to statistics, we live less years. But this is because there are more left-wing men than left-wing women and their mortality rate is higher.

Contribution of neurology

The left have always been considered abnormal or worse (in almost all languages the word left has been synonymous with clumsy, wrong or malignant), and for centuries they have been directed to correct their ‘mania’.

Modern neurology clarified many things in the 19th century. In the middle of the 20th century. Experts of the time, led by the French surgeon and anthropologist Paul Broca, showed the functioning of the brain. They showed that our brain is divided into two hemispheres and that each has its specific functions. The left hemisphere governs oral expression, mathematical calculations and the movement of the right body, while the right is the perception and vision of space, music and movements of the left part of the body.

The brain controls the body crosswise and, as usually the left part of the brain predominates, most orders are directed to the right of the body. In left-wing people, however, the right hemisphere predominates, directing the orders to the left of the body.

The dominance of either hemisphere is known as laterality. Laterality is total when a hemisphere directs and governs the same face in the hand, foot, and eye. But when the left predominates in the hand and the right eye (or even vice versa) there is talk of cross-lateralization.

That said, it seems that the left should have a greater ease for the perception of space and a greater artistic sensitivity, but at the same time more clumsy for verbal expressions and numerical calculations. However, it is not possible to demonstrate this type of difference, since the right hemisphere often takes care of the functions of the left hemisphere, to the detriment of its own. There are even clumsy leftists than the right in terms of skills related to the perception of space.