Left versus right

2002/02/25 Kortabarria Olabarria, Beñardo - Elhuyar Zientzia

• Anatomia/Fisiologia

The great British scientist Isaac Newton was also left-wing.

The human being from birth has the brain structured in a certain way. Although the brain is the only organ, it is double; it is formed by two hemispheres that work together and have a constant communication. Communication between the hemispheres occurs mainly through the corpus callosum. The corpus callosum is a set of fibers found between the two cerebral hemispheres. According to experts, this batch is made up of approximately 200 million fibers.

The two cerebral hemispheres seem very similar, they seem the same but they are not. In most cases, one in two hemispheres prevails over the other. On the right hand side the left hemisphere controls the right side of the body, while on the left the right hemisphere predominates.

Each hemisphere has control over some functions, as certain neural systems of the brain are found primarily in one of the hemispheres.

Thus, the left hemisphere regulates logic and mathematics, the ability to speak, to write… and the right controls the emotions and functions related to creativity. This specialization of the hemispheres suggests that the left are more sensitive and imaginative, but at the same time more clumsy and slow to speak.

Right with force

The brain is a single organ, but it is divided into two hemispheres.

What if your child is left-handed? Do you have to try to fix it? From generation to generation, society has worked to turn the left into right, until they become considered sick. Today being left does not assimilate to illness, but there are still those who think that being left-handed is something to be solved. About 10% of all people are left-handed and are not inferior to the right neither in intellectual nor physical capacity.

The fact that most children are skilled does not mean that the left are suffering abnormality. However, it is clear that in today's society the left will have more problems than the rest, as the world is designed for the right. Perhaps that is why many parents try to transform the left into the right, without realizing that they are making a mistake.

Wild apes tend to use both hands.

Forcing a left-wing child to use the right can be a way of frustration, as doing things with his weak side can feel misunderstood, act without security, and become introverted. The child may think that being left-handed is also a disease and therefore may lose confidence.

But things are not always what they seem. In the case of children, being left or right is not something that can be seen suddenly. When they are young, children are able to use both hands, they still have no choice to use one hand or another, sometimes they use one hand, the next hand and often both at once. When it reaches 4 years begins to decide the dominance of one of the hands. If not, the child may have a motor problem. By age 7-8, it is already known for sure whether the child is left or right. To know this it is enough to look at everyday tasks: what hand you use to write, with what paw you hit the ball, how you remove the paper to the candies…

Left-handed beles, right whales…

Most animals use more than one part of the body than the other. However, they are usually individual decisions, not trends of the whole species. New Caledonia candles, like humans, tend to use the right side. Therefore, research on this type of sail is gaining importance. In fact, experts believe that data on some of the brain's functions can be extracted from these research.

There are many left parrots.

The veil of New Caledonia is known to be fast. In studies carried out on this bird until 2 years ago, it was stated that this veil is capable of using twigs and tubules to extract insects from the cracks of the trunks. Without agreeing with these results, three New Zealand researchers have been investigating the crow for the past two years. They have concluded that the utensils used to obtain food are manufactured by the raven itself.

The issue is serious. And it is that the use of tools that have been found somewhere to do something – many animals do – is one thing, but the fact of making specific tools for this task means something more, that this animal has some intelligence. The conclusions of the research are not limited to that, as researchers have seen that the veil of New Caledonia to elaborate its work tools is mainly used on one side of the body.

To realize this, researchers have spent hours observing the work of candles. For the manufacture of tools, the New Caledonia grass uses the leaves of the Pandanus utilis tree as raw material. These leaves are usually long and narrow, of a certain consistency, with thorns on the edges. The veil, with the beak, cuts a sheet of about 18 centimeters in length and a centimeter in width.

To do this work you always start working on the sharpest side of the blade. Usually choose the left edge of the leaf to work and with the help of the short right eye with the right part of the beak. Experts are unaware of the reasons why the veil of New Caledonia works this way, since from the other side it would be cut exactly the same. The study analyzed the work of 3,700 sailboats.

More left/right

There are also countries that believe that birds flying to the left bring bad luck.

Besides the veil of New Caledonia, there are few animals that use much more one side of the body than the other. In birds, for example, many parrots and cocoa use the left leg to hold food or bring food to the beak. On the contrary, wavy whales have a higher propensity to use the right margin, which is evident when they catch food or hit the water with the tail. Dogs, cats and horses also like to use one side than the other.

What happens to chimpanzees is more curious. Among wild chimpanzees there is no clearer tendency to use one or the other difference, half and half occur, while in chimpanzees living outside their natural environment the trend is evident towards a greater use of the right hand. According to anthropologists, the exit of animals from their natural environment facilitates changes in attitudes and habits. In these cases neither are observed species behaviors.

In order to have more data on the superiority of either side, researchers from the Atlantic University Hopkins and Dahl have conducted research on monkeys. 134 couples of chimpanzees (mother and puppy) were investigated. Researchers conclude that genes and birth order have a great influence on having chimpanzees on the left or right. The first chimpanzee babies are more likely to be left-handed than the descendants.

Do these investigations serve human beings? One knows, but, as is evident, in human beings the newborn has many possibilities of being left if his parents are left… Therefore, there too much influence genetics. However, experts consider that there are more factors: the age of the mother, the incidents that have taken place during pregnancy, the neonatal environment, the influence of ultrasound… the usual debate: are we born or made?

Many difficulties for the left

Like many other scholars, Mari Curie, left-wing mathematics and physics, received the Nobel Prize in Physics in 1903.

It has also been said elsewhere in these pages: this world is not designed for the left. The question is limited to having problems with the tools used today, but throughout history the left have seen red.

• The use of language can be representative to publicize beliefs about the left. For example, from Russian to the left is said na levo, that is, unreliable. The left, in English lyft (weak), in Latin sinister (wretched), in French (wrong), in Italian mancino (false), in Polish lewo (illegal), in German linkisch (shameful), in Portuguese canhoto (bad), in Finvasenkatine (something to be repaired), in Danish inappropriate (in desejt).
• Pythagoreans recommended always entering the sacred places on the right, from the divine, and leaving on the left, from the void.
• "Good is to the right and bad to the left" Aristotle.
• Meeting a left any day of the week is unlucky except on Tuesdays. There are also countries that believe that birds flying to the left bring bad luck.
• According to Christianity, blessings can only be done with the right, the devil is the left… Everything that comes from Islam on the left is dirty.
• According to a book of psychiatry of 1921, being left-handed can be assimilated to madness.
• The majority cannot touch marriage clothes with the left. If so, the consequence is death.
• The women of the tribes on the left bank of the Niger River are not allowed to eat with the left, for fear of black magic.
• Japan, XX. In the early years of the 20th century it was enough to have a left wife to be able to divorce.
• And today? : Openers, Polaroid cameras, guitars, pans, saxophones, computer number keys, scissors, violins, school desks, notebooks, zippers, car changers, video cameras… are everyday limits for the left.

Curiosities and statistics

• 

  Leonardo Da Vinci (1452-1519) is one of the sages of the Renaissance. It is sufficiently demonstrated that he was a multifaceted man, since the goods of his work in painting, architecture, anatomy are well known... The Italian teacher and sage was leftist, as were other significant people over the centuries, such as Marie Curie, Newton, Michelangelo... are clear examples.
  Around 450 people live in the American city of Left Hand. They are all left.
• Most of the Kerr in Scotland were left. To fight the enemies they came to build the stairs of their castles to the left.
• The international day of the left is August 13.
• On the Internet there is a website called "The World of the Left". A story that appears in it says: "Thousands of years ago, when humans lived in small tribes, the Gudaris carried the spear on the left hand and the shield on the right. When they were going to talk to other tribes, they threw the shield to the ground and greeted the rivals with the hands of the right. In this way, if you want, you could get attacked with the greeting. The brave ones threw the spear from the left hand to the ground and fired. So the brave say goodbye with their left hand."
• 1 in 10 people is left (about 600 million people).
• 30% of the population is more skilled with the left leg.
• In the Anglo-Saxon countries there is more left than anywhere else.
• Among the twins there is much left, but it is very rare that the two twins are left.
• The probability of two right-handed parents having a left child is 0.02%; if one of them is left, the probability reaches 0.17%; and if both are left-handed, the probability increases to 0.46%.
• The left have more chances of dyslexia and stuttering, especially if they have been forced to use the right hand as a child.
• Some of the most famous left: José María García, José María Fernández García, José María García,

Published in D2 .