ampliar imagen

CUESTIONS

26/02/2020

Theories about their causes

Genetics:

    The individual further develops his right hemisphere by inheritance.

Researchers at the University of Oxford discovered, in August 2007, that the LRRTM1 gene is crucial for a person to be left-handed.

One of the theories, quite popular last century, is that of the distribution of the organs of the human body. According to her, the fact that the liver - a large-organ organ - is housed in the right part of the abdomen while the spleen - less heavy - is in the left side causes the center of gravity of the body to move slightly to the right and I would explain that ancestors tended to lean to that side to pick up objects from the ground. This hypothesis does not explain the existence of left-handers, whose liver is also found on the right side of the abdomen. Hereditary theory, which is supported by a Canadian study

Theory

The most accepted theory about the origin of left-handedness (or left-handedness) comes from research that indicates that their (our) brains have a dominance of the right hemisphere, rather than the left as rights.

Let's do a little memory: Physically, the brain is divided into two hemispheres. According to scientists, the brain connections are "crossed" and, therefore, the right hemisphere controls the left part of the body and vice versa.

But also, the right cerebral hemisphere is attributed spatial and visual skills (for example, the ability to imagine figures and shapes inside) creativity, emotions, the ability to synthesize and artistic talent, while the cerebral hemisphere left, language, writing, analytical thinking and logic. The neurologist Exuperio Ten Tejedor, of the Spanish university hospital La Paz says that "the most common is that the left hemisphere, where the areas of language and visual recognition are, among others, is the dominant one" In the same article he tells us that " one cannot think that a left-handed brain is a photocopy of that of a right-handed person, simply with the functions reversed. It is not the mirror of a right-handed person. Left-handers do not have hemispheric dominance so marked, it is sometimes divided between the two hemispheres , sometimes the right dominates. The cast is not completely opposed to the one in the right-handed brain; the functions intermingle. And this, in case of suffering a brain injury, can be an advantage, since as the functions they are more distributed between the two hemispheres, left-handed people have fewer problems "

Language, for example, is a skill located in the left hemisphere. For a long time it was thought that the mastery of language also influenced the hands and that, therefore, in all left-handers this function was in the right hemisphere. But, in reality, this fact is only verified in a certain number of cases. Sometimes, language is governed by both hemispheres, and very often, the function of language in a left-handed person is located in the left hemisphere (3).