Sep 14

Why are lefties left-handed?

Why are lefties lefty?Why are lefties left-handed? It is an innate or acquired characteristic? It manifests in these cases, brain areas unexplored by righties? Why are fewer left-handed than right-handed? Here are a series of questions that, naturally, they put themselves, lefties and others.

Most people are not right-handed or left-handed entirely, but ambidextrous. Many use the right hand to write, but can easily lead weights or to perform various activities with his left hand or vice versa. Some can be lefty when playing tennis, but righty when playing handball and basketball. There are few people who use both hands for everything they do. In the world lefties represent about 13% of the total population.

Lateralization is the particularity of the human brain that requires each of the two cerebral hemispheres have certain ” powers “, although obviously the two can only work together. Tgus, the left hemisphere is responsible for language, analysis, logic and computation, and the right with space orientation , face recognition, artistic capabilities. The right hemisphere controls the left side of the body, and the left side controls the right.

Therefore, in lefties case, the right hemisphere has dominant role. And once your brain is used to work in a certain manner, the tendency is to keep the respectively ” custom ” . For example, 97% of right-handed language is controlled by the left hemisphere, while this is true only for 60% of left-handed. Experts in the field believe that for lefties the brain is less lateralizat, the two cerebral hemispheres communicating more than the others.

Systematic scientific observations led to the conclusion that such a characteristic is rather a predisposition, which would indicate genetic origin, but found that most of the time, left-handedparents have right-handed children, or even relevant, true twins ( homozygous ) haven’t always the same hand preference. However, you can know before birth if a child will be lefty or righty. Such a ” diagnosis ” is possible in the 29th week of pregnancy, the fetus reaction is noticeable to various stimuli.

In 2007, a team of researchers just announced that it has discovered a gene ( PCSK6 ), which is related to the phenomenon of lateralization of the brain and, therefore, determine whether a person is right-handed or left-handed. Suppression of this gene has dramatic effects, the embryo developing completely asymmetric. However, doctors could not say with certainty who or how many genes are involved in the print of predisposition that a person to be lefty.

It is also known that there are more lefty men than lefty women, hence dragging the conclusion that testosterone ( male hormone ) also has an important role. High level of testosterone promotes the development of right hemisphere dominance in left-handed. On the other hand, it seems that at a mature age, testosterone level in left-handed decreases, which makes them less ” aggressive ” than the others. And sociological factors may have some influence, lefty men proving to be more independent, original and creative, while lefty women have tendencies towards a certain meticulousity in what they do and more efficienty in repeatable activities.

Some features exist in the way the lefties represent the spatial cues, some visualizing them as right-handed would watch them in a mirror: the direction and rotation, for example, are seen reversed, so it takes some more time for lefties to retain in what sense to tight a screw, valve, etc..

Even curently it can not be said why the lefties are fewer than righties. There are many theories, some claiming that the phenomenon is related to brain development in the embryonic stage or the fetus position in the uterus, this influencing the brain lateralization.

The fact is that they are atributed a number of qualities to lefties observed in time attributed to the fact that they use capabilities of the brain that remain latent in righties. Lefties seem to be more creative, have artistic predispositions, better reflexes, they can harness intelligence in complex ways, etc.. Lefties were, for example, Leonardo da Vinci, Michelangelo, Julius Caesar, Marie Curie, Albert Einstein, Charlie Chaplin, and in more recent times, Bill Gates, Bill Clinton, Barack Obama, etc..

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