Home Science Why are there less left-handed than right-handed?

Why are there less left-handed than right-handed?

Why are there less left-handed than right-handed?

The dominant side of a person depends on genetics and the environment, although competition with others favors the use of the left hand

About 10% of the world population are left-handed, like Leonardo Da Vinci, Beethoven or Einstein. It’s more common in men than women and they even celebrate International Lefty Day every August 13th. But why are there so few?

There are several scientific studies that have tried to find out more about this subject. For example, Daniel Abrams from Northwestern University, in the United States, created a mathematical model which showed that the more social a species, the more it tends to lean to the side.

Abrams said that the most important factor for an efficient society is cooperation, and in human societies that has made 90% of people right-handed in the last 5,000 years. However, competition favors the use of the left hand, this is what happens with athletes who reach 50% of the left hand.

Are left-handers born or are they made?

A team of scientists from the University of Oxford, England, found that genetic instructions in human DNA are related to being left-handed.. With a complete genetic code database of around 400,000 Britons, just over 38,000 were left-handed.

One of the authors, Gwenaëlle Douaud, confirmed that they had discovered four critical mutations and, for the first time, it was known that using one hand or the other had a genetic component.

The researchers also noted that left-handed people may have better verbal skills because the language areas in the left and right sides of the brain communicate in a more coordinated way, although this study doesn’t fully prove this. In addition, left-handed people also had a slight risk of suffering from schizophrenia or Parkinson’s.

“In many cultures, being left-handed is considered unhappy or malicious and that is reflected in language. If you look at the French language, gauche means left and strange. With English, right what is right, they use the expression being right, which means to be right. What this study shows is that being left-handed is just a consequence of the biology of brain development, it has nothing to do with luck or malice,” he explained. Dominic Furniss, another of the authors of the report.

The results of the study indicated that a person’s dominant side depends 25% on genetics and 75% on the environment. Therefore, identical twins with the same genes do not need to have the same dominant hand.

Left-handers are also made. The case of tennis player Rafa Nadal is curious because, although he is right-handed, he used his left arm from a very young age by indication, since that way he hit the ball better.

Therefore, research has shown that left-hand use is a consequence of brain development and genetic interaction. Left-handers were not well regarded for many centuries and some had to use the right hand, which was a problem for their development. Fortunately, left-handed people can be left-handed today.

REFERENCES

A model that balances cooperation and competition may explain our right-handed world and the dominance of left-handed athletes

Dexterity, language areas and neuropsychiatric diseases: perceptions from brain imaging and genetics

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