Only 10% of the world's population is left-handed. For centuries, using the left hand was frowned upon, to such an extent that the word "sinister" is used as a synonym for left (and antonym for "right-handed"). Two American researchers have just shown that the low percentage of left-handers is the result of a delicate balance struck between cooperation and competition throughout human evolution . After collecting extensive data on left- and right-handers, Daniel M. Abrams and his colleagues at the McCormick School of Engineering and Applied Science, Northwestern University (USA), have created a mathematical model that shows how the more social a species is, the larger It is the tendency to laterality , which in the case of the human being is translated by the predominance of the use of the right hand.
"The most important factor for an efficient society is cooperation; in human societies, that has made 90% of people right-handed for at least the last 5,000 years," explains Abrams, who has released the results of his study. study in The Journal of the Royal Society Interface . Cooperation, adds the researcher, favors that we all use the same hand, for example to use the same tools. However, in certain competitive sports fields (baseball, boxing, hockey, table tennis …) researchers have found the number of left-handed athletes is around 50 percent .
