Have you ever wondered why most of us are right-handed? Here you can find part of the answer, although, as is often the case in scientific studies, you also have a lot of new questions.
Why are most of us right-handed and not left-handed?
90% of human beings are right-handed, that is, they preferably use the right hand to write, manipulate tools and perform the activities that require the most attention.Curiously, we are the only primates that give preference to one hand over another, and some scientists believe that behind this singularity could be an explanation of as we differentiate ourselves from the rest of the primates , just over 3.3 million years ago.
Knowing since when most of us are right-handed and how affection this trend in our evolution is not so easy, if we consider that there are few fossils of nu These predecessors in which both joints have survived, and that allow comparative studies to be carried out, but researchers have managed to address this problem: through the teeth.
A group of museum researchers and Universities in Europe, Africa and North America published in the Journal of Human Evolution , in its November 2016 edition, a study entitled OH-65: the Earliest Evidence for Right-handedness in the Fossil Record (which could be translated as: “OH-65: the oldest evidence of a right hand in the fossil record”).
OH-65 is the denomination of a jaw that belonged to a Homo habilis , an ancestor of the human being who walked and manipulated tools 1.8 million years ago, in the Olduvai gorge (Tanzania), a region of the Serengeti where they have found most of the oldest remains of ancestors of homo sapiens.
Analyzing the orientation of some With marks on OH-65 teeth and by having some volunteers manipulate tools and materials similar to primitive tools with teeth (using protectors to register marks), the researchers were able to determine that the jaw owner held the material with the mouth and left hand, while working with the tool using the right hand: OH-65 was right handed.
The oldest tools were found in Kenya and are 3.3 million years ago, so Presumably, the primates from which we descend began to differentiate themselves from the others by giving more use to one hand over the other.This action could have favored changes in our brain, such as the lateralization that is, the fact that the left side of our brain controls the right part, and He left the right.The development of tools (which we know, thanks to chimpanzees, which are not a human exclusivity) was able to stimulate this specialization of the brain and prepare the way for the great evolutionary leap that has led us to the creation of objects every Once more sophisticated, and studies like this, which has involved researchers from the University of Barcelona, Kansas, New York, Rome and Johannesburg, and in which a jaw of 1.8 million years could tell us if the hominid was left-handed or right-handed.
This way of working with the tools would have favored a greater handling of the right hand for more than 3 million years, until it became part of our genetic inheritance.That is why most of us are right-handed and not left-handed.
It should be noted that this theory does not have unanimity , and its implications are still being discussed.What do you think? Which came first, the right hand, or the lateralization of the brain? Perhaps the answer to this question remains buried in the sheets of the Serengeti.
Know why we are left-handed or right-handed.
Images: Walt Jabsco, Ashley Van Haeften, Ben Sutherland
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