MOSCOW, October 20 - RIA Novosti . Ground off with one hand skilled human teeth suggested to scientists that right-handedness and left-handedness phenomenon appeared among our ancestors already 1.8 million years ago, according to a paper published in the Journal of Human Evolution.
"We believe that this finding suggests that the brain specialize in solving different problems much sooner than we think today. We previously knew that the brain have skilled people differ, and that they were more like us than . on the great apes it turns out that these similarities extend to right-handedness, which we believe is the key to understanding human evolution ", - said David Freyer (David Frayer) from the University of Kansas in Lawrence (USA).
Today, many ordinary people and scientists believe that the left and right brain are adapted for a variety of tasks - its right half is responsible for "mathematics" and logical thinking, while the left - for the oral, written language and creativity. In principle, this confirmation was found during experiments. In particular, so-called Wernicke area and the Broca's responsible for it, located in the left half of the brain.
In addition to the separation of functions, the hemisphere also differ in the degree of its influence on the whole brain and of the organism as a whole. The external manifestation of this domination of one of the halves of the brain is right-handedness and left-handedness - in the first case the "master" is the left hemisphere in the second - right.
Before the development of the right- and left-handedness was considered by anthropologists one of the key features of human development and a sign to them of speech and other complex skills that are unique to our species. On the other hand, in recent years, scientists have begun to talk about that some other mammalian species - for example, kangaroos and chimpanzees, also use predominantly one hand for food production or other tasks that has given rise to a new debate about the evolutionary significance of this particular person.
Freyer and his colleagues believe that they were able to prove the contrary, studying one of the most famous fossils of skilled people, Homo habilis, the earliest direct ancestors of humans. The remains were found in the Olduvai Gorge in 1995, and they represent one of the most well-preserved jaws of a skilled person, which is, in fact all the teeth and some bones of the upper half of the face.
poison with these remains of primitive tools were found bones and bruised by them for the first time clearly showed that ancient people could take tens of kilometers in search of a suitable "raw material" for the production of chopped and they used them for cutting food.
So tools leave marks on the teeth of Homo Habilis
Studying photographs of the jaw, the authors noticed unusual scratches that were present only on the "front" side of the right side of the teeth. Almost all of these were scratched from the top right corner of the teeth in the lower left corner, and is rarely encountered in other parts of the tooth. This unusual pattern of scratches interested Freyer, and scientists studied more scratches, making a special impression with the jaw of an epoxy resin, "increased" her several times.
As shown by their analysis, the teeth of the ancient hominid was attended by over five hundred of these recesses, left, as suggested scientists, tools. Homo habilis was holding ax in his right hand while cutting production, which he held in his mouth, and he stretched his left hand. Sometimes blows were too strong and cutting "tool" scratching their teeth, leaving them flat characteristic potholes.
According to Freyer, the presence of such scratches is a clear evidence that skilled people were "right-handed", like most modern inhabitants of the earth, and that their brain was also split into "submission" and "dominant" half. It is, as stressed by the anthropologist does not mean that Homo habilis could speak, however, according to Freyer, right-handedness and the separation of the hemispheres was the first step towards the attainment of the mind and speech.
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