Scientists have answered this question by studying the remains of the teeth of a person who lived more than a million years ago.
“Man is the king of nature” – one can agree or argue with this statement, one thing is clear: we really differ from other inhabitants of our planet. One of the striking differences is right-handedness. According to statistical studies published on scientificamerican.com, 90% of people are right-handed. But it is only recently that right-handedness is evidence of important evolutionary changes. It is surprising that this information was obtained from the study of the fossil remains of the teeth of ancient people, and not the bones of the forearm or hand.
As you know, our brain consists of two hemispheres. The left hemisphere is responsible for language, motor skills, visual-spatial perception, and the right hand. The right hemisphere is responsible for emotions, creativity and intuition. Both hemispheres of the brain are equally important for human life, but the main difference between humans and other primates is the lateralization of the brain. This term explains the functional asymmetry of the brain, when one hemisphere is somewhat more active and takes on more functions than the other.
And so, scientists asked the question: is it possible to consider that right-handedness is evidence of the lateralization of the brain? The answer lies in the tools that our ancestors used in ancient times.
The oldest tools were found in Africa, in Kenya – their age is more than three million years. Their production and use required agility and dexterity from our ancestors, which means that the left hemisphere was already more active than the right. Moreover, in all other primates, such functional asymmetry is not observed. All these facts led scientists to the idea that the preference of this or that hand is closely related to the development of the brain.
But why were teeth specifically used for the study? It’s simple. The fact is that a sufficient number of bones of the forearm or hand were not preserved, and therefore the researchers had to look for another way. The remains of the teeth turned out to be more durable – it was them that scientists studied in order to find the answer to the question posed.
How did they do it? Scratches and abrasions were found on the teeth. They were formed during the life of an ancient man. Any object that fell on the teeth of our ancestors, they, while eating, held in their hands.
The researchers decided to recreate the situation with the help of volunteers. The only difference was that the teeth of the volunteers were protected from real damage by a special mouthguard. It was on it that the characteristic scratches were formed. In the course of the experiment, it was revealed that by biting any tough food or object, a person holds this food or object in his hands. But not only holds but also pulls to the right or left, depending on the leading hand. The scratches found on the fossilized remains of teeth sloped to the right, suggesting that most ancient people were right-handed.
The earliest evidence of right-handedness can be called the fossilized remains of a jaw that once belonged to a representative of Homo Habilis, who lived in Tanzania about 1.8 million years ago.
Grooves on the teeth
With the help of special equipment, scientists not only found many scratches on the front upper teeth of our ancient ancestors, but were also able to determine that most of the scratches are inclined to the right side, which indicates that right-handedness was characteristic of most ancient people.
This study also revealed a fairly high level of intelligence development in people who lived on the planet about 1.8 million years ago. It was the development of the brain that allowed humanity to further improve its tools and language.