1.8 Million-Year-Old Teeth Show Earliest Evidence Of Right-Handedness

Posted: Oct 21 2016, 7:07am CDT | by , in News | Latest Science News

 

1.8 Million-Year-Old Teeth Show Earliest Evidence of Right-Handedness
David Frayer, KU professor emeritus of anthropology, is lead author on a recent study published in the Journal of Evolution that found striations on teeth of a Homo habilis fossil 1.8 million years old moved from left to right, indicating the earliest evidence in the fossil record for right-handedness. Researchers believe the marks came from using a tool to try to cut food being pulled from the mouth with the left hand. Credit: David Frayer
  • World's oldest rightie dates back much further than we thought
 

The fossil record showed early signs of the appearance of right-handedness in man.

Let’s face it. The world is biased towards lefties. From the side on which door knobs are situated all the way to the shower at the side of the water closet, everything conforms to the right-handed majority.

Lefties are a creative lot though. However, the prejudice humanity has against lefties goes far back in prehistory than was previously thought. Striations on the teeth of a Homo habilis fossil found the earliest evidence of right-handedness.  

This went back 1.8 million years into the mists of the past. That tells us a lot about the lateralization of the brain. Homo habilis had lateralization of the brain and was probably closer to modern humans than its ape ancestors.

This fact goes all the way to the handedness of this species of early man. The findings were published online this week in the prestigious Journal of Human Evolution.

After a thorough analysis of tiny cut marks or labial striations on an upper jaw fossil, this fact was ratified with unanimity by the research team. The fossil had been unearthed from the Olduvai Gorge in Tanzania. 

The network of deep striations showed that most of the cut marks slid towards the southern right side. This form of early man must have used a tool with its right hand to butcher its prey while it was in its mouth. It was pulling it apart with its left hand.

The scratches are clearly visible to the unaided eye. However, a microscope was employed to pinpoint the alignment and angles in this ancient handedness equation.

The scratches were apparently the result of a stone tool which was employed to tear material which was then crushed between the anterior teeth. This tool damaged the teeth too thereby leaving marks on its surface.  

The handedness factor and language are both connected. They seem to have genetic components which belong to different systems. Yet the link remains since both are products of the left side of the brain.

While a single fossil of a Homo habilis is not enough to prove the causality, as more evidence is uncovered of early man, there will be a meeting point of right-handedness, cortical re-assembly and the language instinct.

All these things began early on in the origins of our species. Today 90% of mankind is right-handed. This is a vast improvement over apes which have a 50:50 ratio in such matters. Brain lateralization seems to be responsible for this handedness lottery of sorts.

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