Homo sapiens are unique in the animal kingdom in having an overwhelming propensity to right-handedness, by a margin of nine to one. The lateralization of the brain that causes the dominance of one side of the body has been the subject of intense interest by researchers, with most hypotheses revolving around the development of language in the left brain, whose dominance would then extend to the right side of the body it controlled.
While much of the evidence is still scanty, new fossils reinforce the right-handed dominance theory and suggest an origin of language development that's much earlier than previously thought.
Fossil Teeth and Tool Use
Scientists theorized that studying the teeth of several types of ancient humans (including 100,000-year-old Neanderthals and 500,000 year-old Neanderthal ancestors) could give clues as to whether ancient humans were as overwhelmingly right-handed as is the case with modern humans.
When ancient humans processed hides, it is thought that they held one end in the hand and one end in the mouth, and then scraped the hide with a tool held in the dominant hand. By studying the pattern of scratches left on the front teeth by accidental contact with the stone tool, scientists could determine which hand was holding the tool. And in 93 percent of the teeth studied, scratch marks indicated the ancient humans were using their right hands to hold the tools.
Left Brain Language Development
Since right-handedness is unique to humans, researchers posit a link between right-hand dominance and another trait not seen in other animals: language. The complex language developed by humans is largely centered in the left hemisphere of the brain, and since the left side of the brain controls the right side of the body, it would seem to indicate that as language evolved in the left side of the brain, the right side of the body began to dominate in most humans.
Ancient Language Origins
If the theory is correct, it would indicate that humans were using complex language more than half a million years ago, quite a bit earlier than previously theorized. This finding also suggests that Neanderthals, unlike their portrayal in popular culture, likely spoke as eloquently as any modern human.
Sources:
- Lynch, Brendan M. "New Research Suggests Right-handedness Prevailed 500,000 Years Ago - KU News." Home - KU News. 18 Apr. 2011. Web. 03 May 2011.
- Welsh, Jennifer. "Ancient Humans Were Mostly Right-Handed, Too." LiveScience. 29 Apr. 2011. Web. 03 May 2011.
Jenny Ashford - Jenny Ashford is a writer and graphic artist from central Florida. Her main area of interest in her Suite 101 articles is science, with a ...
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