Because they were right-handed! Or so says this MSNBC story on handedness and language:
Frayer and his colleagues looked at these markings on the teeth of Neanderthals (from around 100,000 years ago) and their ancestors from 500,000 years ago. In both groups, most of the teeth showed more right handed scratches than left.
[ … ]
No animals other than humans show such a bias toward right-handedness. In some primates, such as chimps and gorillas, a small 5 percent shift toward the right can be seen in some studies. This is an example of brain asymmetry, where one side of the brain takes on functions that the other side doesn’t.
In addition to our special right-hand dominance, no other animals show the language abilities of humans. No one knows when Homo sapiens developed language, but many researchers believe that brain lateralization was an important part of its origin.
“This finding has important implications for the never-ending debates about the cognitive abilities of Neanderthals,” said Dean Falk, a researcher at the School for Advanced Research in Santa Fe, who wasn’t involved in the study. She told LiveScience in an email that the “findings convincingly demonstrate that language probably existed by at least half a million years ago.”
– Jennifer Welsh, “Humanity’s right-hand dominance might be more than 500,000 years old, new research indicates”, MSNBC(4/30/2011)
While it is reasonable to assume that Neanderthals could talk, some think the thesis that they “had language because they were right-handed” demonstrates a gift for extrapolation better than it does anything else. Right brain/left brain theories are far more certain in popular culture than they are in actual neuroscience:
In general, experiments have shown that the right side of the brain controls the left side of the body and many researchers believe it also dominates in such areas as spatial abilities, face recognition, visual imagery and music. The left side of the brain controls the right side of the body and is thought to dominate in language, math and logic. However, many traits are shared by both sides, and if one side is damaged the other can take over many of its functions.
Neuroscientists routinely choose only right-handed people for research areas other than handedness, so the present-day study population might lead to extrapolations to prehistoric humans that are less reliable than they at first appear.
Note: Lefty wrote this post and Ambie edited it. Righty, the only person whose opinion counts for anything, was unavoidably tied up in the administration wing.
Update: Righty’s muffled screams eventually attracted attention, and he has just been rescued. Leftie and Ambie have been placed on administrative leave, pending an investigation. Righty is off on stress leave. Until further notice, the Uncommon Descent News Desk is manned by ‘Zoid, a space alien from Planet Zongo, recently laid off by SETI. He is not required, under new anti-discrimination legislation, to disclose his number, type, or dominance of limbs, and enquiries into this matter will receive no attention. Under the circumstances, readers are urged to take all recent posts on handedness with a grain of salt. – UD news admin