Righties prevailed in prehistoric era

U. KANSAS (US) — A study of markings on fossilized front teeth show that right-handedness dominated as long as 500,000 years ago.

“The patterns seen on the fossil teeth are directly and consistently produced by right or left hand manipulation in experimental work,” says David Frayer, professor of anthropology at the University of Kansas.

The oldest teeth come from a more than 500,000-year-old chamber known as Sima de los Huesos near Burgos, Spain, that contains the remains of humans believed to be ancestors of European Neandertals. Other teeth studied by Frayer come from later Neandertal populations in Europe.

The research is reported in the journal Laterality.

“These marks were produced when a stone tool was accidentally dragged across the labial face in an activity performed at the front of the mouth,” says Frayer. “The heavy scoring on some of the teeth indicates the marks were produced over the lifetime of the individual and are not the result of a single cutting episode.”

Overall, right-handedness was found in 93.1 percent of individuals sampled from the Sima de los Huesos and European Neandertal sites.

“It is difficult to interpret these fossil data in any way other than that laterality was established early in European fossil record and continued through the Neandertals,” Frayer says. “This establishes that handedness is found in more than just recent Homo sapiens.”

The findings on right-handedness have implications for understanding the language capacity of ancient populations, because language is primarily located on the left side of the brain, which controls the right side of the body.

“The general correlation between handedness and brain laterality shows that human brains were lateralized in a “modern” way by at least half a million years ago and the pattern has not changed since then,” Frayer says.

“There is no reason to suspect this pattern does not extend deeper into the past and that language has ancient, not recent, roots.”

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