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Thursday, August 1, 2013

Pushing back the origins of language

Dan Dediu and Stephen Levinson of the Max Planck Institute for Psycholinguistics and Radboud University Nijmegen have an interesting idea about the origins of human language. They believe language arose at least five times as early as previously thought. In fact, their hypothesis is that Neanderthals had language capabilities similar to that of modern humans.

Most dates for the origins of human language fall between 50-100 thousand years ago (kya). The authors believe the true start of language is closer to 500 kya. This is right about when the lineages of humans and Neanderthals split.



Comparison of Modern Human and Neanderthal skulls from the Cleveland Museum of Natural History.
Photo by hairymuseummatt and DrMikeBaxter.

Here’s the timeline presented by the authors. Six million years ago (mya) our ancestors split from chimps. I’m obviously skipping some intermediate steps, but about 1.8 mya, Homo erectus dispersed from Africa across the world. However, a group of H. erectus that remained in Africa eventually evolved into H. heidelbergensis. About 500 kya, one group of H. heidelbergensis spread through Europe and evolved into Neanderthals. A second group of H. heidelbergensis stayed in Africa and, between 100-200 kya, evolved into modern humans. Some of these humans subsequently spread throughout the globe in a third dispersion wave.

The authors believe that the development of language first began before H. heidelbergensis split into humans and Neanderthals. They claim that contrary to some opinions, Neanderthals would have been capable of human speech. They would have had the anatomical structure and the respiratory control necessary for speech. They note that while chimps and humans have different hearing sensitivities, fossil evidence suggests that H. heidelbergensis had human-like sound perception, as did Neanderthals. Thus, Neanderthals would have had the physical ability to both produce and respond to human speech. The fact that Neanderthals also made complex tools, buried their dead and showed other signs of culture indicate that Neanderthals could also have met the social requirements for complex communication. Finally, Neanderthals did have the correct coding sequence for the FOXP2 gene, a gene known to be linked to language ability.

To be fair, there are reasons why scientists don’t think Neanderthals, let alone H. heidelbergensis, were capable of speech. Neanderthals did have anatomical differences that may have made speech difficult if not impossible. Many researchers do not agree with Dediu and Levinson’s analysis. Since language does not fossilize, this may be one of those questions that never gets answered.

Dediu D, & Levinson SC (2013). On the antiquity of language: the reinterpretation of Neandertal linguistic capacities and its consequences. Frontiers in psychology, 4 PMID: 23847571