Terrence Deacon on language evolution

December 20, 2011

Was it William Burroughs who first described language as a virus from outer space? I’ve always liked the analogy, though it may be more useful to think of language as a symbiont from inner space.

In his book The Symbolic Species (1997), Terrence Deacon describes the language-as-a-virus metaphor as extreme but helpful. He identifies the most basic principle guiding the design of languages to be ‘not communicative utility but reproduction – theirs and ours’.

Deacon feels the best way to study language structure is to do so from an evolutionary point of view. Languages have co-evolved with their hosts – us – under the forces of selection. This can help us make sense of children’s precocious rate of linguistic development:

The structure of a language is under intense selection because in its reproduction from generation to generation, it must pass through a narrow bottleneck: children’s minds. Language operations that can be learned quickly and easily by children will tend to get passed on to the next generation more effectively and more intact than those that are difficult to learn. . . . Language structures that are poorly adapted to this niche simply will not persist for long.

As language emerged in tandem with the human nervous system – each adapting to the other – it drew on existing cognitive abilities. The facility for language is not the responsibility of some dedicated device in the brain but rather is spread across many parts of it.

In his his article ‘Rethinking the natural selection of human language’, Deacon writes that

the neural structures and circuits involved in the production and comprehension of language are homologous to structures found ubiquitously in most monkey and ape brains: old structures performing unprecedented new tricks.

Below is a video of Deacon giving a talk in 2010 called ‘Language & complexity: Evolution inside out’. It’s quite a technical presentation (I was grateful for my distant background in genetics and developmental biology), but Deacon is a clear and engaging speaker and his subject matter is deeply interesting.

Replicated Typo, reporting on the talk, says Deacon’s ideas are ‘our best avenue for exploring how language evolved’. Edmund Blair Bolles at Babel’s Dawn is similarly impressed; he writes that the strength of Deacon’s proposal is that it “[describes] a mechanism for the brain changes that support language”:

The old view that language functions are confined to a few regions like Broca’s area and Wernicke’s area, or even the left hemisphere can no longer stand. Language processing involves complex coordination between multiple systems. But the modern human brain is a relatively recent acquisition. How did all that complexity evolve and become coordinated?

Deacon has some persuasive thoughts on this. Birdsong, some of you will be happy to hear, features quite a lot. The talk lasts about an hour, with a short Q&A at the end.