WASN'T IT THE OBELISK?

Look who was talking: We began talking as early as 2.5m years ago, writes Stephen Oppenheimer. Is that what drove the growth of our brains? (Stephen Oppenheimer, August 7, 2003, The Guardian)

An alternative to the Chomskian theory, is that language developed as a series of inventions. This was first suggested by the 18th-century philosopher Etienne Bonnot de Condillac. He argued that spoken language had developed out of gesture language (langage d'action) and that both were inventions arising initially from the simple association between action and object. The Condillac view, with some development, can be traced to the present day with the recent work of New Zealand psychologist Michael Corballis and others. The theory sees gesture language as arising originally among apes as sounds accompanying gestures, with these sounds gradually becoming coded into "words" as the new skill drove its own evolution. Subsequently, coded words developed into deliberate, complex communication. Evolutionary pressures promoted the development of an anatomy geared to speech - the larynx, vocal muscles and a specific part of the brain immediately next to that responsible for gestures.

This view, that spoken language was ultimately a cultural invention like tool-making, which then drove the biological evolution of the brain and vocal apparatus, seems obvious when you think of the development of different languages. [...]

So we have the paradox that over the period when our brain was growing most rapidly, our material cultural development, as measured by stone tools, advanced only marginally; then, over a million years later, when the culture of anatomically modern humans finally started to accelerate, artistically and technologically, our brains were actually getting smaller.

The additional piece of evidence that makes this paradox all the more significant is that brain size did not just leap between human species in a direct line of ascent towards ourselves. Over the period from 2.5 to 1.5m years ago, it turns out brains were growing more rapidly than at any time since, within all the different human species and also in Paranthropus species. The logical conclusion is that there must have been a unique new behaviour driving brain growth, shared between all species of humans and Paranthropus, with its origin, presumably, in their immediate shared walking ape ancestor.

So, what was driving rapid brain growth right at the beginning 2.5m years ago? The answer may have been staring us in the face. Namely, that not only were early humans and Paranthropus communicating but their ancestor, a walking ape, had started the trend in this very useful skill. Around 2.5m years ago the weather took a decided turn for the worse, becoming more variable and colder and dryer. The search for food became more taxing, and there would have been a real need to communicate more effectively and cope with the worsening environment in a cooperative way.

Speech, a complex system of oral communication, is the only inherited primate skill that would self-evidently benefit from a larger computer than that of a chimp. The near maximum in brain size achieved by 1.2m years ago indicates that those early ancestors could already have been talking perfectly well. It was all over bar the shouting. Our new Rolls Royce brain, developed to manipulate and organise complex symbolic aspects of speech internally, could now be turned to a variety of other tasks.

Of course, one wonders then why only one of the primates developed this capacity, given that all would have benefited equally. But that's the nature of determinism. Posted by Orrin Judd at August 18, 2003 10:09 AM