Greg Laden's blog has just posed the following talk by Mark Pagel under the title "How language transformed humanity"
I am very interested in the way that language suddenly appeared on the scene, and the accelerating speed at which it has helped to transform the world in which we live. While Mark clearly recognizes the importance of cultural factors I was not happy with some of his supposed facts - and while I think that the concept of "social learning" can be useful in discussing the cultural explosion that coincides with, and is possibly driven by, the appearance of language I was not always happy with some of his examples. As a result I published the following comment on Greg Laden's blog.
Oh Dear - he really runs down the capability of our ape and early human relatives and misses the significance of fact that many of the areas where there are many languages with few speakers involve primitive societies.
I would agree that once language reaches a certain tipping point it greatly facilitates the transfer of information between generations - and also motivates further cultural development of the language itself. Basically you get what in chemistry I would call an auto-catalytic reaction. Once the tipping point is reached the each development in language skills makes further development easier - and there is an accelerating chain reaction. This will not only affect language - but also all the cultural activities and objects of the time.
The question which he does not address is what came before "language" which he does not really define, except by a crude analogy. Once the human line split off there has been a steady increase in brain size and almost certainly vocal abilities - and the majority of these changes will have been before "language" evolved.
What were the evolutionary pressures to drive these "improvements" if "language" did not exist. Humans were hunting on the African plains and needed skill and good team working to catch and kill larger animals. For instance in setting an ambush those lying in wait need to alert the drivers that they are ready. What better than sound - but if the sound is obviously human the prey will evolve to treat obviously human utterances as a danger - so what could be better than to evolve the ability to mimic other animals such as an owl hooting, etc., and to make a wide range of clicks, whistles and yodels, and to be able to change pitch
Before a proper language had developed there could well have been a simple hunting symbolic language which would involve a very wide range of phonemes - and each hunting group might use them in different way because they were hunting different prey in different environments. Recent research on attempting to date the development of language in Africa start with the assumption that the more primitive languages use a larger number of phonemes. Such an origin might also explain that the majority of languages with very small numbers of speakers involve tribes which are either still hunter gathers or were so until comparatively recent times.
Where did the tipping point come. My own guess is around the camp fire of an evening, when the hunters returned - and started to use their hunting calls to tell the story of the day. Children would learn about the methods and dangers of hunting without being exposed to them - thus acquiring a wider range of hunting skills. Once language reaches the stage of "Tell about the time you killed the lion, Daddy" the art of story telling has got underway. Legends are born and those of the Australian Aborigines go back several tens of thousands of years to the Dream Time, when some now extinct animals were alive.
An interesting feature of this model of language development is that language starts from a cultural tipping point and there may be no simple genetic factor at all. OK - more brain capacity could help handling far more concepts - and better vocal skills might make it easier - but the fact that the more advanced languages use less phonemes would suggest that a wide range of vocal skills is not essential for language.