In a thought-provoking perspective published in Science on May 24, Fisher and Ridley seek to challenge the idea that key genetic changes were prerequisites to advanced communication, cultural development, and the evolution of modern humans. The model they put forward is one where cultural changes provide the selective environment for enhancing genetic mutations.
As examples the authors cite lactase-persistence and alcohol tolerance as genetic mutations that likely followed increased dairy and alcohol consumption in Europeans. The main thrust of their argument as it relates to language is as follows:
Under the culture-driven view, many critical genomic alterations that facilitated spoken language, for example, might have spread through our ancestors after this trait emerged. That is, prior behavioral changes of the species provide a permissive environment in which the functionally relevant genomic changes accumulate. The selective advantage of a genetic change that increased language proficiency would likely be greatest in a population that was already using language.
The authors conclude with a statement about how easy it is to confuse cause and effect in science. This statement applies well beyond the confines of science.
I think the main point of this article is logical, although other scenarios that do not require cultural progress to precede genetic changes are similarly plausible. Good thought-provoking perspective, but assuming cultural changes always precede reinforcing genetic changes is a tenuous position.
To the credit of the authors they do not promote an all-or-nothing viewpoint, rather they suggest an intertwining of cultural and genetic changes.