Mark Pagel

Each of you possesses the most powerful, dangerous and subversive trait that natural selection has ever devised. It's a piece of neural audio technology for rewiring other people's minds. I'm talking about your language.

I think the driving force for cultural evolution is this desire for groups to be splitting off and separating and forming subgroups insofar as the environment will allow it. We see great cultural diversity and large numbers of cultures per unit area in regions of the world in which the environment is really rich.