Could you perhaps elaborate on the apes part? Or rather how the difference between the "instinct to trade" and "language" ended up being distinguished as such? I somehow think of the two as being extremely inter-related, language (in its rudimentary form, not the advanced language of humans that humans such as Orson Scott Card use) would probably be used in all ways to obtain a sort of 'comparative advantage', as opposed to a species that doesn't use language. It is in essence a tool used to obtain/give aid, and I cant think of another purpose why it would evolve suo moto.

Therefore, I may want to take issue with Ridley's claim that apes were "taught Language"(it sounds to me like they were thought words and corresponding actions or the rough equivalent of that). Nevertheless, it is an interesting theory and I would like to know more.