Irene Pepperberg challenges the idea that the capacity for language and abstract thought is unique to primates. “If one starts with a brain of a certain complexity and gives it enough social and ecological support, that brain will develop at least the building blocks of a complex communication system.”

THAT DAMN BIRD: A Talk with Irene Pepperberg provides an entertaining and thought-provoking review of her grey parrot studies and related research. I found particularly interesting a discussion of how playing with toys in physical space relates to the development of language. This has been studied in human children, chimpanzees, and grey parrots.

In the 1970s, [Patricia] Greenfield looked at young children and found that at the time they start serially and hierarchically stacking toys like cups and rings in perfect order, they also start combining their labels in somewhat regular syntactic patterns; that is, they begin to produce phrases like “Want cookie,” or “Want more milk.”

Greenfield argued at the time that these capabilities were unique to humans. Since then similar behavior has been observed in other primates and in grey parrots. It struck me as surprising, yet obvious, that both words and actions are reflective of abstract thought. Play is gestural language.