The language-like behavior of Lana chimpanzee: Is it merely discrimination and paired-associate learning?

The productions of Lana chimpanzee during an experiment that lasted 25 days were analyzed from a “stock sentence” approach and from a phrase-structure approach. In answering questions posed by the experimenter and in making requests, Lana’s productions seemed to be best explained in the phrase-structure approach, in which phrases, rather than individual lexigrams, served as lexical units. Phrases were transposed, both correctly and incorrectly, and were combined to convey different meanings. Thus, it was concluded that Lana’s productions require a more complex model than the simple discrimination learning model suggested by Thompson and Church (1980).