Kanzi or can’t he?

Nonhuman animals have been successful in using a number of language abilities through a series of studies initiating from the late 1960s. However, these studies and the researchers faced intense criticism, which resulted in a vicious backlash that almost destroyed the field. In this chapter, the author will review the most frequent criticisms, any data-driven responses, and discuss the validity of each criticism. Ultimately, the findings show that nonhumans can acquire symbols through mechanisms more complex than simple association, that those symbols are referential in nature, they can use those symbols in appropriate contexts, and that their symbolic use is not explained by imitation. Some species have also been shown to use and/or comprehend rule-based ordering systems, but these stop short of true syntactical competence. Given the continuities revealed by these studies, any complete hypothesis regarding the evolution of language must incorporate these findings.