Language capacities of nonhuman animals

Abstract

In the last two decades, the study of language parallels in nonhuman animals has generated considerable controversy and excitement. Many have perceived demonstrations of linguistic skills in nonhuman animals as a threat to human uniqueness, whereas others have been uncritical of claims for complex cognitive skills in animals. Two different paradigms for studying linguistic parallels have appeared. One approach teaches great apes linguistic analogues of human language using signs or arbitrary symbol systems; the other seeks to decode communicative complexity in the natural languages of nonhuman animals. This paper reviews the language analogue studies with great apes and cetaceans, examining the utility of the different methods and reviewing the animals' accomplishments. Studies of ontogeny, syntax, referential communication, audience effects, and perception of vocalizations in the natural communication of birds, squirrels, and primates are evaluated. Finally, the brain mechanisms underlying human speech and language are compared with those involved in vocal communication in nonhuman primates. Although chimpanzees and bonobos have accomplished much, they do not threaten human uniqueness with respect to speech and language. Many of the claims for language paralleles in natural communication systems of nonhuman animals are weak, and many can be interpreted without recourse to cognitive constructs. Whereas there exist many similarities between subcortical controls of language and of animal vocalizations, there are no parallels to Broca's and Wernicke's areas in monkeys. However, the critical studies have not been done.