Referential signaling in non-human primates:: Cognitive precursors and limitations for the evolution of language

Recent evidence suggests that our hominid ancestors did not have speech until very recently, indicating that many of the cognitive skills required for linguistic competence must have been present in the primate lineage long before the advent of language. These pre-adaptations might have evolved to function in communication as part of a general social or ecological intelligence, or as mere byproducts of other traits, calling for an empirical investigation of the functional significance of these abilities. The natural referential and combinatorial capacities in extant primates in their natural habitats are of particular interest. The empirical evidence reviewed in this chapter suggests that various cognitive capacities required for understanding language, including the ability to take into account semantic, syntactic, and pragmatic cues, are present in non-human primates. As signalers, however, non-human primates are curiously limited, showing little evidence of cognitive flexibility and creativity. These expressive limitations seem to be rooted in at least two deficiencies: a lack of sophisticated control over the articulators in the supra-laryngeal vocal tract and a remarkable shortcoming in social cognition. Non-human primates have consistently failed to show evidence of perceiving others as beings that possess mental states, such as beliefs or desires, suggesting that mind-blindness has impeded the evolution of sophisticated communication in situations that go beyond evolutionarily urgent events. © 2003 Elsevier Inc. All rights reserved.