Primate Vocal Communication and the Evolution of Speech

Studies of nonhuman primate communication are often motivated by the desire to shed light on the evolution of speech. In contrast to human speech, the vocal repertoires of nonhuman primates are evolutionarily highly conserved. Within species-specific constraints, calls may vary in relation to the internal state of the caller or social experience. Receivers can use signalers’ calls to predict upcoming events or behavioral dispositions. Yet nonhuman primates do not appear to express or comprehend communicative or informative intent. Signalers are sensitive to the relation between their own actions and receivers’ responses, and thus, signaling behavior can be conceived as goal directed. Receivers’ ability to integrate information from multiple sources renders the system flexible and powerful. Researchers who take a linguistic or biological perspective on nonhuman primate communication should be aware of the strengths and limitations of their approaches. Both benefit from a focus on the mechanisms that underpin signaling and responses to signals.