Nonlinguistic Communication

Nonlinguistic communication—communication without language—must have been important to early hominins, as it is in baboons and most other animals. This may have been especially true when hominins expanded their distribution to include more diverse habitats with larger savanna components and needed more cooperation to deal with new or exacerbated problems. Baboons illustrate forms of communication that could have been effective in these circumstances. Baboon vocal systems are evolutionarily conservative in their basic content, but show considerable flexibility in their use. Two forms of vocalization that are similar between baboons and humans, barks and grunts, appear in diverse social interactions. The implication is that even the earliest hominins could have had a highly adaptable vocal system. Baboons also display some unusual tactile signals, such as touching another’s genitals, that also appear in greeting behaviors of some human societies. Recent research has reported leave-taking as another baboon social communication. Captive study suggests a considerable capacity for visual signals. Sequence organization, a theory of human communication that views each signal as making the response relevant, can be applied to baboon interactions. Some baboon communication may be referential, that is, specifying an external object.