Evolution of Primate Vocal‐Auditory Communication Systems 1

Abstract

One way of tracing the evolution of language is to (1) reduce language to its structural components or design‐features, (2) discover to what extent these design‐features are present in the communication of nonhuman primates, and (3) attempt to establish the brain structures that mediate linguistic behavior in man and the extent to which such structures can mediate similar behavior in nonhuman primates. It is also important to delineate those anatomical mechanisms that are prerequisites for language from those that are later adaptations. Human peculiarities of the auditory system, vocal tract, and motor system are better explained as the result of feedback from an evolving linguistic code than as necessary prerequisites for language. The abilities to engage in sequential behavior and to form nonlimbic, cross‐modal associations are more likely to be linguistic preadaptations. The faculty of immediate memory also influences communication systems by setting constraints on sequential codes. The structure of the communicative code and the behavioral capacities of the mediating organism together determine the semantic characteristics of the code. Sign systems, when classified by their semantic properties, can be closed, semiopen, open, nominal open, subject‐predicate open, and relational open. Given human limitations, a complex sequential code is necessary if the information load is to be increased.