William Hopkins

Division of Psychobiology, Yerkes Primate Research Center, Emory University

Parallels in the Ontogeny and Phylogeny of Non-Verbal Deixis in Humans and Chimpanzees


 

Around 15 months of age, human children being to point to request and refer to objects and events in their environment.    Many believe that the development of non-verbal referential pointing sets the stage for the subsequent emergence of language.  Though previously thought to be a uniquely human adaptation, recent comparative studies in great apes have demonstrated that non-verbal referential pointing is not unique to humans.   In this talk, I present experimental data that have demonstrated that a) chimpanzees referentially point b) they alternate their gaze between the object and social referent   d) their communication is intentional d) chimpanzees repair and elaborate when communication fails e) that not all referential communication in imperative in function but some signals are declarative and f) that lateralization in the gestural communication is quite distinct from other manual actions and that this system is associated with variation in asymmetries in the homolog to Broca’s  and Wernicke’s areas of the human brain.    I further present data on the extent to which evidence of both the initiation and comprehension of referential pointing is influenced by human enculturation compared to the natural communication system of chimpanzees and the overall findings are discussed within the context evolutionary theories on the origins of language.