Human apes: human use and understanding of great ape gesture

All great apes, including humans, employ a rich repertoire of vocalizations, facial expressions, and gestures to communicate. Great ape gestural repertoires are particularly elaborate, with chimpanzees and bonobos employing over 80 different gesture types intentionally: that is towards a recipient and with a specific goal in mind. African great apes, that is chimpanzees, bonobos, and gorillas, share almost 80% of their gestural repertoires; but what happened to this gestural inheritance in the human lineage? In biological terms chimpanzees and bonobos are more closely related to us than they are to a gorilla. I will discuss two new approaches to this question that employ ape field methods to exploring human behaviour. With focal follows of young early-verbal children we show that production of a substantial proportion of the 'ape' repertoire in human infants, and with play-back of ape behaviour to human adults, we show that comprehension of the ape repertoire appears to have been retained, even in fully language-using individuals. I will discuss the implications of this for comparisons of communication across ape species, and for our understanding of the evolution of human language.