Michael Tomasello

               Why Don't Apes Point?

Each of the great apes species has a rich and varied repertoire of
communicative gestures.  But virtually all of these gestures are dyadic
- concerning the immediate social interaction of sender and receiver -
and imperative - concerning things the sender wants the receiver to do. 
In contrast, from before language begins human infants communicate
triadically about external objects and events, and they do so for both
declarative and informative motives, that is, in order to share
attention or information with another.  Soon after that they begin to
communicate with conventional linguistic symbols, whose bi-directional
nature is specially built for sharing and collaboration.  This
comparison between apes and prelinguistic and just-linguistic human
infants suggests that a crucial component in the evolution of human
linguistic communication is the motive and capacity for sharing
experience and getting things done collaboratively.