The main point of this article was to show the uniqueness of human intelligence. In doing this, David Premack compared and contrasted humans to chimpanzees and monkeys. They were compared on the basis of different aspects that underlie the evolution of language; voluntary control of the voice, face, and hands, imitation, teaching, theory of mind (recursive/nonrecursive), and the capacity to acquire recursive and/or nonrecursive grammar. Humans have obtained six symbol systems: two that have evolved which are the genetic code and spoken word and four that were invented which are written language, Arabic numerals, music notation and Labanotation. It is safe to say that the grammar of human language is definitely unique.
To begin with, he talked about voluntary control of the sensory-motor systems. There has been evidence that shows that chimpanzees do not show voluntary vocalization but they do have voluntary control of their hands which allows them to sign to one another. However sign language depends on the face as well as the hands. Facial expression plays a linguistic role in signing. Signers process emotional facial expression in the right hemisphere and linguistic facial expression in the left hemisphere. This means that chimpanzees could not have evolved a language that is either speech or sign.
Second is the perspective of the first and second levels of imitation. The first level of imitation is the ability to copy the object chosen by a role model. But with the second level of imitation the individual copies the models motor action. Most species cannot complete the second level of imitation including monkeys, but chimpanzees have the ability to do this with the exception of human training. Imitation is paired with teaching, in which imitation produces a rough copy of the information while teaching smoothens it out. This process is only seen in humans.
Recursion makes it possible for the words in a sentence to be widely separated and yet dependent...