Four studies revealed that a 2(1/2)-year-old chimpanzee (Pan), after 6 months of computer-controlled language training, proficiently reads projected word-characters that constitute the beginnings of sentences and, in accordance with their meanings and serial order, either finishes the sentences for reward or rejects them.

A computer-controlled language training system was designed and constructed to enhance the objectivity and efficiency of inquiry into the language-relevant behaviors of apes. The system allows the S to gain control over the events of the 24-h day in direct correspondence with its competence in using a keyboard on which each key represents a word. Various incentives can be obtained through the selection and depression of appropriate keys in accordance with rules of sentence structure monitored by a computer. The system is flexible and allows for eventual conversation between man and ape, with the computer as the intermediary. A Teletype records all that transpires. Achievements of the chimpanzee S over the course of the first 8 months of the system's operation attest to the worth of the system and training methods.The capacity of true, productive language has long been held by many professionals and laymen as uniquely human, but the recent studies by Gardner and Gardner (1971) and by Premack (1971) give reason to question this view. These investigators have demonstrated that the chimpanzee (Pan) can acquire behaviors that suggest the mastery of a vocabulary and at least a circumscribed ability to use these words in novel chains apparently appropriate to newly encountered test and living situations. The capacity of the chimpanzee for mastery of rules of sentence structure, however, remains in question, for this was not the primary line of inquiry in either of these studies.All studies have their limitations, and the ones referred to above are not without theirs. Their pioneering and creative qualities are commendable, but their methods and scope leave unanswered two questions of primary importance: (a) Do apes have the capacity

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