Ape Language Research Research Articles

Kanzi: A new beginning

Ape language research has been marked by constantly shifting demands made by those who feel that only human beings can acquire language. Kako (1999) continues in this tradition, but his paper marks a significant shift. For Kako concedes that Kanzi possesses rudimentary syntactic skills; but he questions whether Kanzi possesses morphosyntax. Rather than searching, yet again, for some linguistic element that Kanzi has not mastered, we feel it would be more productive, for reasons we explore, to focus now on what exactly Kanzi can do and how this came about.

Symbol Comprehension and Learning

Language comprehension in the great apes has been investigated through a variety of paradigms. This experiment employed a match-to-sample computer task to investigate the current language comprehension of three chimpanzees (Pan troglodytes) raised in different language environments but with a similar symbol system (lexigrams). Each of these animals still uses the lexigram keyboard system on a daily basis but none of the animals are the focus of ongoing ape language research programs. Six testing conditions were employed utilizing photographs, lexigrams and spoken English. The results indicated that all apes retained knowledge of at least some of the symbols that they had previously learned, and they each learned differing numbers of new lexigrams that were never taught to them. This indicates that rearing history is important not only in initial symbol acquisition in apes, but also in extended recall of the symbols, particularly when those symbols are used infrequently later in life. Differences in the current ages of these apes requires that such a conclusion be made tentatively, and suggests the need to continue the examination of symbol vocabulary size at various times throughout the life of each ape.

Ape Language Research: A Review and Behavioral Perspective

The ape language research of the Gardners, Fouts, Terrace, Rumbaugh, and Savage-Rumbaugh is reviewed. This research involved the raising of chimpanzees (and a bonobo) in human-like environments over extended time periods. The results indicate that apes are capable of learning small verbal repertoires in a fashion similar to that of human infants. The writings of the ape language researchers show an opposition to behavioral approaches to language. Although they characterize each other's work as behavioral, they oppose such explanations applied to their own work. A behavior-analytic approach to language has much empirical support, and behavioral treatments for people with language delays have produced substantial results. Despite the protestations of the ape language researchers, now is an appropriate time to apply the extensive knowledge base derived from a science of behavior to language acquisition in apes.

VERBAL BEHAVIOR

THE RECENT HISTORY AND CURRENT STATUS OF THE AREA OF VERBAL BEHAVIOR ARE CONSIDERED IN TERMS OF THREE MAJOR THEMATIC LINES: the operant conditioning of adult verbal behavior, learning to be an effective speaker and listener, and developments directly related to Skinner's Verbal Behavior. Other topics not directly related to the main themes are also considered: the work of Kurt Salzinger, ape-language research, and human operant research related to rule-governed behavior.

Vocal stimulation early in life and infant vocal responsiveness to mother vs. stranger: A curvilinear relationship

Ape language research presents us with a worthy and successful example of realist bootstrapping of theorizing and experimentation. In the 1940s, the Hayeses set out without a definition of language, merely taking it that it appeared in the normal maturation of the normal human in normal circumstances and so might appear in a chimpanzee similarly placed. The Gardeners, noting the chimpanzee's limited vocalizing apparatus, tried to show that a chimpanzee would develop language in the same way as the human child if only the language were a sign language. Meshing with research by Premack and Terrace, recent work on fluent human signers of American Sign Language has shown that while chimpanzees can be led to use a gestural pidgin-vocabulary to manipulate and socialize, they in no way develop linguistically as the human infant signer does. In terms of homology, a case can be made that the signing chimpanzees have little improved on the Hayeses' chimpanzee, who eventually vocalized five English words. What this stretch of interaction between theory and experiment bears out is the autonomy of the formal linguistic apparatus from other conceptual and perceptual capacities that we undoubtedly share with our primate cogeners.

VERBAL BEHAVIOR AT A PROCEDURAL LEVEL IN THE CHIMPANZEE

Ape language research has typically employed cognitive descriptions of ape competencies. Recently, Epstein, Lanza, and Skinner (1980) attempted to simulate some of the ape findings with pigeons. They also used cognitive terms to describe their results, but with "tongue-in-cheek." In the hope of bringing about a better understanding of the ape research, this paper describes the main aspects of one ape language project, using a behavior-analytic framework. It then briefly compares and contrasts, from that perspective, the training programs used with pigeons and with apes. It is concluded that the behavior-analytic framework, and the procedures devised to produce language skills in apes, provide strong support for several of the major positions set forth in Skinner's (1957) Verbal Behavior.

The vindication of the language organ

Ape language research presents us with a worthy and successful example of realist bootstrapping of theorizing and experimentation. In the 1940s, the Hayeses set out without a definition of language, merely taking it that it appeared in the normal maturation of the normal human in normal circumstances and so might appear in a chimpanzee similarly placed. The Gardeners, noting the chimpanzee's limited vocalizing apparatus, tried to show that a chimpanzee would develop language in the same way as the human child if only the language were a sign language. Meshing with research by Premack and Terrace, recent work on fluent human signers of American Sign Language has shown that while chimpanzees can be led to use a gestural pidgin-vocabulary to manipulate and socialize, they in no way develop linguistically as the human infant signer does. In terms of homology, a case can be made that the signing chimpanzees have little improved on the Hayeses' chimpanzee, who eventually vocalized five English words. What this stretch of interaction between theory and experiment bears out is the autonomy of the formal linguistic apparatus from other conceptual and perceptual capacities that we undoubtedly share with our primate cogeners.

Chimpanzee language research: Status and potential

The impact of ape-language research upon current thought pertaining to language and man in relationship to the apes is discussed within an evolutionary framework. Studies of apes can reveal certain requisites to the language skills of humans. Social adaptations are thought to be important to the evolution of those requisites. A review of ape-language research is made, with emphasis given to the problems of controls where work is doneen face with the subjects, as where Ameslan (signing) is the system employed. The need for careful definition of what is a “word,” and the need for tracing through experience how responses come to acquire meaning, hence “wordness,” is emphasized. Levels of wordness are discussed which emerge initially from basic operants and performatives. Evidence is reported in support of the conclusion that it is through direct experience, through the pragmatic application and use of instruments, and through important social relationships that word learning is facilitated. Finally, it is noted that an important step of validation in our own work is in the successful application of methods emanating therefrom to work with mentally retarded children.