Apes and Language

Apes and Language 1

Apes and Language:

A Review of the Literature

Atis Jana

Psychology 1, Section 1

Professor Lawson

April 25

Apes and Language 2

Apes and Language:

A Review of the Literature

Over the past 30 years, researchers have demonstrated that the great apes (chimpanzees,

gorillas, and orangutans) resemble humans in language abilities more than had been thought

possible. Just how far that resemblance extends, however, has been a matter of some

controversy. Researchers agree that the apes have acquired fairly large vocabularies in American

Sign Language and in artificial languages, but they have drawn quite different conclusions

in addressing the following questions:

1. How spontaneously have apes used language?

2. How creatively have apes used language?

3. Can apes create sentences?

4. What are the implications of the ape language studies?

This review of the literature on apes and language focuses on these four questions.

How Spontaneously Have

Apes Used Language?

In an influential article, Terrace, Petitto, Sanders, and Bever (1979) argued that the apes

in language experiments were not using language spontaneously but were merely imitating their

trainers, responding to conscious or unconscious cues. Terrace and his colleagues at Columbia

University had trained a chimpanzee, Nim, in American Sign Language, so their skepticism

about the apes’ abilities received much attention. In fact, funding for ape language research was

sharply reduced following publication of their 1979 article “Can an Ape Create a Sentence?”

In retrospect, the conclusions of Terrace et al. seem to have been premature. Although

some early ape language studies had not been rigorously controlled to eliminate cuing, even as

early as the 1970s R. A. Gardner and B. T. Gardner were conducting double-blind experiments

Apes and Language 3

that prevented any possibility of cuing (Fouts, 1997, p. 99). Since 1979, researchers have

diligently guarded against cuing.

Perhaps the best evidence that apes are not merely responding to cues is that they have

signed to one another spontaneously, without trainers present. Like many of the apes studied,

gorillas Koko and Michael have been observed signing to one another (Patterson & Linden,

1981). At Central Washington University the baby chimpanzee Loulis, placed in the care of the

signing chimpanzee Washoe, mastered nearly fifty signs in American Sign Language without

help from humans. “Interestingly,” wrote researcher Fouts (1997), “Loulis did not pick up any of

the seven signs that we [humans] used around him. He learned only from Washoe and [another

chimp] Ally” (p. 244).

The extent to which chimpanzees spontaneously use language may depend on their

training. Terrace trained Nim using the behaviorist technique of operant conditioning, so it is not

surprising that many of Nim’s signs were