Sherman, Austin, and Kanzi

Substantial but still questionable proof about the existence of language in chimpanzees has come from two chimpanzees named Sherman and Austin. In "Communication, Symbolic Communication, and Language: Reply to Seidenberg and Petitto," Sue-Savage Rumbaugh discusses some of this evidence. After a considerable amount of training, Sherman and Austin were able to group lexigrams into different categories such as food and tools despite the absence of the objects themselves. If a chimpanzee can group the lexigram for “banana” under the category “fruit” without an actual banana being present, then we may conclude that some level of understanding is present.

Further indications about symbolism in chimpanzees came from a chimpanzee named Kanzi. If Kanzi really has an understanding of the words he is using then we can assume that if his environment changes than so will his language. Kanzi’s use of the lexigram “Matata” always resulted in being able to visit the colony room to spend time with his mother or other chimpanzees. At first, it is easy to assume that this is probably just the result of an association that Kanzi has made in which the “Matata” lexigram= a visit to the colony room. In other words, for Kanzi, the “Matata” lexigram does not actually represent his mother. However, as soon as Matata was moved to a different area, he stopped using the “Matata” lexigram to go to the colony room and instead began using only the “colony room” lexigram. Could this mean that Kanzi understood that the “Matata” lexigram was a symbolic representation of his mother?

Rumbaugh stresses that such evidence has arisen in the absence of conditioning and an emphasis on comprehension. She makes clear that the “comprehension of spoken words was not mediated by, nor linked to, any desired outcome such as food or travel…responses to such requests provided no special consequences and did not permit Kanzi to obtain desired outcomes that he would not otherwise have received.” However, I don’t think that just because signing “banana” does not result in an actual banana that we can conclude that there is some form of symbolic communication going on. I think it is important to note that reinforcers (any stimulus that increases a behavior) vary between individuals and that they can be just about anything. So, even if Kanzi isn’t receiving bananas for a correct response, the simple smile on a trainer’s face may be enough to increase that response. Kanzi may be making an association in which choosing the “banana” lexigram results in a happy trainer. This is contrary to the idea that the “banana” lexigram forces Kanzi to form a mental representation of an actual banana in his mind. But is this any different than when a child is first learning to speak? Aren't children often rewarded as a result of saying a new word? So why is reinforcement such a big deal in the language training of chimpanzees?