P is for Primate language

24 07 2011

I’ve just seen this somewhat dispiriting documentary about Nim, one of a number of primates who have been sequestered, domesticated, scrutinised, feted, and ultimately abandoned in the name of linguistic research.  Even the shots of the Columbia University forecourt that I walk through every day failed to enliven a story of wanton cruelty, institutional pettiness, dodgy science and bad hair.

The film charts a succession of sudden, traumatic abductions, starting when baby Nim was snatched screaming from his mother’s arms. Over a period of several years, with only humans to interact with, the young chimp was taught to sign, using an adapted form of  American Sign Language, and acquiring a working vocabulary of several hundred words. When he outgrew his cute and cuddly stage, and/or when the funding ran out, he was packed off to a sort of primate Guantánamo Bay. The story is only slightly redeemed by the efforts of one of his former minders to track him down. Even in his hoary old age, Nim still retains a trace of his former competence, pathetically signing ‘play’ from within the bars of his prison.

Columbia University

Frustratingly, the film hardly touches on the linguistic controversies that fuelled this research. In the 1970s, when this unhappy story took place, the debate as to whether only humans are innately equipped with a modular language acquisition device (LAD) was still a fairly hot issue. Not for nothing was Nim named Nim Chimpsky, in (cute) recognition of Noam Chomsky’s role as the leading protagonist of the debate.

What was at stake was this: if highly intelligent apes, exposed to a similar linguistic environment as human children, could acquire an extensive lexicon, but fail to develop even the rudiments of a ‘grammar’, this would go some way towards supporting the view that humans are uniquely hard-wired for language acquisition. On the other hand, if evidence of syntax, however primitive, could be demonstrated, Chomsky’s notion of a ‘Universal Grammar’ (UG) would either need to be extended to nonhuman primates, or it would need to be re-evaluated entirely.

And the findings? Nim’s vocabulary was impressive, but more impressive still was his ability to form two-sign, three-sign, and even longer strings: MORE EAT, HUG NIM, BANANA EAT ME NIM, etc. Moreover, a superficial analysis of the data would suggest that Nim was operating according to some kind of embryonic grammar, producing word order patterns not dissimilar to those of human children’s first utterances. For example, he consistently placed the sign for MORE in front of the sign it modified:  MORE TICKLE, MORE DRINK, etc. But, as Jean Aitchison (1983) notes, “a closer analysis showed that the appearance of order was an illusion. Nim simply had a statistical preference for placing certain words in certain places, while other words showed no such preference” (p.55).

However, as Roger Brown(1973) argued, with regard to similar results for Washoe, an earlier case study of primate signing, “While appropriate order can be used as evidence for the intention to express semantic relations, the lack of such order does not establish the absence of such intentions” (p. 41). This is because the use of appropriate word order, of the verb-object type, for example, as in GIVE BALL, is not strictly necessary, since the context in which the utterances are generated usually resolves any ambiguity. That is to say, the pragmatics of the situation renders syntax redundant. But if that is the case, why do (human) children show evidence of a proto-syntax right from the start?

In the end, we don’t seem to be much the wiser as to whether the higher primates have a rudimentary LAD, despite all the anguish that was inflicted in trying to find one. Nor, for that matter, do we really know whether humans have an LAD either, or whether their faculty for language acquisition isn’t just a spin-off of their vastly more developed cognitive capacities.

What we do know is that the chimpanzees who have been studied do not use their linguistic capacities in the same way as humans, even very young ones, do. Nim, for example, rarely initiated a conversation, and was unable to grasp the basics of turn-taking. As Aitchison (1983, p. 57) concludes, “Nim did not use his signs in the structured, creative, social way that is characteristic of human children”.

In fact, Nim’s ‘language’ was simply a more elaborated version of the way chimpanzees use gestures and vocalizations in the wild: to regulate two-way social interactions such as grooming, feeding, and play. As Tomasello (2003, p. 11) puts it, nonhuman primate communication functions “almost exclusively for imperative motives, to request a behavior of others, not to share attention or information with others in a disinterested manner”.

As someone once said, “Your dog can tell you he is hungry, but not that his father was poor but happy”.

References:

Aitchison, J. (1983). The Articulate Mammal: An Introduction to Psycholinguistics (2nd edn). New York: Universe Books.

Brown, R. (1973). A First Language: The Early Stages. Cambridge, MA.: Harvard University Press.

Tomasello, M. (2003) Constructing a Language: A Usage-based Theory of Language Acquisition. Cambridge, MA.: Harvard University Press.