Sobre la recursión y la sintaxis.

En este post mostraré parte del texto de Fitch, Hauser y Chomsky (2005) en el que se exponen, en la parte de Sintaxis, algunos datos importantes sobre la recursión y la aserción de PJ (Stephen Pinker y Ray Jackendoff ) de que tal vez algunas lenguas no presentan la evidencia de recursión.

Agradezco los importantes comentarios del profesor Miguel Rodríguez Mondoñedo de la Universidad de Indiana y del lingüista Carlos Raúl Molina en el post anterior que permitieron aclarar algunas cuestiones sobre la recursión.

Syntax.

Syntax clearly plays a significant role in our ability to construct and express new meanings, but at least some of the restrictions and complexities of this process are plausibly inherited from conceptual structure, rather than being part of syntax per se. Just as the conceptual structure of objects and events surely influences and constrains the properties of nouns and verbs, it seems plausible to postulate that linguistic devices expressing quantity, tense, aspect or comparison, or other temporal or logical relations, inherit at least some of their structure from the conceptual structure of time, space and logic. The precise locus of such constraints is an active area of current research in linguistics. If there do turn out to be purely syntactic aspects of constituents such as complementizers, auxiliaries, or function words, their existence in other domains (such as music, spatial or social cognition) or in other species, would still require empirical investigation. Such features would not automatically be part of FLN.

Our suggestion that recursion is part of FLN, as defined, is based on the following observations. (1) Recursion is agreed by most modern linguists to be an indispensable core computational ability underlying syntax, and thus language; (2) Despite decades of search, no animal communication system known shows evidence of such recursion, and nor do studies of trained apes, dolphins and parrots; (3) The perceptual data currently available indicate that monkeys cannot even process hierarchical phrase structure, much less recursion; and (4) There are no unambiguous demonstrations of recursion in other human cognitive domains, with the only clear exceptions (mathematical formulas, computer programming) being clearly dependent upon language. Thus, current data justify our placing syntactic recursion in FLN. This assignment would clearly be threatened by a claim of similar recursion in birdsong or the discovery that chimps can process recursive strings, or various other potential empirical findings—all signs of a strong, falsifiable hypothesis. Of course, there’s not a lot riding on this, since we don’t suggest that onlyphenomena in FLN are worthy of study. If future empirical progress demonstrates that
FLN represents an empty set, so be it. A terminological distinction may well outlive its usefulness. For now, though, our hypothesis 3 seems both plausible and consistent with the available data.

We will discuss PJ’s assertion that some of the world’s languages might lack “evidence of recursion” only briefly, because this seems to us irrelevant to the questions under discussion. Modern linguistics asks questions about the biological capacity to acquire human language, a set that includes but is not limited to the huge variety that currently exists on our planet. The putative absence of obvious recursion in one of these languages is no more relevant to the human ability to master recursion than the existence of three-vowel languages calls into doubt the human ability to master a five- or ten-vowel language. A Piraha child raised in a Portuguese, English or Chinese environment will master those languages with the same ease as his or her mother’s tongue, just as the same child could learn the recursive embedding principle of parentheses in mathematics, or a computer programming language with recursive structure. In the face of the huge number of human languages that have clausal embedding, the existence of one that does not would in no way alter the explanatory landscape. If anything, this example would seem to add to the grounds for doubting that recursion evolved “for” communication (whatever this means Discussion / Cognition 97 (2005) 179–210 203 exactly), if a language is attested that gets along without it. But it surely does not affect the argument that recursion is part of the human language faculty: as Jackendoff (2002) correctly notes, our language faculty provides us with a toolkit for building languages, but not all languages use all the tools.

The inability of cotton-top tamarins to master a phrase-structure grammar (Fitch & Hauser, 2004) is of interest in this discussion primarily as a demonstration of an empirical technique for asking linguistically relevant questions of a nonlinguistic animal. It is clearly too early to conclude that all species are equally hobbled (especially given the paucity of species and methods tested). Nor would we be prepared to draw strong conclusions about innate human abilities until infants or young children have been tested, and until more is known about the neural and psychological basis for the human ability to learn phrase structure (all topics of current investigation). Fitch & Hauser do not even mention recursion in the cited paper, and the generation of limited-depth hierarchical phrase structure was not confused with recursion in that paper (although it was by some commentators on the article). The article does suggest that an inability to perceive and process phrase structure, by any animal, would be a severe impediment to that species’ ability to master language. But to the extent that phrase structure is important to music, it would be a correspondingly severe impediment to their mastering a human musical style. If further empirical research shows that no nonhuman species can master a phrase-structure grammar, the hypothesis that animals either lack any recursive mechanisms, or cannot apply them to auditory strings, will be left standing. But if, for example, we discover that songbirds can master phrase-structure grammars, further research will be necessary to determine how they do it, whether this ability involves recursion, whether it is applied across different domains or problems, and whether the mechanism they use is similar or different to that in human beings. The importance of this work is its introduction of an empirical technique capable of addressing these issues, incorporating the formal analysis of language. The empirical technique can be used in a wide range of species, and the hypothesis can be empirically tested and falsified.

En: Hauser, M.D., N. Chomsky y W.T. Fitch. 2005. “The evolution of the language faculty: Clarifications and implications”, en Cognition, 97, págs. 179-210.